Dissertations / Theses on the topic 'Cave insects'

This study lists and compares insect herbivores of Senecio inaequidens and of Senecio pterophorus around Butterworth by 18 Tables and 38 Figures. The two plant species are widely distributed around Southern Africa. Samples were taken during a month of each of the four main seasons of the year, which in Butterworth did not show much difference in temperature. The two plant species shared generalist insect herbivores most of which were also on other surrounding plant species. The population of most of the herbivores was affected by the seasons while the two plant species were not seasonal, thus the correlation between insect herbivores and the two plant species was not significant. The heavier, and apparently chemically protected species, Senecio pterophorus, accommodated borers and supported a wider variety of but fewer individual insects. Senecio pterophorus could be having more defences but had more serious herbivores. There were no serious insect herbivores that could control the abundance of the two plant species around Butterworth. Anatomical differences between S. pterophorus and S. inaequidens could be highlighted by the kind and number of insect herbivores found upon them. Similarities were more difficult to identify through studying their insect herbivores. The biology of one serious weed, Lixus sp., on Senecio pterophorus was studied in more detail. The life cycle of the weevil was found to be synchronised with that of the host. This weevil shared the stems with other species of weevils with no indication of competition.

Capsicum baccatum var. pendulum was first grown in the Makana District in 2005. Extremely little was known about best practices for cultivation or the insects and diseases associated with the crop in this area. The study was conducted during the second year of production, November 2005 and November 2006, in an attempt to identify the composition and phenology of insects occurring on C. baccatum. In the more rural parts of the Eastern Cape, and more particularly in Grahamstown, there are very few industries. With the advent of this new agricultural venture, a processing factory has been opened in Grahamstown creating more than 600 seasonal jobs in the factory and 1000 seasonal jobs on farms for local people. This business enterprise has not only brought about the creation of jobs, but also training and skills development and empowerment, generating much-needed income in this area. An extensive literature review yielded limited information on insect pests associated with Capsicum. Data from a pilot sampling trial undertaken were statistically analyzed to establish the number of plants to be scouted per site and the most effective scouting techniques to use. Based on the data available and insects collected during the pilot sampling trial, a surveillance programme was designed. Five different types of monitoring traps were placed in each of the eight study sites. Collection of trap catches and scouting of fifteen individual plants per site was undertaken on a weekly basis over the 52-week study period. The most commonly occurring potential insect pests were African Bollworm Helicoverpa armigera (Hübner), False Codling Moth Thaumatotibia leucotreta (= Cryptophlebia leucotreta) (Meyrick), Mediterranean Fruit Fly Ceratitis capitata (Wiedemann) and several species of thrips. Population densities of these pests and their phenology on Capsicum were determined. Statistical analyses established the efficacy of the monitoring traps for each pest, tested for differences among and between study sites, calculated an estimate of the number of pods damaged and a measure of plant damage.The results show that the majority of damage caused to the Capsicum baccatum cropping system was due to Mediterranean Fruit Fly populations. It was established that, although African Bollworm and False Codling Moth were present during the study period, their numbers were negligible and only nominal damage was caused by these pests. Damage caused by thrips species was apparent but not quantifiable. Intervention strategies using an Integrated Pest Management approach, are discussed.

This thesis concentrates on evolutionary costs and benefits of insect parental care. I use phylogenetic methods to test large-scale hypotheses, and field studies to test proximate hypotheses. Initially I look at the evolution of variation in the sex performing care, reconstructing transitions across insect evolutionary history. Consistent with theory, early insects had no care, and their descendants evolved either male care, or female care followed sometimes by biparental care. Secondly, I investigate parental care trade-offs. I find that in insects, care is associated positively with offspring survival but negatively with fecundity, suggesting a general trade-off between current and future reproduction. In the second part of the thesis, I use the assassin bug genus Rhinocoris to investigate proximate costs and benefits influencing male care, the rarest form of care. High density is predicted to favour male care; I investigate why male-caring Rhinocoris live at high density on the plant Stylosanthes. Plant preference is rare in predators and I show that the plant protects eggs from predators as well as harbouring favourable prey, factors not usually linked to parental care. Lastly I investigate an unstudied sexual conflict in male-carers. If females prefer caring males, males should be selected to display their eggs conspicuously. Conspicuousness may carry costs to eggs, so females should prefer inconspicuous locations. In the field this conflict exists for one Rhinocoris species but is absent in a sister species, showing that parental care can have complex effects. My results show that while broad patterns of costs and benefits largely follow theory, finer patterns depend on subtle ecological factors.

Orientadores: Gustavo Henrique Goldman, Juliana Velasco de Castro Oliveira<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia<br>Made available in DSpace on 2018-08-25T09:59:21Z (GMT). No. of bitstreams: 1 Utsunomia_Camila_M.pdf: 2245062 bytes, checksum: 1803b81f54da154433e6d40c34e2b884 (MD5) Previous issue date: 2014<br>Resumo: A produção de etanol a partir de resíduos agrícolas, denominada Etanol de Segunda Geração ou Etanol Lignocelulósico, surge como uma alternativa para aumentar a produção de etanol sem necessariamente expandir as áreas destinadas ao cultivo da matéria-prima. A conversão da biomassa em etanol não é economicamente favorável a não ser que a hemicelulose seja utilizada juntamente com a celulose. Entretanto, a levedura Saccharomyces cerevisiae é incapaz de fermentar pentoses, açúcares liberados pela hidrólise da hemicelulose, principalmente xilose. Uma alternativa para que S. cerevisiae produza etanol utilizando pentoses seria modificá-la geneticamente através do uso de genes provenientes de micro-organismos que naturalmente realizam esta conversão. Com o intuito de encontrar novas leveduras assimiladoras de xilose, prospectamos o trato intestinal de larvas de seis insetos parasitas da cana-de-açúcar e dornas de fermentação alcoólica, identificando 49 isolados, dentre eles as leveduras Rhodotorula mucilaginosa UC11 e Ogataea polymorpha FT212L. Neste trabalho, foi feito o isolamento e a caracterização dos genes xyl1 e xyl2, que codificam respectivamente à xilose redutase (XR) e à xilitol desidrogenase (XDH) dessas duas leveduras, assim como a clonagem e a superexpressão de tais genes na cepa industrial de S. cerevisiae Pedra-2 (PE-2). Rhodotorula mucilaginosa UC11 e O. polymorpha FT212L foram avaliadas quanto a habilidade de crescerem em xilose, a expressão dos genes xyl1 e xyl2 e a medição das atividades das enzimas XR e XDH. E pela primeira vez XR e XDH de ambas as leveduras foram expressas heterologamente em S. cerevisiae PE-2 gerando as cepas PE-2 Rm, PE-2 Op 1 e PE-2 Op 2, que foram testadas quanto a capacidade de utilizar xilose para crescimento. Adicionalmente, neste trabalho também foi construída pela primeira vez uma cepa S. cerevisiae PE-2 contendo os genes de Scheffersomyces stipitis, uma vez que esta é uma das melhores leveduras conhecidas capazes de utilizar xilose. Para isso a cepa PE-2 foi modificada geneticamente com o plasmídio pRH 274, contendo os genes superexpressos de xyl1 e xyl2 de S. stipitis e o gene xks1 de S. cerevisiae, que codifica à xilulose quinase (XK), gerando a cepa denominada PE-2 274. Esta levedura recombinante foi caracterizada através de ensaios de curva de crescimento, medição das atividades de XR e XDH e capacidade de co-fermentar xilose e glicose a etanol em biorreator. A cepa PE-2 274 mostrou ser uma cepa de grande potencial para a produção de etanol a partir de meio contendo xilose e glicose, podendo ser a base para a geração de uma cepa competitiva em ambiente industrial visando à produção do etanol de segunda geração<br>Abstract: The ethanol production from agricultural residues, called Second Generation Ethanol or Lignocellulosic Ethanol, arises as an alternative to increase the ethanol production without necessarily expanding the areas for raw material cultivation. The biomass conversion to ethanol is not economically feasible unless hemicellulose is used in addition to cellulose. However, the yeast Saccharomyces cerevisiae is unable to ferment pentoses, released sugars from hemicellulose hydrolysis, mainly xylose. An alternative to S. cerevisiae produces ethanol from pentose is the genetic engineering with genes from microorganisms which naturally perform this conversion. In order to find new yeasts capable to use xylose, we prospected the gut of sugarcane parasitic insects larvae and alcoholic fermentation tanks, identifying 49 isolates, among them the yeasts Rhodotorula mucilaginosa UC11 e Ogataea polymorpha FT212L. In this work were made the isolation and characterization of xyl1 and xyl2 genes, which encode xylose reductase (XR) and xylitol dehydrogenase (XDH), respectively, from these two yeasts, and the cloning and overexpression of these genes in the industrial S. cerevisiae strain Pedra-2 (PE-2). Rhodotorula mucilaginosa UC11 and O. polymorpha FT212L were evaluated over the ability to grow on xylose, xyl1 and xyl2 expression analysis and XR and XDH activity. And for the first time XR and XDH from both yeasts were heterologous expressed in S. cerevisiae PE-2 generating PE-2 Rm, PE-2 Op 1 and PE-2 Op 2 strains, which were tested by the capability to grow on xylose. Additionally, in this work was constructed also for the first time a S. cerevisiae PE-2 strain with genes from Scheffersomyces stipitis, since this is one of the best known yeasts capable of utilizing xylose. For this, PE-2 was engineered with pRH 274 plasmid, containing xyl1 and xyl2 from S. stipitis and xks1 from S. cerevisiae, which encodes xylulokinase (XK), generating the PE-2 274 strain. This recombinant strain was characterized through xylose growing assays, XR and XDH activity and xylose/glucose co-fermentation to ethanol in bioreactor. PE-2 274 showed a high potential to produce ethanol from xylose and glucose, and could be the basis for the generation of industrially competitive yeast aiming the second generation ethanol production<br>Mestrado<br>Microbiologia<br>Mestra em Genética e Biologia Molecular

Interactions between insects have been shown to be important regulators of population abundances and dynamics as well as drivers of spatial segregation and distribution. These are important aspects of the ecology of insects used in biological control and may have implications for the overall success of a particular programme. In the history of biological control there has been a tendency to release a suite of agents against a weed, which in some cases has increased the level of success, while in others little change has been observed. In most of these cases the implications of increasing the level of complexity of the system is not taken into account and there is little research on the effect of releasing another agent into the system. A brief meta-analysis was done on all the biological control programmes initiated in South Africa. Emphasis was placed on multi-species releases and the effects that overlapping niches were having on the number of agents responsible for the success of a programme. Where overlapping niches were present among agents released the number of agents responsible for success was lower than the number established. Water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach in South Africa has more arthropod agents released against it than anywhere else in the world, yet control has been variable. If the biology and host utilisation of all the agents against water hyacinth is considered, a definite overlap of niches is apparent in at least one life stage of all the agents. Therefore the probability of these insects interacting is high, especially if they are established at the same site in the field. Three of the insects released in South Africa have been selected to investigate possible interactions. They are Neochetina eichhorniae Warner, Neochetina bruchi Hustache and Eccritotarsus catarinensis (Carvalho). Y-tube olfactometer bioassays were used to measure responses of these insects to water hyacinth with prior feeding damage by either conspecifics or heterospecifics. This was done to determine whether olfactory cues played a role in host acceptability and avoidance of conspecifics or heterospecifics. The insects were given a choice between damaged and undamaged plants in various combinations. There was a significant preference for the undamaged plants when given a choice between undamaged and damaged plants. However when the insects were given a choice between two damaged plants there was no discrimination between heterospecific or conspecific damaged plants. This may indicate that there is little or no ecological cost for the insect to share a plant with other insects utilising a similar resource. Insect – insect interactions were investigated in a common garden plot experiment to measure the impact that pairwise combinations of the insect may have on their performance. There was a significant interaction between the mirid E. catarinensis and the weevil N. eichhorniae, with the weevil not performing as well when in combination with the mirid than when alone. Interestingly there was a negative interaction between the two weevil species when in combination, however it was impossible to determine which species was being affected if not both. None of the insects performed significantly better when in combination with another insect. A field study on Wriggleswade Dam in the Eastern Cape, South Africa was initiated to determine whether the relationship between the mirid E. catarinensis and the weevil N. eichhorniae could be determined in the field. The performance of the insects at the different sites in the field suggests that there was an interaction between the agents. This interaction did not limit the establishment of either insect at a site, but it did result in one insect dominating at a site over another. Interactions between the three species of insect tested in this thesis suggest that there are both negative and neutral relationships between them. A basic comparison between the insect performances from 15 sites around the country was done to determine if the spatial segregation observed in the field could be extrapolated to the natural South African situation. The interaction observed between N. eichhorniae and E. catarinensis does seem to extrapolate to the general South African situation where there is definite spatial segregation on a landscape level. The co–occurrence of the two Neochetina weevils at these sites suggests that the negative relationship observed between them in the common garden experiment does not extrapolate to the field. The results from this thesis suggest that the interactions between the agents tested would not limit establishment or have significant ramifications on performance. However, there may be spatial and temporal segregation of these species in the introduced range.

Ao longo do processo evolutivo, parasitóides desenvolveram a habilidade de manipular inúmeros processos fisiológicos de seus hospedeiros. Entre os efeitos induzidos pelo parasitismo, incluem-se alterações no ambiente nutricional, sistema endócrino e imunológico do hospedeiro, além da manipulação da capacidade de síntese protéica de seus tecidos. O tecido adiposo é o principal órgão de síntese de proteínas em insetos e a manipulação de sua atividade é de fundamental importância para o sucesso do parasitismo. Este trabalho teve por objetivo avaliar a expressão gênica do tecido adiposo de Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) parasitada por Cotesia flavipes (Cameron) (Hymenoptera: Braconidae), visando à obtenção de dados para o desenvolvimento de novas estratégias de controle da broca da cana-deaçúcar. Lagartas de D. saccharalis na pré-muda para o último ínstar foram separadas, sendo parte delas sujeita ao parasitismo por C. flavipes, enquanto outra foi mantida como controle. O tecido adiposo de hospedeiros sadios e parasitados foi coletado 1, 3, 5, 7 e 9 dias após o parasitismo e submetido a extração de RNA, síntese de cDNA e análise de expressão gênica diferencial via DD-PCR (Differential Display PCR). Fragmentos expressos diferencialmente entre os tratamentos foram selecionados, clonados e sequenciados. As sequências obtidas foram comparadas àquelas disponíveis em banco de dados. C. flavipes induziu alterações na expressão de um transcrito codificador de uma proteína de armazenamento logo no início do parasitismo. As proteínas de armazenamento, ou hexamerinas, apresentam grande importância no desenvolvimento de insetos, atuando como fonte de aminoácidos a serem utilizados pela pupa e adulto durante a metamorfose e reprodução. Dada a importância desta proteína, o cDNA responsável por sua codificação foi caracterizado via extensão das porções terminais 5 e 3. A sequência completa do cDNA apresentou 2.353 pb, e o polipeptídeo deduzido, 745 aminoácidos. O conteúdo de metionina e aminoácidos aromáticos, bem como a análise filogenética realizada, indicaram que a hexamerina identificada em D. saccharalis é uma proteína rica em metionina. A identificação e caracterização da hexamerina de D.saccharalis podem representar o primeiro passo para o desenvolvimento de novos métodos de controle da broca da cana-de-açúcar, baseados nas interações hospedeiro-parasitóide<br>During evolution, parasitoids evolved the ability to manipulate the physiology of their hosts. Among the common effects of the parasitism, hosts may show an alteration of their hemolymph composition (parasitoid nutritional environment), endocrine and immune systems, and protein synthesis activity of host tissues. The fat body is the main organ of protein synthesis of insects and the manipulation of its activity is key for parasitoid successful development. The goal of this study was to evaluate the effects of parasitization by Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) on the gene expression activity of the fat body of Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), to provide additional information on key regulatory pathways to control host metabolism as a step forward for the development of new control strategies based on parasitoid host regulation strategies. Fifth-instars of D. saccharalis at the head slippage stage were isolated and separated in two different groups. One group was individually parasitized by C. flavipes, and the other was kept as control. The fat bodies of parasitized and non-parasitized hosts were collected 1, 3, 5, 7 and 9 days after parasitism, subjected to RNA extraction, cDNA synthesis and differential gene expression analysis by DD-PCR (Differential Display PCR). Transcripts that were differentially expressed between treatments were selected, cloned and sequenced. The obtained sequences were compared to those available at the NCBi data bank. C. flavipes up-regulated the expression of a transcript enconding for a storage protein soon after parasitization. The storage proteins, or hexamerins, are essential for insect development, acting as a reservoir of aminoacids and nitrogen to be used by the pupa and adults during metamorphosis and reproduction. Due to the importance of these proteins, the cDNA encoding this protein was characterized by the amplification of 5 and 3 terminal ends. The complete cDNA has 2,353 bp and the deduced aminoacid sequence is 745 aa long. The methionine and aromatic aminoacids content, as well as phylogenetic analysis, indicated that the hexamerin identified in D. saccharalis is a methionine-rich protein. The identification and characterization of the hexamerin identified in D. saccharalis is the first step towards to the development of new control strategies based on host-parasitoid interactions.

The Cape Horn Biosphere Reserve, within the remote Sub-Antarctic ecoregion is a reservoir of expressions of biological and cultural diversity. Although it is considered one of 24 wilderness areas remaining in the world, it is not free from local and global threats, such as invasive species, and climate change. Field biologists and philosophers associated to the Sub-Antarctic Biocultural Conservation Program and the Omora Ethnobotanical Park, have worked to describe the region’s biocultural diversity, linking ecological and philosophical research into education, ecotourism, and conservation, through a methodology called field environmental philosophy (FEP), which integrates ecological sciences and environmental ethics through a 4-step cycle consisting of: 1) interdisciplinary research; 2) composition of metaphors; 3) design of field activities with an ecological and ethical orientation; and 4) implementation of in situ conservation areas. In this context, the purposes of this dissertation were to: 1) provide a comprehensive review of publications regarding the conservation status of aquatic and terrestrial insects at a global scale and with an emphasis in southern South America; 2) study the distribution of benthic macroinvertebrates through the sharp altitudinal gradient of the Róbalo River watershed; 3) describe the life histories of Gigantodax sp (Simuliidae: Diptera) and Meridialaris chiloeense (Leptophlebiidae: Ephemeroptera) in the Róbalo River and to assess the potential effects of climate change on their phenology; and 4) to apply FEP methodology in order to better understand and communicate the intrinsic and instrumental values of freshwater invertebrates in the Cape Horn Biosphere Reserve.

As part of a long term ecological monitoring effort at Mammoth Cave National Park, a blind cave beetle, Neaphaenops tellkampfi, was collected and data on populations trends gathered from September 2005 through December 2006 in Great Onyx Cave. The sex and age of each individual in each of 15 sites were determined and density trends of the entire population was measured. The species was chosen due to its role as an indicator species, since potential anthropogenic threats to the environment can be detected via population response. This was the initial implementation of a new monitoring method and a test of its efficacy was conducted by comparing observed trends to those of past studies. Of interest were changes in density, sex ratio, habitat preferences between sexes, and sclerotization class through five seasons. Population trends were congruent with the results of previous studies in this cave. There was a shift from the previously reported constant 1:1 sex ratio to one of female dominance in spring 2006. It was also discovered that males and females of both sclerotization classes utilize habitats among seasons similarly and display greatest trap abundance near large patches of sandy substrate. It was concluded that the ethod is an efficient evaluation tool though recommendations are made for its refinement as it is extended to additional sites. The first survey of the caves of Ghana was conducted in January of 2006. All insects observed were collected and identified in the laboratory to as specific a level as possible. The fauna appears to be more troglophilic rather than troglobytic and is likely that many of the species found inside the caves are likely to occur outside this habitat too.

The inadequacy of arbitrarily classifying interactions between species as antagonistic, neutral or mutualistic has become clear in recent years. Both direct and indirect interactions between species can vary between mutualism and antagonism, depending on the intrinsic and extrinsic contexts of the interaction. This study investigated the characteristics of an ant-plant-homopteran interaction in southern Africa. The polyphagous homopteran Hilda patruelis (Tettigometridae) feeds primarily on the trunk-borne fruiting branches and figs of the Cape fig tree, Ficus sur, and produces honeydew which attracts tending ants. Ten of the sixteen ant species/species groups present on F. sur tended H. patruelis, with Pheidole megacephala the most frequent attendant. Ants attracted to F. sur by H. patruelis honeydew or other liquid food sources also preyed on insects on the tree, including adults of the small agaonid fig wasps whose larvae feed on the ovules in the developing figs. One fig wasp species (Ceratosolen capensis) is also the tree's only pollinator. No benefits to H. patruelis from being tended by ants were detected, either in terms of reduced parasitism, or predation by a lycaenid caterpillar. A P. megacephala colony foraging on a F. sur tree was found to receive a high proportion of its likely energy requirements from the tree, mainly in the form of H. patruelis honeydew, during periods when it was bearing fruit. It is probable that the H. patruelis-P. megacephala interaction constitutes a direct mutualism at times, but that benefits to the homopteran are intermittent or weak. Both H. patruelis and ants benefitted from F. sur, directly or indirectly, through the provision of food (and for some ants, nesting sites). The removal of phloem sap by H. patruelis did not detectably reduce the trees' reproductive output, either in terms of pollinator or viable seed production. The indirect effects of ant and H. patruelis presence on the F. sur trees were on average positive, as ants preyed disproportionately heavily on fig wasp species parasitic on or competing with the pollinator, thus increasing pollinator production. Effects of ant presence on seed production were not investigated, but have been demonstrated as beneficial elsewhere. However, there is great varatlon both in the composition of the wasp fauna arriving to oviposit at different crops, and in ant densities per fig, on several temporal and spatial scales. This results in high variability in the effects of ants on the pollinator and, through it, the tree, from positive to zero and potentially even negative. Despite this conditionality of beneficial outcomes for the tree, the mean effect of ants on the F. sur population studied was to increase pollinator production by up to nearly 20%. This study is among the few to have demonstrated an overall benefit to a plant of having homopteran-tending ants present on it.

Thesis (PhD(Agric) (Conservation Ecology and Entomology))--University of Stellenbosch, 2010.<br>ENGLISH ABSTRACT: See full text document for abstract<br>AFRIKAANSE OPSOMMING: sien volteks dokument vir die opsomming

Dissertation (PhD)--University of Stellenbosch, 2006.<br>ENGLISH ABSTRACT: The central goal in macroecology is to determine species diversity patterns across ecological gradients. Altitudinal and latitudinal patterns in species richness are often assumed to be analogous. Furthermore, the primary mechanisms underlying richness patterns along these two gradients might be similar. To date, few studies have tested whether the hypotheses proposed to explain latitudinal richness variation apply to patterns across altitude. This study therefore tests several hypotheses proposed to explain patterns in species diversity (i.e. ambient energy, productivity, area and geometric constraints) and their underlying mechanisms using altitudinal gradients in epigaeic ant and beetle species richness in the Greater Cederberg Biodiversity Corridor (GCBC) (Western Cape, South Africa). The study was conducted across an altitudinal gradient that was laid out from sea level to the top of a mountain (approximately 2000 m above sea level) and down the other side thereof. First, it was determined how the ant and beetle assemblages differ between the main vegetation types included in the transect and which environmental variables might underlie these differences. Thereafter, the variation in species richness and range size patterns of the two groups was investigated across the full altitudinal gradient. This is the first study that tests the applicability of two mid-domain models across such an altitudinal gradient using both complete and partial assessments. The models explained large proportions of the variance in range sizes across three domains but the ranges could have been constrained to show peaks in the middle of the domains due to the way in which the boundaries of the domains were selected. By contrast, the mid-domain models were not important in explaining species richness patterns, which suggests that they cannot explain diversity across the gradient. The species richness patterns of the two groups did not show the predicted mid-altitudinal peak. Moreover, it was demonstrated that different processes structure ant and tenebrionid assemblages across the same altitudinal transect. Ant species diversity was highly correlated to contemporary climatic variables, while historical factors appear to play a more important role in structuring tenebrionid beetle assemblages. Furthermore, support was found for the species energy theory in the ant assemblages, as well as for two of its underlying mechanisms, namely the more individuals hypothesis and the niche position mechanism. These results suggest that there are likely to be substantial and complex changes to ant assemblages under the predicted climate change scenarios for the region. Given the crucial role played by this group in ecosystem functioning (e.g. myrmecochory) it is suggested that these responses are not likely to be a response solely to vegetation changes, but might also precipitate vegetation changes. This study also forms the basis of a long-term monitoring programme to establish baseline data for the epigaeic ants and tenebrionids and to monitor changes in these communities due to climate change.<br>AFRIKAANSE OPSOMMING: Een van die sentrale idees in makro-ekologie is om die patrone in spesies diversiteit oor ekologiese gradiënte te ondersoek. Verder word daar aangeneem dat spesie rykheidspatrone oor hoogte- en breedtegradiënte analoog is aan mekaar en dat die primêre onderliggende meganismes van die patrone dieselfde kan wees oor hierdie twee gradiënte. Tot dusver het min studies getoets of die voorgestelde hipoteses wat breedtegradiënte in spesie rykheid verduidelik van toepassing is op hoogtegradiënte. Hierdie studie toets dus verskeie van hierdie hipoteses (aanvoelbare temperatuur, produktiwiteit, area en geometriese beperkinge) en hulle onderliggende meganismes in mier en kewer spesie rykheid in die Groter Cederberg Biodiversiteits Korridor (GCBK) (Wes Kaap, Suid Afrika). Die studie is uitgevoer oor ‘n hoogtegradiënt wat vanaf see vlak tot ongeveer 2000 meter bo seevlak en weer aan die ander kant van die berg af uitgelê is. Eerstens is daar bepaal hoe die mier en kewer diversiteit verskil tussen die hoof planttipes wat oor die hoogtegradiënt voorgekom het en watter omgewingsveranderlikes daarvoor verantwoordelik is. Daarna is die variasie in spesie rykheid en area van verspreiding van die twee groepe ondersoek oor die hele hoogtegradiënt. Hierdie is die eerste studie wat die toepaslikheid van twee mid-domein modelle oor so ‘n hoogtegradiënt toets met behulp van volledige en gedeeltelike ondersoeke. Die modelle het baie van die variasie in area van verspreiding verduidelik oor drie domeine maar die areas van verspreiding kon beperk gewees het om pieke in die middel van die domeine te vorm as gevolg van die manier waarop die grense van die domeine gekies is. In teenstelling, het die modelle nie spesie rykheid verduidelik nie en dus kan hulle nie spesie diversiteit oor hierdie gradiënt verduidelik nie. Die spesie rykheidspatrone van die twee groepe het nie die verwagte piek by midhoogte gewys nie. Verder het verskillende prosesse mier en kewer groeperings oor die hoogtegradiënt gestruktureer. Mier diversiteit was hoogs gekorroleer met kontemporêre klimaatsveranderlikes, terwyl historiese faktore belangriker was vir die kewers. Die spesie-energie teorie was ondersteun deur die data, asook die meer individue hipotese en die nis posisie meganisme. Hierdie resultaat dui daarop dat daar moontlik komplekse veranderinge in mier groeperings gaan plaasvind soos die klimaat verander. Miere vervul belangrike ekologiese prosesse in ekosisteme, wat beteken dat die laasgenoemde verandering nie bloot net gaan plaasvind as gevolg van veranderinge in die plantegroei nie, maar dat hulle self ook veranderinge kan veroorsaak. Hierdie studie vorm ook die basis van ‘n langtermyn moniteringsprogram om basislyn data vir hierdie twee ekologies belangrike groepe vas te stel en om veranderinge wat in hierdie gemeenskappe plaasvind, as gevolg van klimaatsverandering, te monitor.

Mathematical models of disease can aid understanding of, and provide a framework for, the study of disease spread and control. Vector-borne diseases are not only amongst the most significant diseases but also require tailored mathematics to model the specific biological interactions important in their spread. A key model in vector-borne epidemiology is the Ross-Macdonald ODE model. Simplification of this model using the quasi-equilibrium assumption (QEA) allowed stability and bifurcation analysis to be performed. The QEA was then used to examine the effect of avian malaria upon the Hawaiian honeycreeper, including ecological factors such as predation and climate change. In contrast, amendments to the Ross-Macdonald model can incorporate higher levels of biological detail, specifically age and bite structure in the vector population. This was facilitated via a PDE model which led to the better understanding of biological mechanisms upon disease transmission and control. Disease-free analytic solutions of the PDE were derived, however the complexity introduced by disease necessitated the use of numerical analysis in order to solve the system. This novel PDE model enabled the study of human African trypanosomiasis. Effects of starvation and teneral susceptibility of tsetse were introduced in a way which is not possible using ODE models. This provides a new framework capable of investigating the impact of these on the control of disease.

Thesis (PhD)--Stellenbosch University, 2011.<br>ENGLISH ABSTRACT: Both taxonomic diversity and diversity of species interaction networks are experiencing declines as a result of agricultural intensification at habitat and landscape scales. Reversing this trend is a key conservation issue, particularly for important functional groups such as flower-visiting insects and the networks within which they interact. This is of great concern in regions of high conservation priority such as the Cape Floristic Region (CFR), known for its high level of floral and faunal endemism and exceptional species turnover. Holistic approach to conservation in agricultural landscapes involves both preservation of natural land and wildlife friendly management of the farm land to achieve conservation targets. The value of these extensive management approaches is yet to be fully assessed, especially in perennial systems such as vineyards. I examined here the effects of vineyard management and landscape context on species richness and abundance of flower-visiting insects and their species interaction networks. Possible taxon specific effects were verified. I also investigated whether vineyards under organic and conventional management homogenized insect-flower interaction networks and whether vineyards with different management practices vary in patterns of species turnover. I sampled flower-visiting insects and their interactions in organic and conventional vineyards, and in natural reference sites. Inclusion of natural reference sites enabled me to make management recommendations for patches of natural vegetation in CFR agricultural landscape. Statistical models showed taxon-specific benefit of organic farm management, and of landscape (distance to natural habitat). There was benefit to monkey beetles (Scarabaeidae) but not to bees (Apidae). Organic vineyards had a higher number of insect-flower interactions than conventional ones, but vineyards under the two types of management were similar in terms of other important network indices. However, networks of the vineyards were more nested than the natural sites, indicating that they may be potentially more stable to perturbation and random extinctions. Multivariate dispersion tests revealed insect-flower interaction networks were not homogenized by both organic and conventional vineyards across the landscapes. I also found, through additive partitioning, that organic and conventional vineyards were similar in terms of species turnover of bees and flowering plants. The findings of this study provide heuristic value to current debates on the value of vineyard habitats for insect conservation. Both organic and conventional vineyards that promote sustainable management of the non-crop floral vegetation between vineyard rows are potential solutions for conservation of flower-visiting insects and their interactions. Also, attention has to be paid to the quality and connectivity of the natural habitat patches that are within CFR agricultural landscape. Site specific management and assessment of the value of these landscape elements is important. Management approaches such as carefully controlled burning may be beneficial, as the CFR natural vegetation is a fire-driven community.<br>AFRIKAANSE OPSOMMING: Taksonomiese diversiteit en diversiteit van spesies-interaksie netwerke ondervind beide afnames as gevolg van landboukundige intensifikasie op habitat en landskap skaal. Om die neiging terug te swaai, is ’n sleutel bewaringsaangeleentheid, veral vir belangrike funksionele groepe soos blom-besoekende insekte en die netwerke waarbinne hulle op mekaar inwerk. Dit is van groot kommer in streke met hoë bewaringsprioriteite soos in die Kaapse Floristiese Streek (KFS), bekend vir sy hoë vlak van plant- en dierendemisme en buitengewone spesies kentering. ’n Holistiese benadering tot bewaring van landboukundige landskappe behels beide die bewaring van natuurlike land en natuurlewe-vriendelike bestuur van die plaasgrond om bewaringsdoelwitte te bereik. Die waarde van hierdie ekstensiewe bestuursbenaderings moet nog volledig bepaal word, veral in meerjarige sisteme soos wingerde. Ek het die uitwerkings van wingerdbestuur en landskapsamehang op spesiesrykheid en volopheid van blombesoekende insekte en hulle spesies interaksie netwerke ondersoek. Moontlike takson-spesifieke uitwerkings is nagegaan. Ek het ook ondersoek ingestel of wingerde onder organiese en gebruiklike bestuur ooreenstemmende insek-blom interaksie netwerke met wingerde met verskillende bestuurspraktyke in patroon van spesies kentering gewissel het. Ek het blom-besoekende insekte en hulle interaksies in organiese en konvensionele wingerde, asook in natuurlike verwysingsgebiede gemonster. Insluiting van natuurlike verwysingsgebiede het my in staat gestel om bestuursvoorstelle vir gebiede van natuurlike plantegroei in KFS landboulandskappe voor te stel. Statistiese modelle toon takson-spesifieke voordeel van organiese plaasbestuur en van die landskap (afstand van natuurlike habitat) self. Daar was voordeel vir bobbejaankewers (Scarabaeidae), maar nie vir bye (Apidae) nie. Organiese wingerde het ’n groter getal insek-blom interaksies as konvensionele wingerde gehad, maar wingerde onder beide tipes van bestuur was soortgelyk in terme van ander belangrike netwerk aanduiders. Netwerke van wingerde was egter meer geklomp dan natuurlike gebiede wat aandui dat hulle potensieel meer stabiel betreffende versteuring en lukrake uitsterwings is. Multivariate verspreidingstoetse het aangetoon dat insek-blom interaksie netwerke by beide organiese en konvensionele wingerde oor landskappe nie eenvormig was nie. Ek het ook bevind deur aanvullende verdeling dat organiese en konvensionele wingerde gelykwaardig was in terme van spesies kentering van bye en blomplante. Die bevindings van hierdie studie verskaf heuristise waarde tot huidige debatte oor die waarde van wingerdhabitatte vir insekbewaring. Beide organies en konvensionele wingerde wat volhoubare bestuur van die nie-gewas plantegroei binne wingerdrye bevorder, is moontlike oplossings vir die bewaring van blom-besoekende insekte en hulle wisselwerkings. Bykomend moet aandag gegee word aan die kwaliteit en verbindings van en tussen natuurlike habitat gebiede binne die KFS landboulandskap. Plekspesifieke (plaaslike) bestuur en bepaling van die waarde van hierdie landskapelemente is belangrik. Bestuursbenaderings, soos noukeurig beheerde brand, mag voordelig wees aangesien die KFS natuurlike plantegroei ’n vuurgedrewe gemeenskap is.

Baculoviruses have been used as biocontrol agents to control insect pests in agriculture since the 1970s. Out of the fifteen virus families known to infect insects, baculoviruses offer the greatest potential as insect biopesticides, due to their high host specificity which makes them extremely safe to humans, other vertebrates, plants and non-target microorganisms. They comprise of two genera: nucleopolyhedroviruses (NPVs) and granuloviruses (GVs). The South African isolate of Cryptophlebia leucotreta granulovirus (CrleGV-SA) which is infectious for the false codling moth (FCM), Thaumatotibia leucotreta, (Meyrick) (Lepidoptera: Tortricidae), has been successfully developed into two commercial biopesticides; Cryptogran® and Cryptex®, for the control of FCM in citrus crops. The current method of enumeration used for CrleGV-SA virus particles in routine experiments during the production of the GV as biopesticides, is dark field microscopy. However, due to the small size of GVs (300-500 nm in length), the technique is not easy to perform on these viruses, and no systemic comparison has been made of potential alternative methods. Therefore, the main objective of this study was to develop a quantitative enumeration method for CrleGV-SA occlusion bodies (OBs) which is accurate, reliable, and feasible, and compare the developed methods of enumeration to the current method. Purified and semi-purified CrleGV-SA viral stocks were prepared for enumeration studies using spectrophotometry, dark field microscopy, scanning electron microscopy (SEM) and real time qPCR. Spectrophotometry was found to be an unreliable method for enumeration of GVs in the production, standardisation, and quality control of biopesticides. Dark field microscopy and SEM were found to be accurate, and statistically comparable (p = 0.064) enumeration techniques. qPCR is currently being optimised for the enumeration of GVs. This technique was demonstrated to generate accurate standard curves for absolute quantification of virus particles for pure and semi-pure virus preparations. qPCR offers the greatest potential as an accurate enumeration method because it is not affected by contamination with non-biological contaminating debris, nor by other biological material due to the specificity of PCR primers. Further work is required to fully develop qPCR as an enumeration method for GVs. However, dark field microscopy has been successfully validated as an enumeration method. SEM, which has a high resolution compared to light microscopy, has an added advantage over dark field microscopy, which is to distinguish virus particles in semi-pure viral stock preparations during counting. Therefore, SEM currently provides the most unambiguous and feasible enumeration method for GVs in both purified and semi-purified virus samples.

Cette thèse vise à explorer l'utilisation de deux technologies émergentes, la Détente Instantanée Contrôlée (DIC) et les Champs Électriques Pulsés (CEP), comme prétraitements pour la transformation des vers de farine dans un concept de bioraffinerie. Les impacts de ces technologies sur la décontamination microbienne des larves, la mortalité (mise à mort), le brunissement enzymatique, le pressage mécanique pour la délipidation et la déshydratation, et le séchage des larves ont été étudiés. Le procédé conventionnel de blanchiment à l'eau chaude a été utilisé comme référence pour la comparaison. Les résultats ont montré que la DIC et les CEP sont deux techniques efficaces pour la mise à mort des larves. L’application de la DIC à 0,3 MPa a entraîné une réduction de la flore aérobie totale et du nombre des levures et moisissures en dessous des seuils fixés par les directives Européennes avec des temps de réduction décimale de 3,8 s et 3 s, respectivement. Le blanchiment conventionnel à 90°C pendant 360 s a également réduit efficacement le nombre de contaminants, mais avec des temps de réduction décimale plus lents de 67,8 s et 57 s, respectivement. En revanche, CEP n'a pas permis de réduire la charge microbienne initiale des larves. Par ailleurs, la DIC a entraîné une amélioration de la clarté du jus de larves, tandis que la couleur du jus des larves blanchies, traitées par CEP et non traitées était beaucoup plus foncée. Ce résultat pourrait être attribué à l'inactivation des enzymes oxydatives par DIC. Le blanchiment suivi d'un pressage a permis d'obtenir un rendement en jus de 68%, une récupération de 48% des protéines et un tourteau contenant 14,7% de lipides/MS et 45% de matière sèche. La DIC et les CEP semblent toutes les deux améliorer ce résultat, mais d’une manière différente. Pour la DIC, l'augmentation de la pression appliquée de 0,15 à 0,45 MPa a réduit le rendement de pressage de 68 à 55 %. Cette baisse de rendement pourrait être attribuée à l'agrégation et la dénaturation des protéines comme il a été montré par spectroscopie de fluorescence. En conséquence, il en résulte une meilleure rétention des protéines dans le gâteau (78% des protéines) et l’obtention d’un gâteau avec 55% de MS dont 12% de lipides/MS. En revanche, le traitement par les CEP a augmenté le rendement de pressage des larves jusqu'à 78 %, entraînant une perte de protéines plus élevée dans le jus (une récupération de 43 % des protéines), et génère un gâteau avec 54% de MS dont 14% de lipides/MS. Les analyses ont montré que le CEP est le traitement qui préserve le mieux la qualité des protéines, suivi du blanchiment puis de la DIC. En outre, la DIC a amélioré la diffusivité de l'eau et a limité le rétrécissement de la taille des larves durant le séchage. De plus, elle a entraîné une augmentation de 125% de la surface spécifique de la farine d’insectes obtenue avec une distribution de taille de particules plus uniforme, ce qui améliore la qualité du produit final. Le traitement par CEP a aussi amélioré le séchage par rapport au blanchiment, mais reste moins efficace que la DIC. Enfin, le traitement par CEP est le moins énergivore (21.7 kWh/t), suivi par le blanchiment (61.7 kWh/t) et la DIC (111 kWh/t)<br>This thesis aims to explore the use of two emerging technologies, the Instant Controlled Pressure Drop (DIC) and the Pulsed Electric Fields (PEF), as pretreatments for yellow mealworms transformation in a biorefinery concept. The impacts of these technologies on larval microbial decontamination, mortality (killing), enzymatic browning, mechanical pressing for defatting and dewatering, and drying processes were investigated. Conventional blanching in hot water was used as a control for comparison. Results showed that DIC and PEF were both efficient killing methods. The application of DIC treatment at 0.3 MPa resulted in the reduction of the total viable count (TVC) and yeasts and molds counts (YMC) to levels below the established European standards with decimal reduction times of 3.8 s and 3 s for TVC and YMC, respectively. Conventional blanching at 90°C for 360 s also reduced the counts, but with slower decimal reduction times of 67.8 s and 57 s, respectively. However, PEF treatment was not successful in reducing the initial microbial load of the larvae. Moreover, the DIC treatment resulted in a marked improvement in the brightness of the larval juice color which may be attributed to the inactivation of oxidative enzymes, whereas the juice color of blanched, PEF-treated, and untreated larvae was much darker. Blanching followed by hydraulic pressing resulted in a 68% pressing yield, a 48% recovery of the initial protein content, and a press cake with 14.7% lipids/db and 45% dry matter. DIC and PEF both seem to improve this outcome, but each in a different way. Increasing DIC treatment pressure from 0.15 to 0.45 MPa reduced the pressing yield from 68 to 55%, which is believed to be caused by protein aggregation and denaturation, confirmed by fluorescence spectroscopy analysis. As a result of the reduced pressing yield, more proteins were retained in the press cake, resulting in a high protein recovery of 78% and a press cake with 55% dry matter and 12% lipids/db. On the other hand, PEF treatment increased the pressing yield of larvae up to 78% resulting in a higher protein loss in the pressing juice, with a protein recovery of 43%. The press cake generated had 54% dry matter and with 14% lipids/db. PEF was found to be the best method that preserves protein quality, followed by blanching then DIC. Moreover, compared to blanched larvae, DIC treatment reduced drying shrinkage and improved water diffusivity. Additionally, the treatment increased the specific surface area of the dried meal by up to 125% and resulted in a more uniform particle size distribution, both of which improve the end product's quality. PEF treatment also accelerated drying compared to blanching but still lags behind DIC in terms of drying kinetics and water diffusivity. PEF was found to be the most energy-efficient treatment (21.7 kWh/t), followed by blanching (61.7 kWh/t) and DIC (111 kWh/t)

This thesis has two focuses. The first problem facing the olive industry in the Eastern Cape is the growers’ perceptions of both what the industry will provide them and what a pest management program might entail. The second focus is the biology of olive pests in the Eastern Cape in terms of understanding their populations and their natural enemies on private farms, with future hopes of understanding how Integrated Pest Management strategies can be developed for this crop. Eastern Cape private farmers, small-scale farmers and workers from agricultural training institutions were interviewed regarding the history and cultivation of the local olive crop. Only one commercially viable olive grove was identified; other groves were small, experimental pilot ventures. The introduction of olives to small-scale farmers and agricultural training schools was generally a top-down initiative that led to a lack of sense of ownership and the trees being neglected. Other problems included poor human capital; poor financial capital; lack of adequate support; lack of knowledge transfer and stability; lack of communication and evaluation procedures of the project; miscommunication; and finally, olive pests. Apart from hesitancy to plant at a commercial scale, the main problem facing private farmers (Varnam Farm, Hewlands Farm and Springvale Farm) was pests. Therefore an investigation of pests from private farms was conducted ranging from collection of cultivated and wild olive fruit and flea beetle larvae for parasitism, trapping systems both for fruit flies and olive flea beetle adults. A survey of olive fruits yielded larval fruit flies of the families Tephritidae (Bactrocera oleae (Rossi), B. biguttula (Bezzi) and Ceratitis capitata (Wiedemann)) and Drosophilidae (Drosophila melanogaster (Meigen)) from wild olives (O. europaea cuspidata (Wall. ex G. Don) Cif.) but none from cultivated olives (O. e. europaea L.). Braconid wasps (Opiinae and Braconinae) were reared only from fruits containing B. oleae and B. biguttula. This suggests that B. oleae is not of economic significance in the Eastern Cape, perhaps because it is controlled to a significant level by natural enemies, but B. biguttula may be a potential economic pest. A survey of adult fruit flies using ChamP traps baited with ammonium bicarbonate and spiroketal capsules and Sensus trap baited with methyl eugenol and Questlure confirmed the relative importance of B. biguttula over B. oleae. ChamP traps were over 50 times better than Sensus traps for mass trapping of B. biguttula but both were ineffective for trapping B. oleae and C. capitata. Six indigenous flea beetles of the genus Argopistes Motschulsky (Chrysomelidae: Alticinae) were found, three described by Bryant in 1922 and 1944 and three new species. Their morphology was investigated by scanning electron microscopy and mutivariate morphometric analysis. The leaf-mining larvae are pests of wild and cultivated olives in South Africa and threaten the local olive industry. At Springvale Farm, A. oleae Bryant and A. sexvittatus Bryant preferred the upper parts of trees, near new leaves. Pseudophanomeris inopinatus (Blkb.) (Braconidae) was reared from 23 Argopistes larvae. The beetle larvae might not be controlled to a significant level by natural enemies because the rate of parasitism was low. The olive flea beetles showed no attraction to traps containing various volatile compounds as baits. The lace bug, Plerochila australis Distant (Tingidae), was sometimes a pest. It showed a preference for the underside of leaves on the lower parts of the trees. A moth, Palpita unionalis Hübner (Crambidae), was reared in very low numbers and without parasitoids. A twig-boring beetle larva, chalcidoid parasitoids and seed wasps of the families Eurytomidae, Ormyridae and Eupelmidae were also recorded.

De nombreuses études ont jusqu'ici considéré les infections comme étant des interactions deux-à-deux, entre un hôte et un pathogène, minimisant ainsi la complexité du processus infectieux. En effet, les infections sont souvent très hétérogènes, menant à des interactions plus complexes. Au cours de ce travail, nous cherchons à répondre à deux questions: (i) La transmission d'un pathogène peut-elle être impactée lorsque de l'hétérogénéité phénotypique apparaît dans sa population au cours de l'infection ? (ii) Comment les pathogènes interagissent-ils avec la communauté bactérienne généralement associée à l'hôte avant l'infection ? Pour étudier ces questions, nous nous sommes intéressés à Xenorhabdus nematophila, une bactérie pathogène d'insectes transmise par un vecteur, le némaotde Steinernema carpocapsae. Au cours d'une infection par X. nematophila, différentes sous-populations ayant différentes caractéristiques phénotypiques sont produites. Nous avons cherché à déterminer les mécanismes moléculaires responsables de cette diversification phénotypique, ainsi que sa potentielle valeur adaptative pour X. nematophila. Nous avons montré que certaines de ces formes phénotypique sont des mutants qui semblent être sous forte sélection positive au cours de l'infection. À l'inverse, ces mutants ont un impact négatif sur la reproduction du vecteur nématode, ce qui réduit leur transmission. La dynamique d'hétérogénéité phénotypique chez X. nematophila semble donc déterminée par des pressions de sélections contraires à court terme et à long terme. La production de molécules anti-microbiennes chez X. nematophila devraient lui permettre de dominer la communauté bactérienne à l'intérieur de l'insecte et faciliter sa ré-association avec son vecteur. Nous avons donc décrit la composition de la communauté microbienne présente dans des insectes morts d'une infection par X. nematophila, et montré qu'en dépit de sa production d'antibiotiques, X. nematophila est loin de dominer la communauté microbienne après la mort de l'insecte. Elle cohabite avec des bactéries provenant à la fois du microbiote de l'hôte insecte, et de celui du vecteur nématode. Cela soulève de nombreuses questions sur le rôle d'autres microorganismes dans les interactions Xenorhabdus-Steinernema, et sur leur influence dans l'évolution de cette symbiose mututaliste<br>Numerous studies have considered infections as pairwise interactions between a single pathogen and its host, sometimes leading to an incomplete picture of infectious processes. In this work, we focused on more complex types of interactions that arise because infections are usually heterogeneous. More precisely, we have investigated two main issues: (I) how pathogen transmission is impacted by phenotypic heterogeneity which arises within the pathogen population during the infection, and (ii) how do pathogens interact with the bacterial community which is naturally associated to the host before infection? To assess these questions, we have been studying Xenorhabdus nematophila, an insect-killing bacterial pathogen which is transmitted by a nematode vector, Steinernema carpocapsae. One interesting feature of X. nematophila is that it produces different sub-populations during the course of an infection, each one having distinctive phenotypic features (e.g. one form produces antibiotics and is mobile, while the other does not produce antibiotics nor flagella). In this work, we first tried to identify the molecular mechanisms responsible for this diversification of phenotypes, and tested if phenotypic heterogeneity in X. nematophila has some adaptive value. We showed that some of these phenotypic forms were mutants, which seem to be under strong positive selection during infection. We also showed, however, that these mutants impair nematodes reproduction, which in turn reduces transmission. Therefore, the dynamics of phenotypic heterogeneity in X. nematophila seems to be determined by contradictory short-term and long-term selective pressures. A second interesting feature of X. nematophila is that it produces a lot of antimicrobial compounds which should allow it to dominate the bacterial community inside the insect it has killed. This can be key to ensure the re-association of X. nematophila with its nematode vector inside the insect cadaver. We investigated the bacterial composition of the microbial communities present in insects cadavers after infection by X. nematophila. We found that despite the numerous antibiotics it is able to secrete, X. nematophila is far from dominating microbial community after host death. It rather cohabits with microorganisms from the microbiota of both the insect host and the nematode vector. This raises numerous questions about the impact of these other microorganisms on Xenorhabdus-Steinernema interactions, and therefore on their potential influence on how this mutualistic association has evolved

Maize (Zea mays L.) is one of the most important crops in South Africa that is cultivated for food, feed and as a cash crop. Maize in the Eastern Cape is typically grown for consumption and the Province is one of the least producers owing to small landholdings, poor production conditions and pests. This study investigated: (i) the different maize cropping systems smallholder farmers practice in the Eastern Cape (EC), (ii) the major maize insect pests within the identified cropping systems, (iii) the perceptions of Eastern Cape smallholder maize farmers on the effects of insect pests, and (iv) the effects of crop residues on insect pests’ population dynamics. Four major cropping systems namely: maize sole cropping without rotations by government sponsored farmers (GCP) (94 percent), maize intercropping without rotations by independent farmers (IF) (79 percent), maize sole cropping without rotations by IF (67 percent) and maize intercropping without rotations by GCP (61 percent) were identified. The choice of a cropping system by the smallholder farmers was significantly influenced by source of sponsorship, the difference in their district localities, tenure system, availability of inputs and farming equipment, percentage of farmland farmers allocate to maize, maize varieties, farming experience, fallow operations and access to irrigation facilities. The major constraints faced by the farmers in maize production are the attack by insect pests, weeds competition, drought, the lack of fencing around the fields and destruction by mammals. The major insect pests identified were stalk borers (Busseola fusca, Chilo partellus), cutworms (Agrotis spp.), aphids (Rhopalosiphum maidis), bollworms (Helicoverpa armigera) and weevils (Sitophylus spp.). The most popular control measures employed were the use of GM maize and pesticides. Results from the field trial showed that field crickets were the major ground dwelling insect pests observed followed by bollworms and cutworms. However, there were no significant influence of residue retention on the insects’ diversity indices, richness, and evenness. Above ground insects sampling revealed the domination by four major insects namely, cutworms, maize stalk borer, bollworms, and spotted stalk borer. Residue management significantly influenced the infestation by spotted stalk borer only on maize plots. However, the general trend was that there was less infestation by the insects in plots where residues were retained than the ones with residue removed. Results from the study indicate that government sponsorship is significantly influencing the maize cropping systems of the smallholder farmers of the Eastern Cape.

Natural proteins can evolve new three-dimensional structures through mutations in their amino acid sequence. For protein families that exhibit such structural diversity, a major challenge is to understand the scope and nature of structure variation and its relationship to sequence evolution. The Cordes laboratory has begun using transitive homology-based methods to identify, target and structurally characterize natural sequences intermediate between pairs of proteins with distant sequence similarity and different structures. As a proof of principle, this dissertation describes structural studies of two proteins in different families as separate case studies, one involving secondary structure evolution and the other involving topological rearrangement. In the first case, crystallography was applied to solve the structure of a sequence intermediate identified through transitive homology analysis of the Cro transcription regulator family. Comparison with another member resulted in finding two proteins with significant sequence similarity yet different secondary structure compositions and folds. In the second case, transitive homology analysis was applied to look at two members of the insect salivary lipocalins, one with the canonical sequential all-antiparallel β-barrel topology, and another with a unique strand-swapped topology. Three sequence intermediate members were found that each have direct sequence similarity to both topologically distinct relatives. Targeting these sequence intermediate members for structural characterization by NMR led to assignment of the canonical lipocalin topology for one intermediate. The results from these two cases indicate that structurally diverse families may contain members with similar sequences but different folds. As such, transitive homology mapping offers a method to identify and target those members for structural characterization.

Les plagues d’insectes són elements integrats a la dinàmica del paisatge forestal. Tot i això, durant les últimes dècades, han experimentat un augment en nombre i impacte, implicant conseqüències severes pels ecosistemes i la societat. Els motius d’aquesta dinàmica són principalment els canvis en l’ús del sòl, els canvis en el clima i la introducció d’espècies invasores degut al comerç internacional i a la mobilitat humana. L’objectiu central d’aquesta tesi és avançar en el coneixement de l’impacte de les plagues d’insectes al paisatge forestal i integrar-lo en eines de modelització que ajuden a la predicció de conseqüències en un futur canviant. Hem basat l’aproximació en definir els efectes directes i indirectes de les plagues d’insectes mitjançant la descripció de les interaccions amb altres pertorbacions del paisatge forestal (el foc, la sequera, les tempestes, la contaminació, etc.) i descriure els mecanismes que hi influeixen. Hem exemplificat el paper de les plagues forestals amb el cas d’estudi de la papallona del boix (Cydalima perspectalis), un lepidòpter originari d’Àsia i invasor a Europa des de 2007. Hem descrit el nínxol ecològic de l’espècie així com la seva distribució i impacte potencial a l’àrea d’invasió. Finalment hem anticipat els impactes d’aquesta plaga i les seves interaccions amb altres pertorbacions a la vessant sud dels Pirineus en un futur regit pel canvi climàtic. Aquesta tesi proposa diferents metodologies per a l’estudi de les plagues forestals i el seu impacte al paisatge. Primer es demostra que per una correcta aplicació dels Species Distribution Models (SDM) en espècies invasores és necessària la combinació d’informació de la zona nativa i la zona d’invasió. Segon, s’ha evidenciat que els models de simulació espacialment explícits són eines adequades per descriure les pertorbacions forestals, identificar els paràmetres clau de la seva dinàmica, analitzar les seves interaccions i anticipar els seus impactes davant la incertesa del canvi global. Finalment, es constata que per tal de fer una aplicació eficaç de les metodologies descrites és necessari diferenciar l’ocurrència d’una pertorbació de la severitat del seu impacte. Els resultats aquí exposats proporcionen noves evidències dels processos que regeixen la dinàmica de plagues forestals i, en concret, de C. perspectalis. Es demostra que la distribució de C. perspectalis al sud dels Pirineus depèn de la presencia de la planta hoste (Buxus sempervirens) i la capacitat d’expansió de l’insecte (que es veu normalment alterada per introduccions antropocòries involuntàries), mentre que no és limitada per la composició de l’habitat. Tot i això, la defoliació severa només es troba en llocs d’alta adequació climàtica, definida per un rang de temperatures diürnes petit i una baixa estacionalitat de la precipitació i la temperatura. Aquestes condicions defineixen un cert patró de continentalitat on els boixos més susceptibles de ser atacats són aquells que es troben a prop de la costa i a baixa elevació (a les províncies de Girona, Barcelona i Navarra) i excloent zones del Pirineu central (Lleida, Huesca). Les projeccions futures de l’impacte causat per C. perspectalis descriuen una relació de consumidor-recurs cíclica amb l’estat dels boixos. A més el canvi climàtic podria reduir l’àrea d’impacte sever causat per l’insecte concentrant-lo només a algunes localitats. La interacció entre C. perspectalis i altres pertorbacions com el foc i la sequera extrema no ha resultat significativa. Tot i això, tal com he descrit en altres espècies d’insectes forestals, les interaccions amb altres pertorbacions són complexes i es produeixen en diverses direccions, efectes (antagònic i sinèrgic) i escales espacials i temporals. Tota aquesta informació ofereix una base de gran valor per a la futura recerca i pel disseny d’estratègies de gestió de boscos i plagues.<br>Las plagas de insectos son elementos integrados en la dinámica del paisaje forestal. Sin embargo, durante las últimas décadas, han experimentado un aumento en número e impacto, implicando consecuencias severas para los ecosistemas y la sociedad. Los motivos de esta dinámica son principalmente los cambios en el uso del suelo, los cambios en el clima y la introducción de especies invasoras debido al comercio internacional y la movilidad humana. El objetivo de esta tesis es avanzar en el conocimiento del impacto de las plagas de insectos en el paisaje forestal y integrarlo en herramientas de modelización que ayudan a la predicción de consecuencias en un futuro cambiante. Hemos basado la aproximación al definir los efectos directos e indirectos de las plagas de insectos mediante la descripción de las interacciones con otras perturbaciones del paisaje forestal y describir los mecanismos que influyen. Hemos ejemplificado el papel de las plagas forestales con el caso de estudio de la mariposa del boj (Cydalima perspectalis), un lepidóptero originario de Asia e invasor en Europa desde 2007. Hemos descrito el nicho ecológico de la especie así como la su distribución e impacto potencial en el área de invasión. Finalmente hemos anticipado los impactos de esta plaga y sus interacciones con otras perturbaciones en la vertiente sur de los Pirineos en un futuro regido por el cambio climático. Esta tesis propone diferentes metodologías para el estudio de las plagas forestales y su impacto en el paisaje. Primero se demuestra que para una correcta aplicación de los Species Distribution Modelos (SDM) en especies invasoras es necesaria la combinación de información de la zona nativa y la zona de invasión. Segundo, se ha evidenciado que los modelos de simulación espacialmente explícitos son herramientas adecuadas para describir las perturbaciones forestales, identificar los parámetros clave de su dinámica, analizar sus interacciones y anticipar sus impactos ante la incertidumbre del cambio global. Finalmente, se constata que para hacer una aplicación eficaz de las metodologías descritas es necesario diferenciar la ocurrencia de una perturbación de la severidad de su impacto. Los resultados aquí expuestos proporcionan nuevas evidencias de los procesos que rigen la dinámica de plagas forestales y, en concreto, de C. perspectalis. Se demuestra que la distribución de C. perspectalis al sur de los Pirineos depende de la presencia de la planta huésped (Buxus sempervirens) y la capacidad de expansión del insecto, mientras que no es limitada por la composición del habitat. Sin embargo, la defoliación severa sólo se encuentra en lugares de alta adecuación climática, definida por un rango de temperaturas diurnas pequeño y una baja estacionalidad de la precipitación y la temperatura. Estas condiciones definen un cierto patrón de continentalidad donde los bojes más susceptibles de ser atacados son aquellos que se encuentran cerca de la costa ya baja elevación (en las provincias de Girona, Barcelona y Navarra) y excluyendo zonas del Pirineo central (Lleida, Huesca ). Las proyecciones futuras del impacto causado por C. perspectalis describen una relación de consumidor-recurso cíclica con el estado de los bojes. Además el cambio climático podría reducir el área de impacto severo causado por el insecto concentrándolo sólo a algunas localidades. La interacción entre C. perspectalis y otras perturbaciones como el fuego y la sequía extrema no ha resultado significativa. Sin embargo, tal como he descrito en otras especies de insectos forestales, las interacciones con otras perturbaciones son complejas y se producen en varias direcciones, efectos (antagónico y sinérgico) y escalas espaciales y temporales. Toda esta información ofrece una base de gran valor para la futura investigación y el diseño de estrategias de gestión de bosques y plagas.<br>Insect pests are integrated elements of forest landscape dynamics. However, an increase in the number of pest outbreaks and in their impact has been experienced in recent decades, causing severe consequences for ecosystems and society. The reasons behind these changing dynamics are mainly related to changes in land-use, climate, and the introduction of invasive species due to international trades and human mobility. The central goals of this thesis are to advance in the understanding of insect pest impacts on forest landscapes and to integrate them in modelling tools that help the prediction of consequences in a global change future. To face these goals, I defined the direct and indirect effects of insect pests and their interactions with other forest landscape disturbances (fire, drought, storms, pollution, etc.), and described the mechanisms underlying these responses. Aiming at working on a specific actual concerning pest, I examined the case of boxwood moth (Cydalima perspectalis), a Lepidoptera native to Asia and invasive in Europe since 2007. I described the ecologic niche of the species as well as its distribution and potential impact on the invaded area. Finally, I anticipated impacts of this pest and its interactions with other disturbances in the Southern Pyrenees under future climatic conditions. In this thesis, I proposed different methodologies to study the impact of forest pests. First, I demonstrated that a combination of information from the native and invaded areas is required for a correct application of Species Distribution Models (SDMs) in invasive species. Second, I evidenced that spatially explicit simulation models are appropriate tools for the study of forest disturbances, identifying key parameters in determining their dynamics, analyzing their interactions, and anticipating their impacts in the face of global change uncertainty. Finally, I highlighted the adequacy of differentiating the presence versus the severity of a disturbance in order to effectively apply the methodologies described. The results presented in this thesis provide new evidence of the processes governing pest dynamics – and their associated impacts – on forest functioning, in particular, the case of C. perspectalis. I demonstrated that the distribution of C. perspectalis in the Southern Pyrenees depended on the presence of the host plant (Buxus sempervirens) and the insect spread capacity (which is usually altered by involuntary anthropochory), while it was not limited by the fragmentation or heterogeneity of the habitat. However, severe defoliation was only found in places with high climatic suitability, defined by low seasonal precipitation and temperature, and low temperature diurnal range. These conditions define a continentality pattern where the most endangered boxwoods were those located near the coast and at low elevation (in the provinces of Girona, Barcelona, and Navarra) and excluding areas of the central Pyrenees (Lleida, Huesca). Future projections of C. perspectalis impact describe a cyclic consumer-resource relationship with the host plant. In addition, climate change may reduce the area of severe impact being concentrated only in few locations. The interaction between C. perspectalis and extreme drought was not significant. However, as I reported for other forest pest species, interactions with other disturbances are complex and occur in various directions, effects (antagonistic and synergistic) and spatial and temporal scales. For instance, trees that are damaged by fire or drought can synthesize ethanol, monoterpenes, and pheromones that attract insects; trees killed by an insect pest result in an accumulation of fuel that facilitates the spread of fires; trees weakened by drought have a lower response capacity (resin synthesis, regrowth capacity, etc.) and are therefore more susceptible to insect attacks. All this information offers a valuable basis for future research and for designing forest and pest management actions.<br>Universitat Autònoma de Barcelona. Programa de Doctorat en Ecologia Terrestre

Thesis (MSc)--Stellenbosch University, 2014.<br>ENGLISH ABSTRACT: Research into the patterns and drivers of insect diversity in the Cape Floristic Region (CFR) lags far behind that of plants. Here I sample insect herbivore communities on a dominant plant family (Restionaceae), and use a spatially nested sampling design and network analysis to evaluate the association between plant and insect diversity in the CFR. I find that plant species richness predicts insect richness better than environmental factors. Turnover in insect communities is strongly associated with turnover in plant (both species and phylogenetic) communities at both local and regional sampling scales, suggesting insect host specificity. Plant communities unsurprisingly show significant turnover at small spatial scales (i.e. communities situated 0.1-3 km apart show significant turnover and may be tied to ecological niches). Insects show a similar pattern, but the decrease in community overlap is more gradual, suggesting many insects can utilise multiple (possibly closely related) hosts while plants are tied to particular niches. The emergent structure of multiple interaction networks is spatially and temporally invariant, despite high compositional change. However, the internal structure of the networks shows variation (i.e. interactions show spatial and temporal turnover). Seasonal interaction turnover is driven by a turnover in herbivores and by herbivore host switching. Spatially the turnover in interactions is driven by simultaneous turnover in both plants and insects, either suggesting that insects are host specific, or that both groups exhibit parallel responses to environmental gradients. Spatial interaction turnover is also driven by a turnover in plants, showing that many insects can utilise multiple (possibly closely related) hosts and have wider distribution ranges than their host plants. Results point toward insect host specificity, but probably not at the species level, as the primary mechanism structuring insect communities associated with the Restionaceae in the CFR.<br>AFRIKAANSE OPSOMMING: Navorsing wat verband hou met die patrone en meganismes wat insekdiversiteit in the Kaapse Blommeryk (KBR) hou nie pas met dié van plante nie. In hierdie studie neem ek insekmonsters binne een van die dominante plantfamilies (Restionaceae), en gebruik ‘n ruimtelik geneste ontwerp en netwerkanalise om die verbintenis tussen plant- en insekdiversiteit te evalueer. Ek vind plantrykheid voorspel insekrykheid beter as enige omgewingsfaktore. ‘n Omset in in insekgemeenskappe is sterk verbind aan ‘n omset in plantgemeenskappe (beide spesie en filogenetiese) by beide plaaslik en vir die hele streek. Hierdie dui op insekgasheerspesifisiteit. Plantgemeenskappe wys omset teen kort ruimtelike skale (0.1-3 km). Insekte wys ‘n soortgelyke patron, maar die afname in oorvleueling tussen gemeenskappe is meer geredelik. Dit dui dat insek meer as een gasheer kan gebruik, terwyl plante streng tot sekere nisse verbind is. Die ontluikende struktuur van menigde interaksienetwerke wys geen ruimtelike of tydelike variasie nie, ten spyte van hoë gemeenskapsomset. Nietewel, die interne struktuur van die netwerke wys veranderinge (interaksies in netwerke wys omset). Seisonale interaksie-omset kan toegeskryf word aan ‘n omset van herbivore en insekgasheerverandering. Ruimtelike interaksie-omset word toegeskryf aan gelyktydige insek- en plantomset, wat óf deur insekgasheerspesifisiteit veroorsaak word óf deur parallele reaksies tot omgewingsveranderinge. Ruimtelike interaksie-omset word ook deur plantomset beïnvloed, wat aandui sommige insekte kan meer as een gasheer benut en insekte het weier verspreidings as hul gasheer. Resultate dui daarop dat insekgasheerspesifisiteit, maar waarskynlik nie op die spesievlak nie, moontlik die primêre meganisme is wat insekgemeenskappe verbind aan die Restionaceae in die KBR struktureer.

During the insert process when the windings of an electric motor are pushed into the stator slots, some detrimental phenomena can occur that affect the efficiency and life of the motor. To detect these phenomena and optimize the process, a simulation would be useful. An investigation of the possibility to perform a simulation, using an appropriate numerical method for the insert process of distributed windings in a permanent magnet synchronous motor, was performed. During the project, a literature study was carried out to investigate existing methods and key-parameters for the simulation of the process. Explicit finite element method has been shown to be a suitable numerical method for simulating another winding process. An explicit finite element analysis was performed with a simplified model of the stator, the wires, the transmission tool and the needles by using the software Abaqus/CAE. In order to reduce the computational time, beam elements were used to model the wires and the other parts as rigid bodies. The model accounted for example contact and provided numerical results. The result was a suitable model. However, it needs to be developed further.

Bibliography: leaves 231-240.<br>This study focuses on one particular educational partnership i.e. the Partnership established to plan and manage GET inSET, a teacher in-service (Inset) project in the Western Cape. The Partners in this project were the Western Cape Education Department (WCED), four education Non Governmental Organisations (NOOs) and a Funder, the D G Murray Trust (DOMT). My study endeavours to understand the nature of this partnership i.e. exploring and understanding this very complex social process of collaboration. In this dissertation I flrstly present a selection of 'WTiting, which describes different perspectives on the changing roles of the State and Civil Society.

The diamondback moth, Plutella xylostella (L.), is a pest on crucifer crops worldwide, damaging the leaves, florets and seed pods of many crucifers including cabbage, cauliflower, broccoli and canola. It has been controlled using broad-spectrum insecticides, but this has led to a rapid build-up of insecticide resistance. In the Grahamstown area of the Eastern Cape Province, South Africa, diamondback moth showed resistance to cypermethrin (a pyrethroid) on commercially grown cabbages. Therefore it is imperative that other methods of control be adopted, including both cultural control and biological control using parasitoids, and that these are incorporated into an Integrated Pest Management (IPM) programme. The diamondback moth and its parasitoids were monitored weekly from April 1997 to November 1999 at three sites near Grahamstown. One site was a commercial farm with an active insecticide spraying program; the others were unsprayed. Infestation levels were highest during spring (September to November) and autumn (March to May). Nine species of parasitoids were associated with the diamondback moth, with abundances being highest over spring and early summer (September to December). Cotesia plutellae (Kurdjumov) dominated the sprayed site, while the unsprayed sites yielded a complex of parasitoids, including C. plutellae, Diadegma mollipla (Holmgren), Diadromus collaris Gravenhorst and Oomyzus sokolowsldi (Kurdjumov). Parasitism levels ranged between 10 and 90%. There was a large amount of site-to-site and year-to-year variation. Parasitoids were an effective mortality factor against the diamondback moth. The effects of temperature on development and mortality, and of field size and non-crop plants on the distribution of diamondback moth and its parasitoids, were investigated. The results show that high temperatures can depress pest populations, and that the size and surroundings of fields can be manipulated to improve cultural control of the diamondback moth. Suggestions for effective rPM in the Eastern Cape Province include a reduction in insecticide applications, the use of bioinsecticides, for example Bacillus thuringiensis Berliner (Bt) and the encouragement of indigenous parasitoids by planting suitable nectar sources. Cultural control methods are also important and involve removal of cabbage refuse after harvest, management of wild crucifers around cabbage fields, scouting and monitoring the moth population and determining the optimal field size to assist with control by parasitoids.

Interactions between insect herbivores and host plants are fundamental, shaping both ecosystem functions and community structure. One aspect of insect-plant interactions that has received considerable attention recently is the indirect linkages between aboveground and belowground insect herbivores via a shared host plant. To date, the relationship between a maternal insect aboveground and her soil dwelling offspring has been largely overlooked. This study aimed to examine the interactions between the adult insect and soil dwelling larvae of the vine weevil (Otiorhynchus sulcatus) with reference to the preference– performance hypothesis, using an agronomically important host plant, red raspberry (Rubus ideaus). A meta–analysis of aboveground–belowground insect herbivore interactions highlighted that belowground Coleopteran herbivores positively impacted aboveground Homoptera and that general predictions from conceptual models in the literature regarding the direction of interactions between insects were correct, but not statistically significant. In addition it was found that aboveground insect herbivores negatively influenced the survival of belowground herbivores. The preference–performance hypothesis was not supported in the findings for the vine weevil on raspberry. Instead a conflict between larval development and adult egg laying behaviour was observed, with a significant reduction in larval mass recorded when maternal adults fed on the same host plant. Larval mass was decreased by 19% after prior conspecific root feeding, but maternal weevils did not distinguish between plants with and without larvae for oviposition. Significant differences between larval performance (abundances and mass) on the raspberry cultivars Glen Rosa and Glen Ample were not correlated with adult oviposition aboveground. Instead, in some instances, maternal egg laying was correlated with foliar nitrogen content, suggesting that this may be an influential factor in the oviposition behaviour of adult vine weevils. Significant differences seen in larval performance in the laboratory were not reflected in the field, with adult vine weevil populations on Glen Rosa and Glen Ample showing no significant differences in terms of abundance. The findings from this study suggest that mother–offspring relationships in an aboveground–belowground context warrant further consideration. In particular, the identification of potential conflict between mother and offspring highlights another factor influencing aboveground–belowground relationships that could consequently influence terrestrial ecosystems.

Cassava is the main staple crop in Nigeria. Using primary data from four south eastern states in Nigeria, the study assessed the gender impacts of improved cassava varieties. Comparative statistical analysis reveals that total female labor is higher than total male in cassava production, processing and marketing. Women spend more labor days than males for planting, weeding, harvesting, marketing and processing. The total female family labor is higher for adopters of new improved cassava varieties. There is however lower family labor input for both male and female adopters for clearing and plowing which are normally done by men. Significant determinants of female labor supply are number of children in the household, percent of females in the household providing labor on the farm, area under improved cassava varieties and total land area. There is a positive unexpected relationship between total female labor supply and number of children. For each of the decision making variables, there is a significant association between the gender of the spouse and the decision made except for the decision on family labor allocation. Probit results show a significant decrease in the probability that the wife makes the decision for family labor allocation, what inputs to buy and borrowing and traditional cassava income control with adoption. Results indicate that both men and women spend their income on services directly linked to the householdâ s welfare. More than half of the women ranked food as number one.<br>Master of Science

Thesis (MScAgric)--University of Stellenbosch, 2002.<br>ENGLISH ABSTRACT: Lucerne is the most important pasture and fodder crop in the winter rainfall area of South Africa. Various pests are known to cause damage to this crop. The use of the sweep net for monitoring pests is a cheap, easy and quick technique. If the sweep net is suitable for the lucerne pests in South Africa, potential pest status can be determined easily and quickly and the necessary precautionary measures taken to prevent crop losses. From a managerial point of view, it is also important to know the composition of the insect community in order to follow practices in which the number of beneficial insects can be increased and the injurious insects decreased. Therefore a study was done to quantify the use of the sweep net as a survey technique for monitoring pests on established lucerne stands. Insect diversity was also determined to obtain information on the insect families and guilds on lucerne. The redlegged earth mite, due to its importance as a pest, and the Anystis mite, important as a predator, were also included. The sweep net proved to be suitable for the sampling of the main lucerne pests. If a 29 cm diameter sweep net is swiped once per pace for six long paces, twelve systematically chosen sampling units are recommended for the lucerne earth flea and aphids. It is not necessary to differentiate amongst the three aphid species, or between the winged and unwinged aphids. Actual counts should be used instead of absence-presence data. Instead of counting all the insects in a sample, sub-samples can be taken. Operational characteristic curves can be used to determine the risk involved in the decision not to intervene, for example by spraying or grazing. Recommendations for monitoring and the accuracy of control decisions for the redlegged earth mite, Sitona weevil and lucerne butterfly can only be made after threshold values have been determined. The pea aphid, bluegreen aphid and lucerne earth flea showed peaks in their population levels during spring. Peak numbers of the spotted alfalfa aphid occurred during late summer and autumn. The Sitona weevil and lucerne butterfly numbers reached peak levels during late spring and early summer. For all pests population levels were dramatically reduced after grazing or cutting of the plantings. Therefore, these cultivation practices provided good control. The herbivores made up more than 85% of the insect community in lucerne. The largest herbivorous families, in terms of the number of individuals per family, were the Aphididae and Sminthuridae. These two families contain the main lucerne pests, the pea aphid, bluegreen aphid, spotted alfalfa aphid and the lucerne earth flea. The largest predatory family was the Anystidae, represented by the Anystis mite, the most important predator of the red legged earth mite and lucerne earth flea. Another well represented predatory family was the Coccinellidae, containing natural enemies of the aphids. The dryland plantings had a higher percentage of predators than the irrigated lucerne. The most important parasitaids were those in the superfamily Chalcidoidea and in the family Braconidae. The main detritivores were springtails in the suborder Arthropleona, insects in the families Mycetophilidae on irrigated lucerne, and Mycetophagidae on dryland lucerne. The most abundant visitors were in the families Chironomidae, Drosophilidae and Tephritidae. The dryland plantings had a lower percentage of visitors than the irrigated plantings. The number of insect families, as well as the number of individuals per family, was lower at the dryland plantings than at the irrigated plantings. The vast majority of insect families found on lucerne were collected during the one-year sampling period. A lower diversity was found where grazing was more severe, and there was a negative relationship between diversity and evenness.<br>AFRIKAANSE OPSOMMING: Lusern is die belangrikste wei- en voergewas 10 die winterreëngebied van Suid- Afrika. Hierdie gewas word deur 'n verskeidenheid plae aangeval. Die gebruik van die swaainet vir die monitering van plae is 'n goedkoop, maklike en vinnige tegniek. lndien die swaainet geskik is vir die betrokke plae in Suid-Afrika, kan potensiële plaagstatus van die plae dus maklik en vinnig bepaal word en die nodige voorsorgmaatreëls getref word om verliese te voorkom. Vanuit 'n bestuursoogpunt is dit ook belangrik om te weet wat die samestelling van die insekgemeenskap is sodat praktyke gevolg kan word waardeur die getal voordelige insekte verhoog en nadelige insekte verlaag word. Gevolglik is 'n studie uitgevoer om die gebruik van die swaainet te kwantifiseer as 'n monsternemingsmetode vir die monitering van plae op gevestigde lusernstande. Insekdiversiteit is ook bepaal ten einde inligting te bekom oor die insekfamilies en -gildes op lusern. Die lusernerdvlooi en swartsandmyt, vanweë hul belang as plae, en die Anystis-roofmyt, vanweë sy belang as predator, is ook ingesluit. Die swaainet blyk geskik te wees vir die monitering van die. vernaamste lusernplae. Wanneer 'n 29 cm deursnee swaainet vir ses lang treë een keer per tree geswaai word, word 12 sistematies gekose steekproefnemingseenhede vir die lusernerdvlooi en plantluise aanbeveel. Daar hoef nie onderskeid tussen die plantluisspesies en tussen gevleuelde en ongevleuelde plantluise getref te word nie. Daar moet gebruik gemaak word van werklike insektellings en nie van aanwesigheid-afwesigheid data nie. In plaas van om al die insekte in 'n monster te tel, kan submonsters geneem word. Operasionele karakteristieke kurwes kan gebruik word om die risiko verbonde aan die besluit om nie op te tree, deur byvoorbeeld te spuit of bewei nie, te bepaal. Vir die swartsandmyt, Sitona-snuitkewer en lusernskoenlapper moet drempelwaardes eers vasgestel word voordat aanbevelings vir monitering en die akkuraatheid van besluite rakende beheer, gegee kan word. Vir die ertjieluis, blougroenluis en lusernerdvlooi het die bevolkingsvlakke 'n piek in die lente bereik. Die gevlekte lusernluis se piekgetalle was hoofsaaklik in die laat somer en herfs. Die Sitona-snuitkewer en lusernskoenlapper het piekgetalle gehad in die laat lente en vroeë somer. Vir al die plae het bevolkingspieke drasties afgeneem nadat die aanplantings bewei of gesny is. Hierdie verbouingspraktyke blyk dus goeie beheer te verskaf. Die herbivore op lusern het meer as 85% van die insekgemeenskap beslaan. Die grootste herbivoorfamilies, in terme van aantal individue per familie, was die Aphididae en Sminthuridae. Hierdie twee families bevat die vernaamste lusernplae, naamlik die ertjieluis, blougroenluis, gevlekte lusernluis en lusernerdvlooi. Die grootste predatoriese familie was die Anystidae, wat verteenwoordig is deur die Anystis-roofmyt. 'n belangrike predator van die swartsandmyt en lusernerdvlooi. Nog 'n predatoriese familie wat goed verteenwoordig was, was die Coccinellidae, natuurlike vyande van plantluise. Die droëland aanplantings het 'n hoër persentasie predatore gehad as die besproeide lusern. Die belangrikste parasitoïede aanwesig was dié in die superfamilie Chalcidoidea en familie Braconidae. Die vernaamste detritivore was erdvlooie in die suborde Arthropleona, insekte in die families Mycetophilidae by besproeide lusern, en Mycetophagidae by droëland lusern. Die volopste besoekers was lede van die families Chironomidae, Drosophilidae en Tephritidae. Die droëland aanplantings het 'n laer persentasie besoekers gehad as die besproeide lusern. Die aantal insekfamilies, asook die aantal individue per familie, was laer by die droëland aanplantings as by die besproeide aanplantings. Die oorgrote meerderheid insekfamilies wat op lusern voorkom, is gedurende die een jaar opnameperiode waargeneem. 'n Laer insekdiversiteit is gevind waar beweiding strawwer was, en daar was 'n negatiewe verband tussen diversiteit en gelykmatigheid.

Thesis (MSc)--Stellenbosch University, 2015.<br>ENGLISH ABSTRACT: Invasive arthropod predators are one of the largest and most diverse groups of invasive insects in the world. Many are generalist predators, with cosmopolitan distributions due to their use as biological control agents in agriculture. Harmonia axyridis (Coleoptera: Coccinellidae), an invasive arthropod predator species native to Asia, which now has a world-wide distribution. It is considered one of the most successful biological control predator species and is generally considered to be economically beneficial. However, negative effects have recently emerged in agricultural and natural systems. Harmonia axyridis poses a threat to biodiversity as it outcompetes native species for food resources. It can also feed directly on native predatory arthropods that disrupt natural ecosystem processes. Their movement in-and-out of agricultural landscapes may depend on food availability with natural vegetation alongside agricultural areas often utilised for refuge and alternative food resources. This beetle has also been recorded in urban areas. The aim of this study was to determine how the invasive H. axyridis beetle uses the local landscape in the Western Cape province, South Africa, and to determine its threat to native species. I sampled urban landscapes, vineyards, natural vegetation/vineyard edge zones and pristine natural areas for arthropods every second month using a suction sampler. Data collected included the abundance and diversity of H. axyridis, herbivores, local predators and non-Harmonia ladybeetles. Most H. axyridis were collected in urban areas during all sampling periods. Highest abundance was recorded in May and July (winter). This indicates that urban areas were the preferred landscape feature and that these act as ovipositing areas, particularly as larval H. axyridis were also only collected in urban areas. Significantly, vineyards and natural vegetation had very low abundance of H. axyridis, questioning their value as a biological control agent in this region. Harmonia axyridis had a negative effect on the overall local arthropod community, as well as the predator and herbivore guilds, although it was positively correlated with the abundance of non-Harmonia ladybeetles. This suggests that H. axyridis and non-Harmonia ladybeetles are responding to the same resources in these landscapes. A negative correlation found between H. axyridis and the abundance of predators is most likely due to competition for the same resources (e.g. prey items). These negative impacts, along with their negligible value as biological control agents in agriculture, suggest that a programme should be implemented to control this invasive species. More specifically, control should be aimed in urban areas during winter when and where the species aggregates and when larvae are present.<br>AFRIKAANSE OPSOMMING: Geleedpotige roofdiere is een van die grootste en mees diverse groepe van uitheemse insekte in die wêreld. Die meeste is veelsydige roofdiere, met wêreldwye verspreiding te danke aan hul gebruik as biologiese beheer agente in landbou gebiede. Byvoorbeeld, Harmonia axyridis (Coleoptera: Coccinellidae), 'n indringer geleedpotige roofdier spesies inheems aan Asië, het nou 'n wêreldwye verspreiding. Dit word beskou as die mees suksesvolle roofdier spesies wat gebruik word vir biologiese beheer en word oor die algemeen beskou as ekonomies voordelig. Negatiewe effekte was onlangs aangeteken beide in landbou gebiede en natuurlike areas. Harmonia axyridis hou 'n bedreiging in vir inheemse biodiversiteit as dit inheemse spesies uitkompeteer vir voedsel bronne. Dit kan ook direk voed op plaaslike roofsugtige geleedpotiges wat trofiese vlakke ontwrig en uiteindelik, biodiversiteit. Hulle beweging in-en-uit landbou landskappe kan gekoppel word aan die beskikbaarheid van voedsel, en gebruik natuurlike plantegroei langs landbou gebiede dikwels as 'n toevlugs oord en area vir alternatiewe voedsel bronne. Harmonia axyridis word ook in stedelike gebiede aangeteken. Die doel van hierdie studie was om te bepaal hoe die indringer Harlekynkewer die plaaslike landskap gebruik met die fokus op wingerde in die Wes-Kaap provinsie van Suid-Afrika, en tweedens om die bedreiging wat hierdie kewer moontlik vir inheemse spesies te bepaal. Ek het arthropoda in stedelike landskappe, wingerde, natuurlike plantegroei / wingerd rand sones en ongerepte natuurlike areas elke twee maande met behulp van 'n D-vac versamel. Monsters was ontleed deur gebruik te maak van die getalle van H. axyridis, herbivore, plaaslike roofdiere en nie-Harmonia liewenheers kewers. Die meeste H. axyridis was in stedelike gebiede versamel gedurende al die seisoene, maar meeste individue was gedurende Mei en Julie (winter) versamel. Hierdie toon dat stedelike gebiede die voorkeur-landskappe is vir hierdie kewers en dat hierdie gebiede opgetree as eierleggende gebiede, veral omdat larwes van H. axyridis slegs in hierdie gebiede aangeteken was. Wingerde en die natuurlike plantegroei het baie lae getalle H. axyridis gehuisves wat hul waarde as biobeheermiddel bevraagteken. Harmonia axyridis het 'n negatiewe uitwerking op die algehele plaaslike geleedpotige gemeenskappe gehad, asook op die die roofdier en herbivoor gildes, maar hul getalle was positief gekorreleer met die getalle van nie-Harmonia liewenheerskewers. Dit dui daarop dat H. axyridis en nie-Harmonia liewenheerskewers beide reageer op dieselfde hulpbronne in hierdie landskappe. 'n Negatiewe korrelasie was gevind tussen die getalle van H. axyridis en die getalle van ander predatoriese geleedpotiges at waarskynlik te danke was aan mededinging tussen hierdie groepe vir dieselfde hulpbronne (bv prooi). Hierdie negatiewe invloede, asook hul verminderde waarde as biobeheeragente in die landbou, dui daarop dat 'n program in werking gestel moet word om hierdie indringerspesies te beheer. Meer spesifiek, beheer moet gedurende die winter en in stedelike gebiede geskied, waar en wanneer hierdie spesie op sy volopste is en waar larwes teenwoordig is.

Doctor Educationis<br>This thesis represents the outcome of an interaction between a participating "outsider" and a group of teachers during which a continued dialogue between theory and practice was pursued. The goal was to enhance the quality of teaching practice in a specific situation on the one hand and on the other, gain deeper insight into the theoretical aspects which have a bearing on classroom practice. The research project was initially started in response to teachers' request for help with the teaching of Afrikaans first language to learners whose home language was Afrikaans, but who did not make satisfactory progress in Teachers from four schools in the Richtersveld, a far-off region in the Northern Cape, one of the nine provinces of South Africa, joined the INSET project and participated in a hands-on language programme in which a different approach from the traditional teaching and learning model was advocated. The innovative programme focused on an integrated approach to the teaching and learning of reading and writing as meaning-making activities. The research was carried out within a qualitative research framework in which participants not only had to carry out specific innovative learning tasks, but had to reflect on the value of their actions with a view to become change agents who would facilitate learning in such a manner that their pupils would also develop into reflective agents who would be able to take charge of their particular life world. The project experience was shared through a narrative which required of readers to take a stance since they had to make meaning of the identified themes and motifs which gradually emerged. Some of the major themes which, in my view, developed were: that successful communication between stakeholders in die teaching and learning event is a prerequisite for successful learning. Language is a social construct, but is the central medium of communication, therefore, all participants should understand the operative "rules" of communication in a specific learning context. All pupils in multi-lingual classes should be in a position where their life chances, not only their life-styles, are enhanced. Teachers and pupils should be sensitised to the fact that they have to re-invent their own culture on a continuous basis in order to meet the demands set by the dynamic nature of present-day culture norms as they manifest in reality. Teachers in an innovative INSET programme such as the GGLESIP project should be willing to change their thinking about what learning entails. This presupposes a change of attitude and a changed concept of leadership which is different from mere classroom management. In this particular teaching and learning situation it has become clear that INSET, like all other teaching and learning activities is norm oriented.

Insects can cause economic and environmental damages by transmitting bacterial pathogens to plants, making the use of control and prevention measures imperative. On the other hand, methods aimed at preventing crop pests’ outbreaks, such as tilling and insecticide applications, pose a threat to human and ecosystems health. Innovative and more sustainable control methods are therefore urgently needed to address farmers’ needs and preserve ecosystem services provided by biodiversity. Biotremology is an emerging science that studies the substrate-borne vibrational signals emitted by insects to communicate and interact with their others in the environment. As many insect pests rely on these signals to communicate, their behaviour can be manipulated by transmitting vibrations to the substrate where they thrive. Vibrational signals can, for instance, interfere with target’s behaviours such as mating, feeding, and residence time on the plant, and can therefore support integrated pest management strategies alternative to insecticides. In this work, I investigated the mating behaviour and vibrational communication of two insect vectors having an important economic impact: Philaenus spumarius (Hemiptera: Aphrophoridae) and Bactericera cockerelli (Hemiptera: Triozidae). I also provided novel insights regarding the vibrational manipulation of their behaviour. I characterised the sexual behaviour and associated vibrational signals of the meadow spittlebug P. spumarius, and I described other intraspecific interactions. I evaluated the correlation between the female signalling activity and development of the reproductive organs, suggesting that a vibrational mating disruption could be effective only if applied from the onset of egg maturation, which triggers the female proceptivity (from August onwards). Besides gathering behavioural data, I used occupancy models to estimate P. spumarius presence and detection probability in Trentino (Northern Italy), a rarely deployed approach to study insect distribution. Site covariates impacted P. spumarius detectability, suggesting that spittlebug presence can be overlooked if detection is not considered. As plant composition influences the presence and abundance of the spittlebug, I studied the association between P. spumarius and its host plants. Such information can support monitoring programs and control strategies aimed at reducing P. spumarius population in crops of interest by shaping the plant composition of the ground cover. After investigating the behaviours and the ecology of the spittlebug, I attempted to disrupt its feeding activity using vibrations, opening the gates for future research. In this regard, I combined for the first time biotremology with the Electrical Penetration Graph (EPG) technique. The tomato potato psyllid B. cockerelli is an important threat to New Zealand crops. Besides the characterisation of the pair formation process and associated vibrational signals, I used vibrations to disrupt mate finding by transmitting vibrations to the host plant. Given that the stimulus attracted male psyllids at small scale, this strategy is a feasible approach that could be implemented for use in fields and greenhouses. In this way, an innovative trapping and mating disruption device could join the farmers’ toolbox for monitoring and controlling B. cockerelli. In conclusion, I provided new information regarding the ethology of two insect vectors and suggested that there is room for applied biotremology to support sustainable management strategies.

Insects can cause economic and environmental damages by transmitting bacterial pathogens to plants, making the use of control and prevention measures imperative. On the other hand, methods aimed at preventing crop pests’ outbreaks, such as tilling and insecticide applications, pose a threat to human and ecosystems health. Innovative and more sustainable control methods are therefore urgently needed to address farmers’ needs and preserve ecosystem services provided by biodiversity. Biotremology is an emerging science that studies the substrate-borne vibrational signals emitted by insects to communicate and interact with their others in the environment. As many insect pests rely on these signals to communicate, their behaviour can be manipulated by transmitting vibrations to the substrate where they thrive. Vibrational signals can, for instance, interfere with target’s behaviours such as mating, feeding, and residence time on the plant, and can therefore support integrated pest management strategies alternative to insecticides. In this work, I investigated the mating behaviour and vibrational communication of two insect vectors having an important economic impact: Philaenus spumarius (Hemiptera: Aphrophoridae) and Bactericera cockerelli (Hemiptera: Triozidae). I also provided novel insights regarding the vibrational manipulation of their behaviour. I characterised the sexual behaviour and associated vibrational signals of the meadow spittlebug P. spumarius, and I described other intraspecific interactions. I evaluated the correlation between the female signalling activity and development of the reproductive organs, suggesting that a vibrational mating disruption could be effective only if applied from the onset of egg maturation, which triggers the female proceptivity (from August onwards). Besides gathering behavioural data, I used occupancy models to estimate P. spumarius presence and detection probability in Trentino (Northern Italy), a rarely deployed approach to study insect distribution. Site covariates impacted P. spumarius detectability, suggesting that spittlebug presence can be overlooked if detection is not considered. As plant composition influences the presence and abundance of the spittlebug, I studied the association between P. spumarius and its host plants. Such information can support monitoring programs and control strategies aimed at reducing P. spumarius population in crops of interest by shaping the plant composition of the ground cover. After investigating the behaviours and the ecology of the spittlebug, I attempted to disrupt its feeding activity using vibrations, opening the gates for future research. In this regard, I combined for the first time biotremology with the Electrical Penetration Graph (EPG) technique. The tomato potato psyllid B. cockerelli is an important threat to New Zealand crops. Besides the characterisation of the pair formation process and associated vibrational signals, I used vibrations to disrupt mate finding by transmitting vibrations to the host plant. Given that the stimulus attracted male psyllids at small scale, this strategy is a feasible approach that could be implemented for use in fields and greenhouses. In this way, an innovative trapping and mating disruption device could join the farmers’ toolbox for monitoring and controlling B. cockerelli. In conclusion, I provided new information regarding the ethology of two insect vectors and suggested that there is room for applied biotremology to support sustainable management strategies.

Thesis (MSc)--Stellenbosch University, 2015.<br>ENGLISH ABSTRACT: The present global biodiversity crisis is characterized mostly by loss of species due to habitat destruction but there other major threats – notably invasive alien species. The term “biodiversity hotspot” has been coined to emphasize areas for conservation prioritization – areas that have high biodiversity under threat from habitat destruction, invasive species, etc. The Cape Floristic Region (CFR) in the Western Cape (WC) Province of South Africa has the highest biodiversity of all Mediterranean-type climate regions globally and is classified among global biodiversity hotspots. The CFR, a Mediterranean-type climate heathland with a naturally high fire frequency, faces threat from transformation by development, disturbed (increased) fire frequencies and intensities, and invasive organisms, most notably invasive trees. Such threats disturb keystone species and keystone processes including insect pollinator assemblages and associated insect flower visitation webs and frequencies. Invasive pines are a serious threat to insect flower visitation as pine trees (Pinus spp.) shade out much indigenous vegetation in the CFR. Little is known of their long-term effects on insect flower visitors and vegetation recovery in post-pine restoration and recovery areas after such trees are removed. I investigated the recovery of vegetation and the most important insect pollinator, bees, after the removal of pines by fire and passive recovery in a CFR valley in the Western Cape. In 1999, a wildfire burned much of the WC Limietberg Nature Reserve along with an adjacent pine tree forestry stand - which was then left to recover, providing an ideal opportunity to investigate the enduring effects of pine afforestation in the CFR. In two data chapters, I compared the post-fire passive recovery of vegetation (Chapter 2) and bee diversity (Chapter 4) in areas which had previously been planted with pines vs. those which had contained natural fynbos. To improve on sampling methodology, I conducted an experiment that demonstrated the Observer Effect in bee sampling with a sweep net (Chapter 3), and I developed a novel sampling device (Chapter 5) for insect flower visitors. Sampling of vegetation and bee diversity was conducted in a paired sampling design, where fynbos (Natural) sub-sites were paired with sub-sites which had previously been afforested with pines (Post-Pine Recovery; PPR) and the two sub-sites were separated by a distinct, linear boundary (Natural/PPR boundary). Sampling was conducted along transects parallel to the boundary and extending in both directions from the boundary into the Natural and in the opposite direction into PPR sub-sites. Five transects were positioned at 3, 10, 20, 30, and 40 m from the boundary (Ecotone) and three were positioned at 60, 80, and 100 m from the boundary (Deep). In Chapter 2, I found that natural sub-sites consistently had higher total plant species abundance and species richness than PPR sub-sites. Approximately two thirds of plant species were more abundant in Natural sub-sites than in PPR sub-sites. There was no significant correlation in species richness or abundance with distance from the Natural/PPR boundary. Some genera are cautiously indicated as having lower success in recovery after pine afforestation: Erica spp., Restio spp., Hypodiscus spp. while Helichrysum spp. is also tentatively indicated to recover well in PPR sub-sites. Soil disturbance and concomitant disruption of normal ecosystem functions, including pollination, is indicated as a probable reason for disruption of plant recovery. In Chapter 3, sweep netting methodology was tested for the Observer Effect. A noticeable increase in bee visitation frequency to a common generalist plant species in bloom, Metalasia densa, was correlated with longer waiting periods after I stopped moving indicating the presence of an Observer Effect. This suggests that sweep netting for bees should only be commenced after a waiting period of five minutes during which the sweep netter is motionless. In Chapter 4, using a flight-intercept modified pan trap, I compared bee species richness and bee species abundance across different seasons and in both mass-flowering and sparser flower patches. There was no significant difference in bee species richness between Natural and PPR sub-sites. All bee species, except one complex, were more abundant in Natural sub-sites. Nearly two thirds of all bee species (n=37 of 56) caught with sweep netting and the modified pan trap are undescribed species. Similar to the vegetation, the effects of soil disturbance as a result of decades of pine forest shading and pine forest litterfall followed by an unusually hot pine forest fire are indicated as the most likely reasons for lower bee abundance in PPR sub-sites. This is due to the difficulty associated with viable nest establishment and suitable pollen and nectar forage availability in disturbed areas. In Chapter 5, the newly developed Pan and Flight Intercept Combination (PAFIC) trap’s design, pilot testing, and comparison with the traditional pan trap is discussed. A preliminary test suggests that the PAFIC trap is more efficient (with higher abundance) than the traditional pan trap. In Chapter 6, I discuss the implications of the disturbance of pine forestry and unusual pine fire to plant species and bee species assemblages. Bee-pollination webs in PPR sub-sites are indicated as being substantially simpler than those in Natural areas as well as compositionally different. The recovery of pollination as a keystone process in post pine-afforestation areas faces a substantial challenge given the disturbance to soil that decades of pine afforestation followed by pine forest fire can cause. Some suggestions are made for the restoration of fynbos areas recovering from pine afforestation including a discussion of augmenting re-vegetation measures (fynbos seed dispersal and seedling planting) with methods of restoring of healthy pedogenesis, epigaeic arthropod communities, and fynbos seedbanks.<br>AFRIKAANSE OPSOMMING: Die huidige globale biodiversiteit krisis is gekenmerk meestal deur die verlies van spesies as gevolg van die vernietiging van habitat. Maar daar is ook ander groot bedreigings – veral merkbaar indringerspesies. Die term “biodiversiteit brandpunt” is geskep om gebiede vir bewaring prioritisering te beklemtoon - gebiede wat 'n hoë biodiversiteit bevat wat bedreig word deur die vernietiging van habitat, indringerspesies, ens. Die Kaap Floristiese Streek (KFS) in die Wes-Kaap (WK) Provinsie van Suid-Afrika het die hoogste biodiversiteit van alle Mediterreense tipe klimaat streke wêreldwyd, en is onder die globale biodiversiteit brandpunte geklassifiseer. Die KFS, 'n Mediterreense-tipe klimaat heideveld met 'n natuurlike hoë brand frekwensie, word bedreig as gevolg van transformasie deur ontwikkeling, versteurde (verhoogde) vuur regimes, en indringer organismes, veral indringerbome. Sulke bedreigings versteur hoeksteen spesies en die hoeksteen prosesse, insluitende insek bestuiwer samestelling en verwante insek blom besoekings webbe en frekwensies. Indringer dennebome (Pinus spp.) is 'n ernstige bedreiging vir insek blom besoeking want dennebome verskaf skaduwee aan baie inheemse plantegroei in die KFS. Min is bekend oor die langtermyn effekte op insek blom besoekers en plantegroei restorasie na denneboom verwydering en restorasie gebiede na sodanige bome verwyder word. Ek ondersoek die restorasie van plantegroei en die belangrikste insek bestuiwer, bye, na die vernietiging van dennebome deur vuur en passiewe herstel in 'n KFS vallei in die Wes-Kaap. In 1999 het'n veldbrand baie van die WK Limietberg Natuurreservaat saam met 'n aangrensende denneboom bosbouplantasie gebrand - wat toe gelaat is om te herstel via intermediêre suksessie na inheemse fynbos plantegroei. Dit bied 'n ideale geleentheid om die blywende gevolge van denneboom aanplanting in die KFS te ondersoek. In twee data hoofstukke, vergelyk ek die passiewe herstel van plantegroei na ‘n brand (Hoofstuk 2) en by diversiteit (Hoofstuk 4) in gebiede wat voorheen geplant is met dennebome teenoor diegene wat natuurlike fynbos vervat het. Om te verbeter op steekproefmetodiek, het ek 'n eksperiment onderneem wat demonstreer hoe die Waarnemer Effek by monsterneming met 'n vee-net beïnvloed (Hoofstuk 3), en het ek 'n nuwe monsterneming toestel ontwerp (Hoofstuk 5) vir insek blom besoekers. Monsterneming van plantegroei en by diversiteit is uitgevoer in 'n gegroepeerde steekproef ontwerp, waar fynbos (Natuurlik) sub-terreine gegroepeer is met sub-terreine wat voorheen aangeplant was met dennebome (Na Denneboom Verwydering Herstel; NDVH) en die twee sub-terreine is geskei deur 'n duidelike, lineêre grens (Natuurlik / NDVH grens). Steekproefneming is gedoen langs transekte parallel tot die grens en versprei in albei rigtings van die grens tot binne die natuurlike fynbos en in die teenoorgestelde rigting tot binne NDVH sub-terreine. Vyf transekte is geposisioneer binne 50 m van die grens (Oorgang sone) en drie is ver geplaas van die grens (Diep). In Hoofstuk 2 het ek gevind dat natuurlike sub-terreine konsekwent hoër totale getal plant individue en spesierykheid as NDVH sub-terreine gehad het. Ongeveer twee derdes van plantspesies was meer volop in natuurlike sub-terreine as in NDVH sub-terreine. Daar was geen beduidende korrelasie in spesierykheid of totale hoeveelheid plant individue met betrekking tot afstand van die Natuurlike /NDVH grens. Sommige genera word versigtig aangedui as met laer sukses in die restorasie terreine na denneboom aanplanting: Erica spp., Restio spp., Hypodiscus spp. terwyl Helichrysum spp. voorlopig aangedui is as goed herstel in NDVH sub-terreine. Grondversteuring en gepaardgaande ontwrigting van normale funksionering van die ekosisteem, insluitend bestuiwing, word aangedui as 'n waarskynlike rede vir die ontwrigting van die herstel van plantegroei. In Hoofstuk 3 is vee-net metodologie getoets vir die Waarnemer Effek. 'N merkbare toename in by besoeking frekwensie van 'n algemene plantspesie in blomtyd, Metalasia densa, is gekorreleer met langer wagtydperke nadat ek gestop het om te beweeg, en dui dus op die teenwoordigheid van 'n Waarnemer Effek. Dit dui daarop dat die vee-net vir bye eers gebruik moet word na 'n wagtydperk waartydens die waarnemer bewegingloos verkeer. In Hoofstuk 4, met behulp van 'n vlug-onderskep gewysigde pan lokval, het ek by spesierykheid en totale by hoeveelheid vergelyk oor verskillende seisoene en in beide massa-beblomde en yler blom kolle. Daar was geen beduidende verskil in by spesierykheid tussen natuurlike en NDVH sub-terreine. Alle by spesies, behalwe een spesie kompleks, was meer volop in natuurlike sub-terreine. Byna twee derdes van alle by spesies (n = 37 van 56) gevang met vee-nette en die van die gewysigde pan lokvalle is onbeskryfde spesies. Soortgelyk aan die plantegroei, is die gevolge van grondversteuring as gevolg van dekades van denneboom bos skadu en denneboom bos blaar afval gevolg deur 'n buitengewoon warm denneboom bos brand as die mees waarskynlike redes vir laer by hoeveelheid in NDVH sub-terreine aangedui. Dit is as gevolg van die probleme wat verband hou met lewensvatbare nes vestiging en geskikte stuifmeel en nektar voer beskikbaarheid in versteurde gebiede. In Hoofstuk 5 is die nuut ontwikkelde Pan en Vlug Onderskep Kombinasie (PEVOK) lokval ontwerp, aanvanklike toetsing, en vergelyking met die tradisionele pan lokval bespreek. 'N Voorlopige toets dui daarop dat die PEVOK lokval meer doeltreffend (met 'n hoër oorvloed) is as die tradisionele pan lokval. In Hoofstuk 6 bespreek ek die implikasies van die versteuring van denneboom bosbou en ongewone denneboom vuur met betrekking tot plant spesies en by spesies samestelling. By-bestuiwing webbe in NDVH sub-terreine word aangedui as wesenlik eenvoudiger as dié in natuurlike areas asook verskillend in samestelling. Die herstel van bestuiwing as 'n hoeksteen in na denneboom-aangeplante gebiede staar 'n aansienlike uitdaging in die gesig, gegee die versteuring van grond wat dekades van denneboom aanplanting gevolg deur denneboom bos brand kan veroorsaak. Sommige voorstelle is gemaak vir die herstel van fynbos gebiede wat herstel van denneboom aanplanting, insluitend 'n bespreking van die aanvulling van plantegroei hervestiging maatreëls (fynbos saadverspreiding en saailinge plant) met die metodes van die herstel van 'n gesonde pedogenese, bogrondse geleedpotige gemeenskappe, en fynbos saadbanke.

Thesis (PhD)--Stellenbosch University, 2015.<br>ENGLISH ABSTRACT: Understanding how divergent selection results in the evolution of reproductive isolation (i.e. speciation) is an important goal in evolutionary biology. Populations of herbivorous insects using different host plant species can experience divergent selection from multiple selective pressures which can rapidly lead to speciation. Restio leafhoppers are a group of herbivorous insect species occurring within the Cape Floristic Region (CFR) of South Africa. They are specialised on different plant species in the Restionaceae family. Throughout my thesis I investigated how bottom-up (i.e. plant chemistry/morphology of host plant species) and top-down (i.e. predation and competition) factors drive specialisation and divergence in restio leafhoppers. I also investigated interspecific competition as an important determinant of restio leafhopper community structure. In chapter 2 I quantified host specificity of restio leafhopper species within a local community for 24 months. I found that restio leafhopper species are highly host specific and potentially synchronised with the growth phases of their host plants. In chapter 3 I used a network metric, modularity, to determine whether host plant partitioning in a restio leafhopper community is non-random (i.e. driven by a deterministic process). This metric allows the identification of the components underlying host plant partitioning (modules). I then performed experiments to show that modules, and therefore host plant partitioning, can mostly be explained by preference and performance relationships (i.e. bottom-up factors). In chapter 4 I used null models to test whether niche partitioning in restio leafhopper communities is a general pattern across the landscape. I found non-random niche partitioning, which results from strong host specificity, in all investigated restio leafhopper communities. In addition, I performed binary host choice experiments in the presence and absence of interspecific competition, but found no evidence that interspecific competition narrows host preferences. These findings suggest that host specificity, the cause of niche partitioning, is likely shaped over evolutionary time. Sampling multiple interaction networks across the CFR, in chapter 5, I tested whether restio leafhopper populations are more host specific in species rich communities and regions in the CFR than in species poor communities and regions. I found no positive relationship between restio leafhopper species richness and host specificity at any scale. These findings suggest that specialisation is not driven by interspecific competition. In chapter 6 I investigated host shifts in Cephalelus uncinatus. C. uncinatus has a broader distribution than any single restio species that it can use; suggesting that host plant related divergence may result from geographic range expansion. I found that allopatric and parapatric populations, but not sympatric individuals, using different host plants have divergent host preferences. I also found evidence for morphological divergence in traits related to predator avoidance in population pairs that exhibit divergent host preferences. My findings emphasise the importance of both bottom-up and top-down factors, with the exception of interspecific competition, as determinants of specialisation and divergence in restio leafhoppers. I find no evidence that interspecific competition is an important force structuring restio leafhopper communities. Instead, strongly niche partitioned community structure appears to emerge from the speciation process.<br>AFRIKAANSE OPSOMMING: Die wyse waarop uiteenlopende seleksie lei tot die evolusie van seksuele isolasie (n.l. spesiasie) is ‘n belangrike vraag in evolutionêre biologie. Plantetende insekpopulasieses wat verskillende gasheerplante gebruik kan onder uinteenlopende veelvoudige seleksie wees en vinnig spesiasie ondergaan. Restio-blaarspringers is ‘n groep plantetende insekspesies wat gespesialiseerd is op verskillende plantspesies in die restio familie. In my tesis ondersoek ek die onder-op (n.l. plantchemie en morfologie) en bo-af seleksiekragte (n.l. predasie en kompetisie) wat lei tot gasheerspesialisasie en -spesiasie in restio-blaarspringers. Ek ondersoek ook die belangrikheid van tussen-spesieskompetisie in gemeenskapsorganisasie. In hoofstuk 2 het ek gasheerspesialisasie gekwantifiseer in ‘n klein restio-blaarspringergemeenskap oor 24 maande. Ek het gevind dat restio-blaarspringers hoogs gasheerspesifiek is en moontlik met die groeifase van hul hoofgasheerplante gesinchroniseerd is. Ek het in hoofstuk 3 ‘n netwerkmetriek, modulariteit, gebruik om te bepaal of restio-blaarspringers se gasheerverdeling nie-stokasties is (n.l. deur deterministiese prosesse veroorsaak is). Hierdie metriek laat ‘n mens toe om die komponente van gasheerverdeling (modules) te identifiseer. Deur middel van eksperimente het ek bepaal dat modules, en dus gasheerverdeling, deur gasheervoorkeur en prestasie (onder-op prossesse) verduidelik kan word. In hoofstuk 4 het ek ondersoek of gasheerverdeling algemeen is. Ek het deur middel van nulmodelle gewys dat gasheerverdeling algemeen is en veroorsaak is deur sterk gasheerspesifiekheid. Ek het ook voorkeureksperimente uitgevoer in die teenwoordigheid en afwesigheid van tussen-spesies kompetisie. Hier het ek geen teken gevind dat huidige tussen-spesies kompetisie gasheervoorkeur beïnvloed nie. My bevindinge in hierdie hoofstuk stel dus voor dat spesialisasie, die oorsaak van gasheerverdeling, oor evolutionêre tyd gevorm word. In hoofstuk 5 het ek ondersoek of populasies van restio-blaarspringers meer gasheerspesifiek is in restio-blaarspringerspesies ryke gemeenskappe en streke as populasies in spesies-arm gemeenskappe en streke. Ek het geen positiewe korrelasie tussen spesiesrykheid en gasheerspesialisasie gevind nie. Dit dui daarop aan dat gasheerspesialisasie, en dus gasheerverdeling, nie deur tussen-spesies kompetisie veroorsaak word nie. In hoofstuk 6 het ek gasheerplantgekoppelde divergensie ondersoek in Cephalelus uncinatus. C. uncinatus se verspreiding is breër as enige restio-spesies wat dit kan gebruik. Dit stel voor dat verspreidingvergroting gasheerverskuiwing mag veroorsaak. Ek het gevind dat populasies wat verskillende plante in allopatrie en parapatrie gebruik uiteenlopende gasheerkeuses maak, maar insekte wat verskillende plante in sympatrie gebruik wys nie ontwrigtende gasheerkeuses nie. Die populasies wat uiteenlopende gasheerkeuses getoon het, het ook verskillende morfologiese teen-predasie eienskappe getoon. Dit dui daarop aan dat predasie belangrik mag wees vir spesiasie in restio-blaarspringers. Die bevindinge van my tesis dui daarop aan dat beide onder-op en bo-af seleksie belangrik is vir gasheer-spesialisasie in divergensie. Nietemin, tussen-spesies kompetisie is nie ‘n belangrike bron vir spesialisasie, divergensie of gemeenskapsorganisasie nie. Gemeenskapsorganisasie is klaarblyklik slegs ‘n gevolg van die spesiasie proses.

Les interactions interindividuelles permettent la transmission de l’information, la dispersion des pathogènes et la mise en place des comportements dans une population. Cette thèse a permis d’évaluer l’influence des interactions sociales sur le succès de fondation colonial des différents reproducteurs de deux termites européens, l’invasif Reticulitermes flavipes et le natif R. grassei. Les résultats révèlent (i) un meilleur succès de fondation des reproducteurs primaires de R. flavipes, (ii) une organisation biparentale des soins aux jeunes toutes espèces confondues et (iii) une communication et des soins aux oeufs propres aux caractères invasif et natif des espèces d’étude. Pour finir, (iv) une meilleure survie et communication a été observée dans les colonies fondées avec reproducteurs secondaires tandis (v) qu’une communication supérieure et une survie moindre sont observées pour R. flavipes. Les origines évolutives de l’organisation biparentale et des variations de succès de fondations sont discutées<br>Individual interactions permit information transmission, pathogen dispersion and shape behavioral strategies in a population. This thesis has permit to explore the influence of social interactions on the colonial foundation success of two European termites, the invasive Reticulitermes flavipes and the native R. grassei. The overall results revealed (i) a better foundation success of primary reproductives of R. flavipes, (ii) a biparental organisation of parental care in both species (iii) a level of communication and egg care reflecting native and invasive status of the two species studied. To finish, (iv) better survival and communication rates were observed in colonies founded with secondary reproductives than in colonies without any and (v) a better communication rate and a weaker survival rate for R. flavipes foundations with or without secondary reproductives. Evolutive origins of biparental care and of the variations of foundation success observed are discussed

The interaction between farmers, agricultural scientists and extension workers is sometimes overlooked in agricultural entomology. In an attempt to respond to this reality this study examines some foundation of this interaction in relation to the pest management practices of subsistence and small-scale farmers and also highlights the problems that might arise in the implementation of IPM. Problems involving pests occurrence; language barriers; beliefs, knowledge and perception about insects, and visual literacy are examined. The thesis has a two-fold focus, firstly the study of pests on cabbages of subsistence farmers in Grahamstown and secondly a broader focus on other aspects such as cultural entomology, perception of insects and visual literacy specifically in relation to Xhosa speaking people in the Eastern Cape. The most important crop for emergent farmers in the Eastern Cape are cabbages, which have a variety of pests of which diamondback moths and are the most important. Traditional pest management practices tend to influence the development of IPM programmes adopted by these farmers. Eastern Cape farmers apply periodic cropping systems, which had an effect on the population densities of diamondback moth (DBM), other lepidopteran pests and their parasitoids. Considering the maximum population densities of DBM, which were 0.2 - 2.9 larvae/plant, there were no major pest problems. The availability of parasitoids, even in highly disturbed and patchy environments, showed good potential for biological control. Since some extension officers cannot speak the local farmers’ language, a dictionary of insect names was formulated in their language (isiXhosa) to assist communication. Response-frequency distribution analysis showed that the dictionary is essentially complete. The literal translations of some names show that isiXhosa speakers often relate insects to people, or to their habitat or classify them according to their behaviour. Farmers from eight sites in the Eastern Cape were interviewed regarding their knowledge and perception of insect pests and their control thereof. To some extent, farmers still rely on cultural control and have beliefs about insects that reflected both reality and superstition. There is no difference between the Ciskei and Transkei regions regarding insect-related beliefs. Farmers generally lack an understanding of insect ecology. There is a need for farmers to be taught about insects to assist with the implementation of IPM. Leftover pesticides from commercial farms or detergents are sometimes used to manage the pests. When training illiterate or semi-literate farmers, it is important to understand their media literacy so as to design useful graphic and object training media. Generally farmers showed that they either understand graphic or object media depending on the features of the insects being looked at. These findings are discussed with regard to the potential development of IPM training material for subsistence and small-scale farmers in a community.

The genus Erica is the most species rich in the Cape Floristic Kingdom, yet there are limited data on the various flower-pollinator interactions and breeding systems for the majority of these species. Until recently research has focussed on predictive floral traits, including flower shape, length of corolla and corolla opening to identify likely pollinators in this genus. Field observations provide an empirical test of such predictions. This study investigated three species of Erica and compared their pollination and breeding systems and floral biology. Research, including field experiments and pollinator observations was undertaken in the Vogelgat Private Nature Reserve, Maanschynkop Nature Reserve and Boskloof farm in the vicinity of Hermanus in the Western Cape Province of South Africa. Field observations were conducted to determine what flower- visitor interactions occurred, while nectar volumes and sugar concentrations were measured to determine the value of the reward to the different visitors. Selective exclusion and breeding system experiments were carried out to determine whether these Erica species were capable of autonomous self-fertilization or whether they are pollinator dependent for breeding success. The unusual morphology of Erica lanuginosa suggested rodent-pollination. Field observations, including photographs of visits to plants in the field, the presence of pollen in scat sample and selective exclusion and breeding system experiments identified rodents, primarily Acomys subspinosus to be the primary pollinator. Long-proboscid flies of the family Nemestrinidae were found, on the basis of field observations to be responsible for pollination of the endemic Erica aristata. This was supported by with nectar volume and sugar concentration samples which are consistent with other long-proboscid fly-pollinated plant species. Selective exclusion and breeding system experiments undertaken confirmed that Erica aristata required a pollinator to set seed. Observations and breeding trials revealed bird-pollination in Erica sessiliflora. Nectar volume and sugar concentrations in Erica sessiliflora were in line with other sunbird-pollinated plant species, providing the necessary rewards for sunbirds visiting this species. Specialised pollination by single pollinators was found in all three species and results from breeding system experiments show that out-crossing is important. Further research into pollinator-flower interactions in the genus Erica is necessary, not least to understand more fully the conservation importance of specific pollinators.

Identifying homologous genes, that is genes from a common ancestor, is important in comparative genomic studies for understanding gene annotation and the predicted function of a gene. Several pieces of software, of which the most well-known is BLAST, have been developed for identifying homologues, but this can be challenging in non-model organisms where sometimes poor quality of genome assemblies and lack of annotation make it difficult to robustly identify homologues. The aim of this project was to build a bioinformatic framework for homology detection using genomes from non-model organisms. The approach developed used genome annotations, annotated polypeptide sequences and genome assembly sequences to detect homologous genes.The framework was applied to identify Drosophila melanogaster homologous wing development genes in the genomes of nine other insect species with the aim to understand the evolution of loss of wings. To identify changes related to wing loss, the homologous protein sequences obtained were aligned and phylogenetic trees were built from them. The aim of creating the multiple protein alignments and phylogenetic trees was to shed light on whether changes in gene sequences can be related to presence or absence of wings. From the set of 21 candidate wing development genes identified with literature and subsequent database searches, I tested eight and was successful in identifying homologues for all of them in eight of the 10 in sectgenomes. This was done using a combination of text searches in genome annotations, searches with Exonerate v. 2.4.0 alignment program in annotated polypeptide sequences and in genome assemblies. The eight genes chosen for testing the framework were based on initial finding of putative homologues in the eight insect genomes when using the first two steps of the framework. For the set of homologous wing development genes examined I was not able to identify any conclusive pattern of potential protein coding changes that correlated with loss of wings in these species. Improvement to the current pipeline could include using query sequences from closer relatives of the 8 test species than D. melanogaster and, of course, testing of the remaining wing development genes as well as further literature study of wing development genes. Together these could improve future studies on the evolution of wing loss in insects.

Fleas are one of the major external parasites affecting free range chickens, causing irritation, tissue damage, blood loss and toxicosis which in turn affect quality and quantity of meat and egg production. There are many commercial insecticides available that are effective against fleas. These commercial insecticides have, however become expensive to most resourcelimited farmers and therefore unaffordable, causing farmers to seek low cost alternatives. This study was conducted to document, determine the existence of external parasites in freerange chickens and validate the alternative remedies used in controlling free-range chicken fleas by resource-limited farmers. A questionnaire survey was used to collect data on external parasites of free-range chickens and ethno-veterinary control remedies used by resourcelimited farmers to control these parasites at Amatola basin, in Eastern Cape, South Africa. Resource-limited farmers perceived that mites (79.6%), fleas (64.5%), lice (10.8%) and ticks (6.5%) were problematic parasites of chickens. To control these parasites, resource-limited farmers commonly use ash (28%) madubula (13% carbolic acid) (26.7%), Jeyes fluid (13% carbolic acid) (10%), paraffin (8.4%), used engine oil (2.8%), plants Tagetes minuta, Clutia pulchella, Calpurnia aurea (5.2%) and a few (4.2%) used commercial drugs Karbadust (Carbarly 5%) and mercaptothion 5%. About 7.5% of the respondents used neither of the remedies. To confirm the farmers’ perception on problematic external parasites of free-range chickens a diagnostic survey was conducted. Fifty free-range chickens were randomly selected and examined for external parasites. About 96% of the free-range chickens examined harboured at least one species of external parasites. Fleas (Echidnophaga gallinacea) (50.7%) were the most prevalent followed by lice, Menopon gallinae (12.4%); Menacanthus stramineus (5.3%) and Knemidocoptes mutans (0.57%). Given that Jeyes fluid, used engine oil, paraffin, C. aurea, C. pulchella and T. minuta were mainly used in controlling these parasites, it was important to determine the potential dermal irritant effects of these plants. A dermal irritant effect test was, therefore, conducted using a rat model. Forty eight rats, with parts of the backs shaven, were used to screen the materials for irritation. All the materials tested did not cause any visible skin irritation on rats (p>0.05). Regarding that ethnoveterinary materials were non irritant on rat skin in vitro repellency and contact bio-assay models were used to assess the insecticidal properties of Tagetes minuta, Calpurnia aurea, Clutia pulchella, used engine oil, paraffin and Jeyes fluid on fleas. For the in vitro bioassay T. minuta and Jeyes fluid at 100% concentration demonstrated a repellency level of 76 and 83%, respectively. Tagetes minuta was the most effective among plant materials (p<0.05). Clutia pulchella, C. aurea, used engine oil and paraffin showed insignificant repellency (p>0.05). For the contact bio-assay, C. pulchella, C. aurea and T. minuta at a concentration of 100% resulted in flea mortality of 83.5, 73.3 and 42.5%, respectively. The efficacy of Clutia pulchella compared well with that of Karbadust which had a mean mortality of 97.5%. Paraffin, used engine oil, and Jeyes fluid (19.2%) caused higher flea mortality of more than 82%. In the in vivo study 60 free-range chickens were artificially infested with fleas and test materials were topically applied on infested sites. Test materials exhibited varying flea load reduction efficacy. Used engine oil and Jeyes fluid at 76.8% concentration had a reduction efficacy of 100 and 96% after 3 days post application of test materials. These were not significantly different to that of the positive control Kabadust (carbaryl 5%). The plants C. pulchella and C aurea at 100% concentration had an efficacy of 92 and 77%, respectively. The commonly used remedies by resource-limited farmers to control fleas vary in efficacy. Some of the materials are as effective as the commercial insecticides hence they have a potential to be exploited as insecticides. Further investigations on plant compounds with insecticidal properties and their toxicity, need to be conducted before the plants are recommended for use.

Thesis (PhD(Agric))--Stellenbosch University, 2012.<br>The sugarcane borer, Eldana saccharina Walker (Lepidoptera: Pyralidae) is the most limiting factor in the South African sugar industry with losses to this insect pest estimated to be at least ZAR60 million per annum. Because of its cryptic nature as well as the fact that E. saccharina is both indigenous to Africa and occurs on several host plants, attempts to control or eradicate it using several available methods have not been very successful. However, the sterile insect technique (SIT) is one of the newer control methods that can be incorporated into an area-wide integrated pest management (AW-IPM) programme to achieve better control or eradication. The implementation of the SIT program needs to go through a series of well-researched phases in order to be successful. In the first of this multi-phase project, it was determined that E. saccharina is susceptible to ionizing radiation, and is thus a suitable candidate for the SIT development against it and that a sub-sterilizing dose of 200 Gy is sufficient to induce F1(inherited) sterility in male and complete sterility in female moths respectively. The results presented here are discussed in the context of further development of the SIT as an addition to the arsenal of tactics in an AW-IPM programme against E. saccharina. Based on these initial findings, the study examined the lek and mating behavior of male moths subjected to three radiation doses (150, 200, 250 Gy) against normal non-irradiated/fertile moths. Both mass-rearing and irradiation of E. saccharina led to a quantitative departure of male mating behavior away from that exhibited by their wild counterparts. However, treated males are still able to form leks and mate with wild females. Male E. saccharina irradiated at all three doses tested were found to be as active and competitive as wild males, but in some of the traits measured, performance diminished significantly with an increase in the radiation dosage. In general, the performance of moths treated at 200 Gy did not differ significantly from that of moths treated at 150 Gy and therefore the former dose is ideal for SIT development since it results in a lower residual F1 fertility than the latter. The level of mating competitiveness and compatibility was assessed under both laboratory and semi-field conditions in pairwise comparisons consisting of laboratory reared vs. wild (L-W), 200 Gy irradiated vs. wild (S-W) and laboratory reared vs. irradiated moths (L-S). Based on the results from the more robust field cage assays, the mating indices generated indicated that the mass-reared E. saccharina strain produced in South Africa has not yet evolved sexual behaviours suggestive of incipient pre-mating isolation barriers with local wild strains. Wild moths did not discriminate against either the partially sterile or laboratory reared moths and most importantly, the irradiated males mated significantly more than their wild counterparts regardless of the type of female. The irradiated insects could therefore achieve the purpose for which they are intended upon release into the field. Third, the critical thermal limits (CTLs) to activity at high and low temperatures (i.e. critical thermal maxima “CTmax” and minima “CTmin”) of different E. saccharina strains/treatments were investigated under standard experimental conditions. The effect of laboratory rearing and increasing radiation dosage on thermal tolerance of the adult stage of E. saccharina was explored. There were highly significant differences between the laboratory-reared and wild strain and also between non-irradiated and irradiated strains in both CTmax and CTmin. Laboratory reared E. saccharina moths were more heat tolerant compared to wild moths for both genders while in the case of CTmin, the reverse was true. Irradiation had a negative effect on both CTmax and CTmin. Moths treated at the lowest radiation dose were more cold and heat tolerant than those treated at higher dosages thereby reinforcing the importance of lower dosages rather than those that induce full sterility against E. saccharina. In general, gender effects on the CTLs were non-significant. Pilot sterile male releases in shade house trials to measure the impact of sustained releases of partially sterile adult males at an over-flooding moth ratio of 10T: 1U (treated to untreated),were conducted to measure their efficacy to stop E. saccharina incursions and suppress populations prior to testing in pilot studies under true season-long and area wide conditions. Results from the current study demonstrated that releasing partially irradiated (200 Gy) adult male moths at the afore mentioned release rate significantly reduced sugarcane stalk damage as well as lowered the number of fertile progeny from F1to succeeding generations in a stable E. saccharina population initiated in a cage house. There were more damaged internodes per stalk in the control than in the sugarcane receiving regular releases of partially sterile male moths. Overall, there were significantly more undamaged stalks in the treated sugarcane than the untreated control. Furthermore, there were significantly more larvae per stalk retrieved from the control compared to the treated sugarcane suggesting that the sustained release of steriles was efficacious in reducing emergence of fertile larvae in the succeeding generations. The results of this study indicate that there is considerable scope for the SIT against E. saccharina.

Even as the current linear value chains (LVC) of organic waste and animal feed hold the potential to become circular, these practices continue to pose major environmental risks such as deforestation and overfishing. Therefore, a novel circular value chain (CVC) is proposed, connecting the organic waste stream with animal feed production by the use of insect-based organic waste conversion technology. The Black Soldier Fly (BSF) is chosen as the insect-based conversion technology since it has nutritional properties, which serves both waste treatment and animal feed material production purposes. Although there are already initiatives and collaborations in the Swedish context, the transition has not yet been successful. The study aims to identify and propose required solutions for the value chain transition. By using the transitional study tools of Technological Innovation System (TIS) and Multi Level Perspective (MLP) alongside sustainable value chain transition studies, it is found that technological and information-related adjustments are required to further enable the transition. Technological adjustments are studied from the perspective of Ragn-Sells AB as a potential insect- based organic waste conversion actor. Scenarios to see economical sustainability were designed based on the quantity fluctuation of waste as material input (3,000 tons per year and 15,000 tons per year), possibility of automated operation which affects both investment and operating costs of the facility, and procurement of small BSF larvae (off-site and in-site breeding). From the different scenarios designed, it is found that the scenario with the capacity of 15,000 tons per year, higher investment due to automation, and on-site breeding is the most preferable for the case. To answer information- related needs, an Informational Flow Framework (IFF) is proposed. The IFF consists of “Value Chain Stakeholders”, “CVC Relevant Regulations”, “Information Data Pool”, and “Information Flow”. The framework’s main function is to identify the type of material information required to be distributed in the system and the stakeholders whom require and/or provide various information, with the main goal of increasing the trust among the stakeholders related to material information.<br>Trots att den nuvarande linjära värdekedjan (Linear Value Chain) för organiskt avfall och djurfoder har potentialen för en cirkulär ekonomi, så utgör den nuvarande praxisen fortfarande stora risker såsom avskogning samt överfiske. Därför föreslås en ny cirkulär värdekedja (Circular Value Chain), som förbinder den organiska avfallsströmmen med djurfoderproduktion med användning av insektbaserad omvandlingsteknologi för organiskt avfall. Svart soldat fluga (Black Soldier Fly/BSF) utses som den insektsbaserade omvandlingsteknologin eftersom den har näringsegenskaper som bistår både avfallsbehandling och djurfoderproduktionsändamål. Trots att det redan finns initiativ och samarbeten i det svenska sammanhanget har övergången ännu inte lyckats. Studien syftar till att identifiera och föreslå nödvändiga lösningar för den cirkuläravärdekedjan. Genom att använda övergångsstudieverktygen av Teknologiskt Innovations System (TIS) samt Multi Level Perspective (MLP) och diverse värdekedjeövergångsstudier, konstateras det att tekniska och informationsrelaterade justeringarkrävs för att ytterligare möjliggöra övergången från en linjär till en cirkulär värdekedja. Teknologiska anpassningar studeras ur Ragn-Sells ABs perspektiv som en potentiell aktör för omvandling av organiskt avfall. Scenarier för att undersöka ekonomisk hållbarhet utformades baserat påfluktuering av mängden avfall som materialinmatning (3,000 ton per år och 15, 000 ton per år), möjlighet till automatiserad drift som påverkar både CAPEX &amp; OPEX i anläggningen (hög CAPEX och låg CAPEX), och upphandling av små BSF-larver (avel utanför anläggningen). Från de olika utformade scenarierna konstaterades att scenariot med en kapacitet på 15,000 ton per år, hög CAPEX och avel på plats är det mest fördelaktiga för Ragn Sells AB. För att besvara informationsrelaterad justering föreslås en informationsflödesram (IFF). IFF består av ”Value Chain Interessholders”, “CVC Relevant Regulations”, “Information Data Pool” och “Information Flow”. Ramens huvudfunktion är att identifiera vilken typ av materialinformation som krävs för att distribueras i systemet och den aktör som kräver och/eller tillhandahåller informationen, med det huvudsakliga målet att öka förtroendet bland aktörerna relaterade till materiell information.

Etude du role des termites dans 3 sites: une foret secondaire et 2 plantations. Les populations de termites sont plus importantes en foret. Le defrichement provoque une chute des effectifs qui se reconstituent ensuite rapidement. En saison seche, les termites s'enfoncent dans le sol. La recolte de bois mort par les termites varie selon la saison. Les termites sont inoffensifs pour les arbres eb bon etat. Par contre, l'action des termites constitue un reel danger pour les jeunes arbres, surtout chez les sujets fletris. Il existe une correlation positive entre le degre de fletrissement et le taux d'attaque. C'est apres 2 ans que les termites attaquent et fragmentent la litiere d'eucalyptus

O incremento aos programas de bioenergia em nosso país, aponta para uma provável duplicação da área plantada de cana-de-açúcar, num futuro bastante próximo. Neste contexto, a sustentabilidade da cultura deve ser preservada, evitando-se que sejam colocados em risco os avanços obtidos nas últimas cinco décadas no Controle Biológico de suas pragas. Para tanto, são necessárias pesquisas que atendam às necessidade das diversas etapas de um programa de Controlo Biológico. No presente estudo, avaliou-se o uso de temperaturas diferentes para criar cada fase do desenvolvimento de Diatraea saccharalis (Fabricius, 1794), com o objetivo de fornecer informações importantes para sua criação massal. Avaliou-se também, o raio de ação de uma armadilha contendo fêmeas virgens, a dinâmica populacional de D. saccharalis e o seu desenvolvimento em plantas de cana-de-açúcar, visando desenvolver um modelo de previsão da praga, com vistas ao seu controle biológico pelos parasitoides T. galloi e C. flavipes. As combinações de temperaturas 28°C-25°C-25°C, 28°C-28°C-28°C, 30°C-25°C-25°C e 30°C-22°C- 22°C para criar lagartas, pupas e adultos, respectivamente, destacaram-se das demais por promover rápido desenvolvimento aliado a altas taxas reprodutivas e podem assim, serem utilizadas para a criação massal de Diatraea saccharalis (Fabricius, 1794) e de seu parasitoide Cotesia flavipes (Cameron, 1891). O aumento de densidade de criação de 1 lagarta por tubo para 250 lagartas por frasco, não afetou o desenvolvimento e reprodução de D. saccharalis. Foi possível prever o momento de liberação de C. flavipes em cana-de-açúcar com base em modelos de exigências térmicas, assim como, orientar as liberações de T. galloi ao definir o período de ocorrência dos ovos de D. saccharalis. Os parâmetros climáticos determinaram uma faixa térmica de atuação para as armadilhas contendo fêmeas virgens (temperatura média acima de 24°C), faixa na qual foram observadas altas correlações entre a captura de machos e amostragem de lagartas, realizada 21 dias após a captura dos machos de D. saccharalis. De acordo com a dinâmica populacional de D. saccharalis, foram identificadas quatro gerações ao longo do ciclo da cultura. Para a utilização do parasitoide de ovos T. galloi deve-se usar uma armadilha contendo 4 fêmeas virgens de D. saccharalis para amostrar 12,5 ha, área determinada em função do raio de ação de 200 metros.<br>The increase of bioenergy programs in our country indicates a probable duplication of the planted area with sugar cane in a near future. In this context, the sustainability of the culture must be preserved, avoiding the risk of loose the progress achieved in the last five decades in the Biological Control of its pests. For this, it is necessary researches that attend the needs of the various steps of a biological control program. In this study, was evaluated the use of different temperatures to rear each phase of the development of Diatrea saccharalis (Fabricius, 1794), aimed to provide important informations for its mass rearing. It was also evaluated the radius of action of a trap containing virgin females, the population dynamics of D. saccharalis and its development in sugar cane, aimed the development of a prediction model of the occurence of D. saccharalis in sugar cane, suporting its biological control by the parasitoids T. galloi and C. flavipes. The temperatures combination 28°C-25°C-25°C, 28°C-28°C-28°C, 30°C-25°C-25°C, and 30°C-22°C- 22°C used to rear caterpillar, pupae and adults stood out from the others by promoting fast development combined with high reproductives rates and can be used for mass rearing of Diatraea saccharalis (Fabricius, 1794) and its parasitoids Cotesia flavipes (Cameron, 1891). The rearing of caterpillars individually or in groups of 250 did not interfere in the development and reproduction of D. saccharalis. It was possible to predict the release time of C. flavipes in sugar cane based in thermal requirements models and advise the releases of T. galloi deffining the period of occurrence of D. saccharalis eggs. The climatic parameters determined a temperature range of action for the pheromone traps with the virgin females (average temperatures above 24°C), range at which high correlations were observed between the males capture and caterpillar sampling performed 21 days after the capture of the D. saccharalis males. According to the population dynamics of D. saccharalis, four generations have been identified during the crop cycle. For the use of the egg parasitoid T. galloi, it should be used a trap containing four virgin femeales of D. saccharalis to sample 12.5 ha, area determined by the action radius of 200 meters.