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Dissertations / Theses on the topic 'Insect species'
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1
Loder, Natasha. "Insect species-body size distributions." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284385.
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Srivastava, Diane Sheila. "Ecological evolutionary limits of local species richness." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244120.
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Ringel, Michael Stanley. "Ecological and evolutionary dynamics of interacting insect species." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362514.
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Morath, Simon. "Effects of tree species diversity on insect herbivory." Thesis, Royal Holloway, University of London, 2013. http://repository.royalholloway.ac.uk/items/916c671f-79af-41eb-99b1-df69faa84961/1/.
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It is generally believed that tree species growing in mixed forest stands are less susceptible to insect herbivore damage than if grown in monocultures, but previous studies have been largely observational and focussed mainly on tree species richness effects. In this thesis, I examined effects of three components of forest diversity (tree species richness, intraspecific genotypic diversity and functional diversity) on insect herbivores using three long-term forest diversity experiments in Finland and Germany. I have also explored the sources of variation in and the mechanisms behind the effects of tree diversity on insect herbivores. I found that all three components of forest diversity significantly influenced insect herbivore abundance and damage. Tree species richness effects depended on the insect herbivore feeding guild, but also changed within season and between years. As a result, silver birch (Betula pendula) experienced both associational resistance (reduced damage in mixed stands) and associational susceptibility (higher damage in mixed stands) to different insect herbivores and in some instances this altered temporally. In contrast, tree species richness effects on insect herbivory were spatially consistent and not mediated by tree size (physical apparency), physical properties of leaves or natural enemies. Interestingly, tree species richness and genotypic diversity had opposite effects on leaf miners; leaf miner abundance and species richness were lower in species-rich stands, but higher in mixtures containing several genotypes of silver birch. To test the effects of tree functional diversity, I created a functional diversity index based on constitutive emissions of monoterpenes and isoprene by different tree species and showed that tree species which emitted low levels of volatiles experienced associational resistance in stands with high diversity of volatile emissions. This suggests that increasing chemical complexity in mixed stands may interfere with host finding ability of herbivores.
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Fazakerley, Claire. "Molecular coevolution between developmental genes in insect species." Thesis, University of Leicester, 1996. http://hdl.handle.net/2381/34410.
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Changes in the regulatory sequences of the genes involved in development are thought to be important in the evolution of morphology. However, molecular coevolution between functionally interacting genetic elements allows sequence divergence to be tolerated whilst the functional interaction is maintained. Molecular coevolution can lead to species-specificity in the sequence basis underlying molecular interactions. The concentration-dependent activation of hunchback (hb) expression in the anterior half of the Drosophila melanogaster embryo by the gradient of bicoid (bcd) protein represents a primary step in the elaboration of pattern along the anterior- posterior axis, and this interaction is conserved in the housefly, Musca domestica. In order to investigate the possibility that the molecular basis of this interaction may have coevolved, the bed and hb genes have been partially sequenced from M. domestica and compared to those of D. melanogaster. Analysis of the putative M. domestica hb regulatory region identified three candidate bed binding sites, with a consensus sequence of TTTAATCC, rather than the TCTAATCC of D. melanogaster. Comparison of the bed sequences revealed 5 changes within the 60 amino acids of the homedomain. Hence, it is possible that M. domestica bcd may have a subtly altered binding specificity, pointing towards the possibility that the coordinated changes in the binding site sequences have elicited compensatory changes in the M. domestica bed homeodomain. Preliminary analyses have been made of the functional significances of the observed differences. Although the functional significance of the observed differences in the bed and hb genes is not fully understood, the possibility remains that the molecular nature of the interaction between bed and hb has diverged between M. domestica and D. melanogaster.
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Byington, Sarah. "Antibiotic resistant enterococci in laboratory reared stored-product insect species and their diets." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32906.
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Master of ScienceDepartment of Grain Science and Industry
Bhadriraju Subramanyam
Hulya Dogan
Stored-product insects and stored products from feed mills and swine farms contain antibiotic and potentially virulent Enterococcus faecalis, Enterococcus faecium, Enterococcus casseliflavus, Enterococcus gallinarum, and Enterococcus hirae. Stored-product insects can serve as potential vectors of these enterococci which possess antibiotic resistance genes that can be spread by horizontal transfer to more serious human pathogens. In the present study, the species and concentration of enterococci from adults and larvae of key stored-product insects and insect diets and their antibiotic resistance profile were characterized. Adults of five species out of the 15 stored-product insects were tested positive for enterococci, and these included Callosobruchus maculatus (F.), Sitophilus granarius (L.), Stegobium paniceum (L.), Lasioderma serricorne (F.), and Sitophilus zeamais Motschulsky. Three enterococcal species (E. casseliflavus, E. faecalis, and E. faecium) were found in 53 to 97% of the 30 adults screened for each insect species, and the enterococcal concentrations ranged from 1.4 x 10³ to 3.1 x 10⁶ CFU/adult. About 10 to 100% of the mature larvae of the respective five insect species had these three enterococcal species with concentrations ranging from 0.3 x 10¹ to 1.4 x 10⁵ CFU/larvae. Only three of the eight insect diets screened had the same three enterococci species in addition to E. gallinarum and E. hirae at concentrations of 0.2 x 10¹ to 5.9 x 10³ CFU/g. The greatest enterococcal concentration was found in C. maculatus adults but not in their larvae or diet (cowpeas). In C. maculatus during a nine-day period after adult eclosion, the enterococcal concentrations increased exponentially from 0.6 x 10¹ to a maximum of 4.1 x 10⁷ CFU/adult. Enterococci were detected in the fecal material of C. maculatus during a four-day period with a maximum concentration of 3.3 x 10³ CFU/adult on the fourth day. A total of 298 enterococcal isolates from adults, larvae, and diets were represented by E. faecalis (51.7% of the total), E. faecium (19.1%), E. casseliflavus (18.8%), E. gallinarum (5.7%), and E. hirae (4.7%). Enterococci were phenotypically resistant to quinupristin (51.3% of the total), erythromycin (38.9%), tetracycline (30.1%), enrofloxacin (29.2%), doxycycline (11.5%), and tigecycline (2.7%). All isolates were susceptible to ampicillin and vancomycin.
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Malek, Robert Nehme. "Novel Monitoring and Biological Control of Invasive Insect Pests." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/257781.
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Invasive species are alien to the ecosystem under consideration and cause economic or environmental damage or harm to human health. Two alien insects that fit this description are the brown marmorated stink bug, Halyomorpha halys and the spotted lanternfly, Lycorma delicatula. Both invaders are polyphagous pests that feed on a myriad of plant species and inflict severe crop losses. As sustainable control methods depend on the accurate monitoring of species’ invasion and involve the use of natural enemies, we addressed these two facets by exploring novel monitoring techniques and deciphering host-parasitoid interactions for improved integrated pest management. Thus, we adopted ‘BugMap’, a citizen science initiative that enables students, farmers and everyday citizens to report sightings of H. halys from Italy, with emphasis on Trentino-Alto Adige. Aside from fostering citizen participation in scientific endeavors and the enhanced literacy that ensues, BugMap helped uncover the invasion dynamics of H. halys and forecast its potential distribution in Trentino, all while coordinating technical monitoring and informing management strategies. The most promising agent currently under study for the classical biological control of H. halys is the Asian egg parasitoid Trissolcus japonicus. To assess the wasp’s potential non-target impacts, we investigated its foraging behavior in response to chemical traces ‘footprints’ deposited by its main host H. halys and by a suboptimal predatory species, the spined soldier bug, Podisus maculiventris. Wasps exhibited a ‘motivated searching’ when in contact with footprints originating from both species. However, T. japonicus arrestment was significantly stronger in response to H. halys footprints, compared with P. maculiventris, implying the presence of underlying chemical cues that shape its natural preferences. A series of GC-MS chemical analyses revealed that n-tridecane and (E)-2-decenal were more abundant in H. halys footprints and are probably the key components utilized by the wasp for short range host location. The function of the aforementioned compounds was studied, n-tridecane acted as an arrestant, prolonging T. japonicus residence time, whereas (E)-2-decenal fulfilled its presumed defensive role and repelled the wasp. These results shed new light on the chemical ecology of T. japonicus and help expand the understanding of parasitoid foraging and its implications for classical biological control. Moving to the other invader L. delicatula, an egg parasitoid Anastatus orientalis was reported attacking it at high rates in its native range in Eastern Asia and may play a key role in reducing its populations there. A series of bioassays revealed that wasps responded to footprints deposited by L. delicatula gravid females by initiating a strong searching behavior. Moreover, A. orientalis preferred to oviposit in egg masses with intact oothecae, suggesting that the host’s egg covering functions as a trigger for A. orientalis probing and oviposition. Thus, A. orientalis not only overcomes, but also reverses an important line of host structural defense for its own fitness gains. This dissertation discusses the benefits of combining citizen science with traditional monitoring, and the usefulness of decoding host-parasitoid interactions to design more efficacious management strategies of invasive insect pests.
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Gavloski, John E. "Insect-specific responses of Brassica napus and Sinapis alba to herbivory by several species of insects." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ31983.pdf.
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Merkley, Steven S. "An Invasive Species Reduces Aquatic Insect Flux to Terrestrial Food Webs." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2806.
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Although it is well documented how introduced species can negatively affect native species, we only poorly understand how they may alter ecosystem functions. We investigated how an invasive fish affected the flux of aquatic insects to terrestrial food webs using mesocosms in a desert spring ecosystem. We compared aquatic insect emergence between alternative community states with monocultures and polycultures of two native species of fish, least chub (Iotichthys phlegethontis) and Utah chub (Gila atraria) plus, introduced western mosquitofish (Gambusia affinis). We tested three hypotheses: (1) aquatic insect biomass will be greater than terrestrial insect biomass and thus, constitute a vital source of energy for terrestrial consumers (2) invasive mosquitofish will negatively impact the biomass of emerging aquatic insects, and (3) terrestrial consumers will negatively respond to decreased emerging aquatic insect biomass. Aquatic insects represented 79% of the flying insect community, and treatments with mosquitofish significantly reduced emergent aquatic insect biomass by 60% relative to the control without mosquitofish. Behavioral traits of invasive species are important, because mosquitofish most heavily affected insects that emerged during the day. Also, spiders that build horizontal webs were negatively correlated with decreasing aquatic insect biomass. Invasive mosquitofish can achieve very dense populations because of their high intrinsic rate of population increase, which can significantly disrupt the flow of energy between aquatic and terrestrial ecosystems, thereby reducing the energy available for terrestrial consumers.
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Mesfin, T. "Biological and feeding studies of Cicadulina species (Homoptera : Cicadellidae)." Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380309.
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Spencer, Andrew. "Short-term task allocation in small social insect groups." Thesis, University of Bath, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341102.
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Mercader, Rodrigo J. "Species ranges, host selection, and hybridization how increased hybridization is leading to host use divergence in a polyphagous sibling species pair /." Diss., Connect to online resource - MSU authorized users, 2008.
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Thesis (Ph.D.)--Michigan State University. Dept. of Entomology and Program in Ecology, Evolutionary Biology, and Behavior, 2008.Title from PDF t.p. (viewed on July 17, 2009) Includes bibliographical references (p. 115-126). Also issued in print.
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Eiríksson, Thorleifur. "Female response and male singing strategies in two orthopteran species." Edsbruk : Akademitryck, 1992. http://catalog.hathitrust.org/api/volumes/oclc/27738733.html.
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Parker, Denisha M. "Drivers of Predatory Insect Distribution in Urban Greenspaces." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1619126809030714.
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Torres, Kieron Marie. "Acquisition and Retention of Bacterial Spores (Bacillus Atrophaeus) by Eight Insect Species." VCU Scholars Compass, 2006. http://hdl.handle.net/10156/1988.
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Olckers, Terence. "Biological studies of insect herbivores associated with some species of Solanum L." Thesis, Rhodes University, 1989. http://hdl.handle.net/10962/d1002043.
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Solanum mauritianum Scop. (bugweed), a serious exotic weed in South Africa, supports a depauperate herbivore fauna relative to indigenous Solanum species. These comprise mainly polyphagous, and some oligophagous, species. The greater diversity of insect herbivores on Solanum hermannii Dun., relative to other indigenous Solanum species in the eastern Cape, suggests that the plant is indigenous and not exotic as has been suggested. Five oligophagous species seasonally caused a high incidence of damage to S.hermannii and other indigenous Solanum species in the eastern Cape, during the study period. Galls of the flowers, stems and leaves of some indigenous Solanum plants are described and biological data on the gall-formers and their natural enemies presented. The tortoise beetle, (Chrysomelidae), defoliates a Conchyloctenia tigrina wide range of indigenous Olivo Solanum species. The exotic S.mauritianum and S.elaeagnifolium Cav. were unfavourable for growth and survival. S.hermannii proved the most favourable of the indigenous hosts tested, for growth and survival, providing further evidence that it is indigenous. Extensive studies on different field populations of the beetle revealed no evidence of host adaptation (host races). All populations tested displayed greater fitness when reared on S.hermannii. South African Solanum faunas are characterized by a scarcity of endophagous and monophagous herbivores, vacant feeding niches and low numbers of species relative to other plant taxa. This may suggest evolutionary immaturity of the insect-plant associations, although comparative studies of solanums from other parts of the world are needed for confirmation. Alternatively, these characteristics may simply be a feature of the genus Solanum in general. The depauperate herbivore fauna of S.mauritianum reflects a lack of local herbivores suitably preadapted to overcome its defences. This appears to be accentuated by absence of any close relatives of bugweed in South Africa. The greater diversity of herbivores in its native South America suggests that biological control may be a potentially useful means of control for bugweed. The potential for biological control is, however, threatened by the susceptability of the cultivated eggplant (Solanum melongena L.) to attack by Solanum-feeding insects. Possible solutions to this problem are discussed
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Al, Rustamani Hind Abdul Wahed Hassen. "Characterisation of two constitutively expressed proteins in two trypanosomatid species." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321901.
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Clapp, Justin Peter. "Selective enrichment of genomic DNA data for the isolation of species-specific probes in insects." Thesis, University of Hertfordshire, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296538.
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Steffan, Shawn Alan. "Biodiversity and fear ecology the cascading effects of species richness and nontrophic interactions /." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Dissertations/Spring2009/s_steffan_041709.pdf.
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Holt, Rohan H. F. "Susceptibility of different insect species to infection by Hymenolepis diminuta and Moniliformis moniliformis." Thesis, University of Glasgow, 1989. http://theses.gla.ac.uk/2439/.
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Chapter 2 Natural concurrent infections of rats with H. diminuta and M. moniliformis may increase the chances of individual insects being infected by both parasites simultaneously. Although previous work has shown H. diminuta and M. moniliformis can co-exist in the small intestine of the rat, it was considered important to determine the length of time the two species would be simultaneously patent. This time period would occur during maximum rate of egg production by both parasite species, determined from numbers of eggs found the rat's faeces. It was concluded that although eggs of both species were found in the faeces for proximity 11 weeks post-infection, the chances of an insect acquiring an infection would be highest at the time of peak egg production. This was approximately 6 weeks in the mid-patent period of M. moniliformis. Chapter 3 The initial process leading to an infection of the intermediate host by H. diminuta and M. moniliformis were examined; i.e. egg ingestion, hatching, passage along the insect gut and penetration of the midgut wall. Adaptations by the larvae of both species of parasite to infect the intermediate host were shown to influence host-specificity. H. diminuta and M. moniliformis hatched in the guts of a wide variety of insect species, but only M. moniliformis acanthors penetrated the gut wall of P. americana. H. diminuta oncospheres only penetrated the gut walls of the locusts, Schistocerca gregaria and their natural hosts, the flour beetles Tribolium confusum and Tenebrio molitor. Transit time for food material passing along the gut was found to be important in the synchronisation of parasite hatching with arrival at the site of gut penetration. P. americana holds food items and parasites in the foregut (crop) until partially digested before allowing them into the midgut. Thus any H. diminuta oncospheres stimulated to hatch by the insect's mouthparts only progressed as far as the crop until initial digestion was completed; the time taken for crop contents to be passed in to the midgut tended to exceed the time larvae remained active and capable of gut penetration. In contrast, M. moniliformis acanthors hatch over a longer time period and therefore enter the midgut in a state capable of gut penetration. The abilities of the two species of parasite to tunnel through the midguts of different insect species was compared in vitro using a qualitative assay technique. H. diminuta oncospheres were unable to penetrate the tissues of P. americana midgut. Chapter 4 Eggs from both species of parasite were fed simultaneously to insects. It was initially proposed that oral infections of cockroaches with M.moniliformis might facilitate penetration of the cockroach gut by H. diminuta oncospheres, if the gut tissues were sufficiently disrupted by the former parasite. However, only locusts could be simultaneously infected with both species orally, infected, and viable H. diminuta oncospheres fed to cockroaches were found to adversely affect the success of a simultaneously offered dose of M. moniliformis eggs (acanthors). A hypothesis was put forward to explain this result; that H. diminuta oncospheres perturbed the midgut tissues in their unsuccessful attempt to burrow through the gut wall, thus initiating a wound-healing response by the hosts immune system. This resulted in gut-penetrant M. moniliformis larvae being killed by a melanotic encapsulation reaction. Unfortunately, light and electron microscopy has revealed little evidence of such a wounding in the gut which might have initiated such an immune response. Chapter 5 H. diminuta oncospheres were injected directly into the cockroach haemocoele, as it has been previously shown that a small number of parasites survive. By repeatedly passaging the few surviving cysticercoids from each infection through the rat/cockroach system it was hoped to raise a cockroach-infective strain of H. diminuta. However, their infectivity to cockroaches did not increase in successive generations; several explanations for the possible failure of this selection programme have been put forward. Intrahaemocoelic injections of pre-hatched H. diminuta oncospheres or M. moniliformis acanthellae into the host made it possible to by-pass the gut and thus investigate concurrent haemocoelic infections of cockroaches with both species of parasite. When H. diminuta was injected into M. moniliformis-infected cockroaches, prevalence and intensity of the former were significantly elevated compared to naive controls, indicating that a putative immunosuppressive action from M. moniliformis facilitated H. diminuta development. In some instances, H. diminuta was found to have burrowed through the envelope surrounding M. moniliformis and continued normal development within, unmolested by the host's haemocytes. This was considered as further evidence for the protective nature of the acanthocephalan envelope. Chapter 6 In Chapter 6, assays for aspects of haemocyte behaviour was performed on insects (in particular, P. americana) experimentally infected with either M. moniliformis or H. diminuta. It was found that the phenomenon seen in Chapter 4, whereby H. diminuta adversely affected the success of M. moniliformis when fed simultaneously to cockroaches, appears to be a direct consequence of the stimulatory effect of H. diminuta on the immune system. Conversely, the developing larvae of M. moniliformis were shown to depress haemocytic activity; possibly explaining why elevated numbers of injected H. diminuta survive in M. moniliformis-infected cockroaches. To investigate the affects of immune stimulation on the survival of parasites, locusts were injected with Zymosan, a derivative of yeast cell walls containing 1,3-glucans. H. diminuta oncospheres, injected into Zymosan-stimulated locusts appeared to be partially encapsulated, resulting in a temporary arrest in their development when compared to controls. An assay was devised to observe the encapsulation of materials in vitro by the haemocytes of P. americana. This method was used to show differences in the haemocytic encapsulation reaction to the different larval stages of M. moniliformis and H. diminuta. Both the gut-penetrant stages of each parasite (i.e. oncospheres and acanthors) were encapsulated, whereas the haemocoelic stages (i.e. cysticercoids and acanthellae to cystacanths) remained free of haemocytes. Chapter 7 Finally, in Chapter 7, a model for the alternative pathways leading to success or failure of parasitism by H. diminuta and M. moniliformis in the insect host has been discussed. The results presented here contribute to the fuller understanding of how immune stimulation and immunosuppression affect the survival of helminth parasites, particularly in the cockroach host. These two phenomena have also been shown to be effected by the parasites themselves.
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Scarr, Andrew. "The toxicokinetics of imidacloprid in a target and non-target insect pest species." Thesis, University of Portsmouth, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310468.
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Whu, Alyssa. "Boundary Dynamics Across Habitat Edges: Effects on Beneficial Insect Species Abundance and Richness." Miami University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=miami1346122386.
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Ruiz, Carbayo Helena. "The role of landscape and species attributes in insect community assembly, population genetics and plant-insect interactions in expanding Quercus ilex forests." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/650282.
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Los mecanismos responsables de la colonización y coexistencia de las especies en los hábitats,
es uno de los mayores rompecabezas en ecología de comunidades. Varias teorías, entre ellas la
teoría de nicho, neutral y de coexistencia, han intentado explicar la biodiversidad observada en
los ecosistemas naturales como el resultado de procesos determinísticos, neutrales o una
combinación de ambos, respectivamente. Esta biodiversidad se estructurará primero en
comunidades y más tarde en interacciones bióticas que únicamente pueden ser entendidas
desde la doble perspectiva de la ecología del paisaje y las dinámicas de
metapoblaciones/metacomunidades. La pérdida de comunidades e interacciones bióticas ha
sido extensamente estudiada en hábitats en proceso de regresión y fragmentación, sin
embargo, no ha sido ese el caso del ensamblaje de comunidades e interacciones en hábitats
en expansión. En el actual contexto de cambio global, la transformación del suelo ha dado
lugar a la pérdida de y fragmentación de hábitat en diferentes ecosistemas, sin embargo, la
recuperación de hábitats naturales también se ha observado. Particularmente en Europa, el
abandono de los cultivos ya causado la aparición de mosaicos forestales. Especialmente en
estos hábitats parcheados, los procesos neutrales modulados por las características
espaciotemporales del paisaje así como la capacidad de dispersión de los organismos podría
estar jugando un papel crucial en el ensamblaje de las comunidades de las interacciones
bióticas. Sin embargo, otros procesos determinísticos también podrían estar actuando a otras
escalas espaciales El objeto de esta tesis es la de ahondar en el conocimiento de los factores
que dirigen el ensamblaje de las comunidades y las interacciones bióticas, considerando como
sistema de estudio la interacción planta-insecto establecida entre Quercus ilex y su comunidad
de insectos herbívoros (folívoros y granívoros). Los principales objetivos fueron: a) cuantificar
los efectos de las características individuales de Q. ilex como la edad, el tamaño de copa, la
conectividad, la genética y la localización, sobre el ensamblaje de los herbívoros y la
herbivoría, b) explorar los efectos de la edad y la conectividad del hábitat en combinación con
la capacidad de dispersión de los herbívoros, en el ensamblaje de la comunidad de granívoros
y la granivoría a diferentes escalas espaciales, y finalmente, c) elucidad si existen evidencias
genéticas dentro de la comunidad de depredadores de semillas de los efectos de las
diferencias en capacidad de dispersión en el espacio y el tiempo dentro del gremio de
granívoros. El Capítulo 2 muestra una compleja interacción entre la edad, tamaño de copa y
conectividad de los árboles situados en dehesas emergentes, con comunidades de
lepidópteros más abundantes, ricas y diversas en los árboles más viejos, grandes y mejor
conectados, mientras que la composición (alpha y beta) depende exclusivamente de la
distancia entre árboles. El Capítulo 3 muestra en efecto directo de la genética del árbol sobre
el daño por herbivoría, como también un efecto borde que beneficia a los insectos en el
interior del parche, mientras que un efecto interactivo de la edad y la conectividad de la
encina, provoca un fenómeno de asociación por resistencia entre las encinas que ya han
alcanzado el estatus de árbol. Encontramos más evidencias del impacto de las características
individuales del árbol sobre la herbivoría en el Capítulo 4, donde la depredación de bellotas es
regulada por el tamaño de la bellota y la conectividad del árbol, mientras que dicha herbivoría
no cambia entre hábitats o paisajes a la escala local y regional, debido a dinámicas
compensatorias entre las distintas especies del gremio de granívoros (diferentes gremios a
escala local pero un efecto nulo del paisaje sobre la depredación de bellotas a escala de
paisaje) Además de estos efectos en la composición, en el Capítulo 5 los resultados revelan
una estructura genética significativa y una baja variabilidad local sólo para la especie que peor
dispersa en el espacio, C. elephas, además de mostrar una restricción en el flujo genético entre
bosques maduros y bosques nuevos aislados, de acuerdo con el crédito de colonización
revelado en el Capítulo 4. A pesar del efecto fundador, C. elephas presenta poblaciones más
abundantes que su especie hermana C. glandium, lo que podría sugerir que otros factores
están favoreciendo su fitness.
En general, nuestros resultados aportan información detallada sobre los procesos ecológicos
que están mediando el ensamblaje Quercus ilex – herbívoro en nuevos bosques y a diferentes
escalas.The mechanisms driving species colonization and coexistence in habitats, is one of the main puzzles in community ecology. Several theories, including niche, neutral and coexistence theories, have tried to explain the biodiversity observed in natural ecosystems as the result of deterministic, neutral, or a combination of both processes, respectively. This biodiversity will assemble in communities and ultimately biotic interactions which can only be fully understood by the double perspective of landscape ecology and metapopulation/metacommunity dynamics. Loss of communities and biotic interactions has been thoroughly studied in the context of shrinking and fragmented habitats, but has been poorly explored in expanding habitats. In the current context of global change, land transformation has resulted in loss and fragmentation of habitat in many different ecosystems, however, recovery of natural habitats has also been observed. Particularly in Europe, cropland abandonment has led to the emergence of patchy forest mosaics. Especially in these patchy habitats, neutral processes modulated by spatiotemporal landscape attributes as well as dispersal ability of organisms could be playing a key role in the assembly of communities and biotic interactions. Nevertheless, deterministic processes might as well be shaping communities and interactions at other spatial scales. The aim of this thesis has been to deepen in the knowledge of factors driving community and interaction assembly, taking as study system the plant-insect interaction established between Quercus ilex and its community of herbivore (folivore and granivore) insects. The main objectives were: a) to quantify the effects of Q. ilex individual characteristics such as tree age, size, connectivity, genetics and location, on the assembly of herbivore community and herbivory, b) to explore the effects of habitat age and connectivity in combination with herbivore dispersal ability, on the assembly of granivore community and granivory at different spatial scales, and finally, c) to elucidate if there already exists a genetic signature within the seed-predator guild derived from the differences in dispersal in time and space among species. Chapter 2 shows a complex interplay of age, canopy size and connectivity of trees interspersed in an expanding savannah-like Q. ilex landscape, leading to more abundant, richer and more diverse Lepidoptera communities in older, larger and more connected trees, while alpha and beta diversity depending exclusively on the distance between canopies. Chapter 3 shows a direct effect of tree genetics on the leaf damage suffered by holm oaks, as well as an edge effect benefiting insects at the core of the patch, while an indirect effect of age and connectivity, resulting in associational resistance, is revealed among mature developmental 2 stages of holm oak. Additional support of tree characteristic impact on herbivory is found in Chapter 4, where seed-predation is regulated by acorn size and tree connectivity, while it does not change between habitats or landscapes at the local and regional scales, due to compensatory dynamics of the different species within the seed-predator guild (different seedpredator assemblages at the local scale but zero-sum landscape effects on seed-predation at the landscape scale). In addition to effects on the composition of the community, in Chapter 5 results revealed significant genetic structure and low genetic variability only for the poorest disperser, C. elephas, as well as restricted gene flow between old and new-isolated patches, in consonance with colonization credits found for this species in Chapter 4. In spite of the founder effects, consistent larger populations of C. elephas compared to the better disperser C. glandium suggest that other factors are favoring the fitness of the former species. Overall, our results provide a detailed insight on the processes that are mediating the Quercus ilex – herbivore assembly in expanding forests at different spatial scales.
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Stenbacka, Fredrik. "Response of saproxylic insect communities to forestry implications for conservation /." Umeå : Dept. of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200969.pdf.
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Walter, J. B. "Studies on the nodule formation as a cellular defence mechanism in some insect species." Thesis, Swansea University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639333.
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Roberts, David Mark. "Genome analysis of plant and insect pathogenic species of Verticillium using molecular DNA methodologies." Thesis, King's College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313053.
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Di, Vitantonio Cinzia <1984>. "Natural and Anthropogenic Factors Affecting the Life Cycle of Exotic and Native Insect Species." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7457/.
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My PhD thesis concerns natural and human factors that affect the life cycle of exotic and native insects. I compared, in laboratory, the longevity and the reproduction capacity of two coccinellid species, the exotic Harmonia axyridis (Pallas) and the native Adalia bipunctata (L.) after the exposure to the indigenous parasitoid Dinocampus coccinellae (Schrank) (Hymenoptera Braconidae). The aim was the evaluation of the effects induced by the parasitoid on the fitness of coccinellid females, with a particular stress on the Asian H. axyridis.
Moreover the study continued with the assessment of the parasitization effect of the native tachinid Exorista larvarum (L.) on the exotic box tree moth Cydalima perspectalis (Walker).
The aim was to check the possibility for Cydalima larvae to be accepted and/or successfully parasitized by the tachinid, with a complete development of the parasitoid through formation of puparia and emergence of adults.
Then, I studied the lethal and sublethal effects of two insecticides( the neonicotinoid Imidacloprid and the product of biological matrix, Spinetoram) on H. axyridis and A. bipunctata. The aim was to evaluate acute and long-term effects of the two insecticides on these predators in laboratory. These three parts are included in the GEISCA Program.
The last part is related to two laboratory experiments carried out at Wageningen University (NL). The study was inserted in the AMIGA Project, focused on the evaluation of the risk of GMO in the environment. In this study it was evaluated the impact of GM potato plants, resistant to the fungus Phytophthora infestans de Bary, towards the development time of the hymenopteran braconid Aphidius colemani Viereck. In the second experiment it was evaluated the development time of A. bipunctata fed on Myzus, that was reared on non-GM potato plants infected by P. infestans. The aim was to observe some effects on this coccinellidLa mia tesi di dottorato riguarda fattori naturali ed umani che influenzano il ciclo di vita delle specie di insetti esotici e nativi. Ho confrontato, in laboratorio, la longevità e la capacità di riproduzione di due specie coccinellid, l'esotico Harmonia axyridis (Pallas) e il nativo Adalia bipunctata (L.) dopo l'esposizione al parassitoide indigeno Dinocampus coccinellae (Schrank) (Hymenoptera Braconidae). L'obiettivo è stato quello di valutare gli effetti indotti dal parassitoide sulla idoneità delle femmine di coccinellidi, con particolare accento sulla H. axyridis asiatica. Inoltre lo studio è proseguito con la valutazione dell'effetto parassitizzazione del tachinide nativo Exorista larvarum (L.) sulla piralide del bosso Cydalima perspectalis (Walker). L'obiettivo era quello di verificare la possibilità per le larve di Cydalima di essere accettate e / o parassitizzate con successo dal tachinide, con un completo sviluppo del parassitoide tramite formazione di pupari e comparsa di individui adulti. Inoltre, ho studiato gli effetti letali e subletali di due insetticidi (il neonicotinoide imidacloprid e il prodotto di matrice biologica, Spinetoram) su H. axyridis e A. bipunctata. L'obiettivo era quello di valutare gli effetti acuti ea lungo termine dei due insetticidi su questi predatori in laboratorio. Queste tre parti sono incluse nel Programma GEISCA. L'ultima parte è legata a due esperimenti di laboratorio effettuati presso l'Università di Wageningen (NL). Lo studio è stato inserito nel progetto AMIGA, focalizzata sulla valutazione del rischio di OGM nell'ambiente. In questo studio è stato valutato l'impatto di piante di patate geneticamente modificate, resistenti al fungo Phytophthora infestans de Bary, verso i tempi di sviluppo dell’ imenottero braconide Aphidius colemani Viereck. In più è stato valutato il tempo di sviluppo di A. bipunctata alimentata con Myzus persicae Sulzer, allevato piante di patate non GM infettate da P. infestans. Lo scopo era quello di osservare alcuni effetti del fugo sul coccinellide
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Toftegaard, Tenna. "Temperature and the synchrony of plant-insect interactions." Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-131313.
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Increasing temperatures resulting from climate change have within recent years been shown to advance phenological events in a large number of species worldwide. Species can differ in their response to increasing temperatures, and understanding the mechanisms that determine the response is therefore of great importance in order to understand and predict how a warming climate can influence both individual species, but also their interactions with each other and the environment. Understanding the mechanisms behind responses to increasing temperatures are however largely unexplored. The selected study system consisting of host plant species of the Brassicaceae family and their herbivore Anthocharis cardamines, is assumed to be especially vulnerable to climatic variations. Through the use of this study system, the aim of this thesis is to study differences in the effect of temperature on development to start of flowering within host plant species from different latitudinal regions (study I), and among host plant species (study II). We also investigate whether different developmental phases leading up to flowering differ in sensitivity to temperature (study II), and if small-scale climatic variation in spring temperature influence flowering phenology and interactions with A. cardamines (study III). Finally, we investigate if differences in the timing of A. cardamines relative to its host plants influence host species use and the selection of host individuals differing in phenology within populations (study IV). Our results showed that thermal reaction norms differ among regions along a latitudinal gradient, with the host plant species showing a mixture of co-, counter- and mixed gradient patterns (study I). We also showed that observed differences in the host plant species order of flowering among regions and years might be caused by both differences in the distribution of warm days during development and differences in the sensitivity to temperature in different phases of development (study II). In addition, we showed that small-scale variations in temperature led to variation in flowering phenology among and within populations of C. pratensis, impacting the interactions with the butterfly herbivore A. cardamines. Another result was that the less the mean plant development stage of a given plant species in the field deviated from the stage preferred by the butterfly for oviposition, the more used was the species as a host by the butterfly (study IV). Finally, we showed that the later seasonal appearance of the butterflies relative to their host plants, the higher butterfly preference for host plant individuals with a later phenology, corresponding to a preference for host plants in earlier development stages (study IV). For our study system, this thesis suggest that climate change will lead to changes in the interactions between host plants and herbivore, but that differences in phenology among host plants combined with changes in host species use of the herbivore might buffer the herbivore against negative effects of climate change. Our work highlights the need to understand the mechanisms behind differences in the responses of developmental rates to temperature between interacting species, as well as the need to account for differences in temperature response for interacting organisms from different latitudinal origins and during different developmental phases in order to understand and predict the consequences of climate change.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.
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DeGomez, Tom, and Melanie Lenart. "Management of Forests and Woodlands (Climate Change and Variability in Southwest Ecosystems Series)." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2006. http://hdl.handle.net/10150/146920.
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4 pp.This is part of a series of publications on climate change and forests/woodlands
Climate change may have dramatic effects on Arizona's forests and woodlands. Wildfires and insects may become of greater concern. Plant species will likely shift in elevation to adapt to the warming conditions.
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Sjödin, N. Erik. "Pollinating insect responses to grazing intensity, grassland characteristics and landscape complexity : behaviour, species diversity and composition /." Uppsala : Dept. of Ecology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200755.pdf.
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Hersch, Erika I. "Evidence for hybridization between three Indian paintbrush species : ecological implications and evolutionary scenarios /." view abstract or download file of text, 2007. http://proquest.umi.com/pqdweb?did=1432774901&sid=1&Fmt=2&clientId=11238&RQT=309&VName=PQD.
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Thesis (Ph. D.)--University of Oregon, 2007.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 201-241). Also available for download via the World Wide Web; free to University of Oregon users.
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Bouchard, Patrice. "Insect diversity of four alvar sites on Manitoulin Island, Ontario." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0004/MQ44130.pdf.
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Wigfull, Patrick. "Geographical determinants of insect species diversity in the Hawaiian and Galápagos archipelagos, a biogeographical analysis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22146.pdf.
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Wigfull, Patrick (Patrick John) 1969 Carleton University Dissertation Biology. "Geographical determinations of insect species diversity in the Hawaiian and Galapagos archipelagos; a biogeographical analysis." Ottawa.:, 1997.
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Baker, Amanda J. "Comparing the effects of the exotic cactus-feeding moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) and a native cactus-feeding moth, Melitara prodenialis (Walker) (Lepidoptera: Pyralidae) on two species of Florida Opuntia." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001801.
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Fernandez-Conradi, Pilar. "Diversité des arbres et résistance des forêts aux invasions biologiques : application au chataignier et son complexe de bioagresseurs exotiques, chancre (Cryphonectria parasitica) et cynips (Dryocosmus Kuriphilus)." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0940/document.
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Les plantes sont au centre d’une grande diversité d’interactions biotiques entre organismes plus ou moins proches qui les exploitent en tant que ressources. L’objectif de cette thèse a été de comprendre comment les infections fongiques de la plante et la diversité des arbres en forêt modifient les interactions arbres-insectes. Nous avons tout d’abord effectué une méta-analyse pour poser le cadre théorique des effets indirects des infections fongiques sur les insectes herbivores associés aux mêmes plantes hôtes. L'effet de l’infection préalable des plantes par les champignons sur les préférences et performances des insectes s’avère généralement négatif. Cependant, la magnitude de cet effet délétère varie selon le mode de vie du champignon, la guilde trophique de l’insecte et la spatialité des interactions (interactions locales vs distantes). Nous avons ensuite analysé de façon empirique les interactions tripartites entre le châtaignier européen (Castanea sativa) et deux de ses bioagresseurs exotiques: le cynips (Dryocosmus kuriphilus), insecte galligène, et Cryphonectria parasitica, champignon pathogène responsable de la maladie du chancre. L'effet sur les taux d’infestation par le cynips de la composition spécifique en essences forestières des forêts de châtaigniers atteintes de chancre a été également étudié. Afin d'identifier les mécanismes sous-jacents aux effets de la diversité des forêts sur cet insecte invasif, les communautés d'insectes parasitoïdes et de champignons endophytes présents dans les galles ont été décrites. Les taux d’infection par le cynips étaient plus faibles dans les mélanges de châtaignier avec du chêne et du frêne que dans des parcelles de châtaignier monospécifiques ou dans les mélanges avec du pin. La composition des forêts influence aussi la composition des communautés de parasitoïdes associés aux galles du cynips mais pas leur abondance, richesse ou diversité. Les communautés de champignons endophytes des galles, étudiées par des méthodes de séquençage de nouvelle génération, sont indépendantes de la composition forestière. Par contre, celles présentes dans les galles différent fortement de celles des tissus foliaires adjacents. Nous avons ainsi apporté de nouvelles preuves que la diversité des plantes et les champignons pathogènes sont des facteurs clés déterminant les interactions plantes-insectes. Etudier comment les plantes interagissent avec leurs insectes et champignons associés, et les mécanismes sous-jacents à l’effet de la diversité des plantes sur ces interactions, doit permettre de mieux comprendre les relations entre diversité et fonctionnement des écosystèmes et de proposer des applications pour la gestion des bio-agresseurs forestiers natifs et exotiquesPlants are the playground of a large diversity of biotic interactions between related and unrelated organisms exploiting them as common resources. The aim of this thesis was to understand how plant-insect interactions vary with fungal infection of their host plant and plant diversity. I first performed a meta-analysis to provide a theoretical background for plant-mediated effects of fungal infection on herbivorous insects. Overall, I found a negative plant-mediated effect of fungi on both insect preference and performance. However, this effect varied according to fungus lifestyle, insect feeding guild and spatial location of the interactions (local vs distant). Then I experimentally tested plant-fungus-insect tripartite interactions in the particular case of exotic bio-aggressors of the European chestnut (Castanea sativa): the Asian chestnut Gall Wasp (ACGW, Dryocosmus kuriphilus), and the fungal pathogen Cryphonectria parasitica, the causal agent of chestnut blight. I performed an observational study, in natural chestnut forest stands in Italy, where I tested how ACGW infestation rates vary with the tree species composition. I also investigated the mechanisms underlying plant diversity effects on the invasive pest, with a particular focus on its natural enemies such as insect parasitoids and endophytic fungi. ACGW infestation rates was lower in oak and ash chestnut mixtures compared to monocultures or pine-chestnut mixtures. Plot composition also influenced ACGW parasitoid community composition but not their abundances, diversity or richness. Endophytic communities of galls, described by using next generation sequencing methods, did not vary with plot composition. However, they strongly differed from surrounding leaf tissues. We thus provided evidence that plant diversity and fungal pathogens are key drivers of plant-insect interactions. Understanding how plants interact with associated insects and fungi, and mechanisms underlying plant diversity effect on these interactions, will improve our knowledge on diversity-ecosystem functioning relationships and will have practical applications for the management of native and exotic forest pests
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Allen, Christine D. "AN ASSESSMENT OF THE INVASIVE POISON HEMLOCK AND ITS INSECT ASSOCIATES IN KENTUCKY." UKnowledge, 2013. http://uknowledge.uky.edu/entomology_etds/4.
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Poison hemlock, Conium maculatum (Apiaceae), is an invasive plant in North America with a unique toxic chemistry. Previous research on this plant has focused on identifying herbivores as potential biological control agents or describing the toxic plant alkaloids. However, none have examined the role of higher trophic levels in the food web surrounding poison hemlock. Generalist predators and food web interactions are an important component of studies investigating invasion effects, as plant or animal introductions can alter ecosystem functioning. In this study, predators in poison hemlock were sampled at the foliar and epigeal levels, resulting in 956 Carabidae and 321 Coccinellidae being collected. Predator connectedness to plant resources was quantified using molecular gut-content and chemical analyses. Foliar Harmonia axyridis (Coccinellidae) contained aphid DNA and plant chemicals, while Harpalus pensylvanicus (Carabidae) only contained alkaloids, suggesting that the ground predators were obtaining plant chemicals via alternative prey. Feeding trials between H. axyridis and their potentially toxic prey, Hyadaphis foeniculi (Aphididae), revealed that the exotic predator shows faster development when consuming aphids from poison hemlock compared to alternative diets. This study reveals that three Eurasian species may be facilitating one another, illustrating the importance of continued examination of invasive species interactions.
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Avanesyan, Alina. "Native versus Exotic Grasses: The Interaction between Generalist Insect Herbivores and Their Host Plants." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406808876.
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Sanford, Monte Paul. "Using insect responses to anthropogenic disturbance to improve land management and conservation planning decisions." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3289458.
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Theißinger-Theobald, Kathrin [Verfasser]. "Comparative phylogeography of two co-distributed arctic-alpine freshwater insect species in Europe / Kathrin Theißinger-Theobald." Mainz : Universitätsbibliothek Mainz, 2011. http://d-nb.info/102318608X/34.
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Bouwer, Marc Clement. "Identication of semiochemicals from four major insect pests of Eucalyptus and Pinus species in South Africa." Thesis, University of Pretoria, 2014. http://hdl.handle.net/2263/78160.
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The chemical ecology for key insect pests in South Africa's commercial Pinus and Eucalyptus
plantations are explored in this thesis. The main aim was to discover and
characterize semiochemical compounds that explain certain behaviours of the insects
involved, and that could potentially be exploited in future for the manipulation of the
insects' behaviour. Such formulations are sought after because they can be applied in
environmentally friendly pest management techniques. Semiochemical interactions were
studied in four di erent biological systems. These included the sex pheromone communication
system for the Cossid moth, Coryphodema tristis; allelochemical interactions
between the Eucalyptus weevil Gonipterus spp. and their Eucalyptus host; allelochemical
interactions between Sirex noctilio's, symbiotic fungus, Amylostereum areolatum and
its biological control agent Ibalia leucospoides; and allelochemical interactions between
the egg clutches of Thaumastocoris peregrinus and its biological control agent Cleurocoides
noackae. Semiochemical compounds were found and identi ed through analysis
techniques that included gas chromatography coupled to electroantennography (GCEAD)
and gas chromatography coupled to mass spectrometry (GC-MS). Some of these
semiochemical interactions were complex involving combinations of di erent chemical
cues, such as the host recognition cues identi ed for Gonipterus species and potential
cues between T. peregrinus females and their egg clutches. Other speci c interactions
were found to be simpler and relied on a few speci c chemicals. These included the
sex pheromone communication between C. tristis adults and the interaction occurring
between female I. leucospoides wasps and the mutualistic fungus of their prey, namely
A. areolatum. Biological activity was investigated only for compounds with con rmed
identity and included the sex pheromones of C. tristis and some of the chemicals identi
ed from the egg clusters of T. peregrinus. These tests were conducted in laboratory
and eld conditions. Biological activity was proven for the identi ed sex pheromone of
C. tristis during eld trials conducted in 2011 and 2013. One of the chapters was published
and another submitted for publication in a peer reviewed journal. Two provisional
patents were also registered from this work.Thesis (PhD)--University of Pretoria, 2014.
Chemistry
PhD
Unrestricted
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Nakadai, Ryosuke. "Generation and maintenance of species diversity in leaf cone moths (Caloptilia) feeding on maples (Acer)." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225439.
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VanLaerhoven, Sherah Lynnette. "Successional biodiversity in insect species on buried carrion in the Vancouver and Cariboo regions of British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24261.pdf.
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Schorscher, Judith A. (Judith Anne). "Insect predators of larval Simulium damnosum Theobald, vector of onchocerciasis, and other Simulium species in Southern Sudan." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63254.
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Heads, P. A. "The influence of predators on the behaviour and feeding ecology of prey species in two insect communities." Thesis, University of York, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370733.
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Leggett, J. E. "The Influence of ULV Malathion, Applied for Boll Weevil Control, on Other Pest and Beneficial Species in Arizona Cotton Fields." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/208331.
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Bass, Katherine Ann. "Resource partitioning in the multi-species interaction between a host plant, a parasitic angiosperm and an insect herbivore." Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.666763.
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Kesavaraju, Banugopan Juliano Steven A. "Behavioral interactions between predator and prey and their influence on an invasive species in container habitats." Normal, Ill. : Illinois State University, 2007. http://proquest.umi.com/pqdweb?index=0&did=1390287471&SrchMode=1&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1202751489&clientId=43838.
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Thesis (Ph. D.)--Illinois State University, 2007.Title from title page screen, viewed on February 11, 2008. Dissertation Committee: Steven A. Juliano (chair), Diane L. Byers, L. Philip Lounibos, Charles F. Thompson, William L. Perry. Includes bibliographical references (leaves 152-163) and abstract. Also available in print.
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Rethwisch, Michael D., Charles W. McDaniel, and Gary Major. "Comparison of Capture, Capture and Thiodan, Malathion and Pounce Insecticides for Control of Two Aphid Species on Broccoli Seed." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/214523.
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Du, Chen. "Global analysis of microrna species in the gall midge Mayetiola destructor." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20375.
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Master of ScienceEntomology
Ming-Shun Chen
Robert "Jeff" J. Whitworth
MicroRNA (miRNA) plays a role in nearly all the biological pathways and therefore may provide opportunities to develop new means to combat the Hessian fly, Mayetiola destructor, a destructive pest of wheat. This study presents a comprehensive analysis of miRNA species via deep-sequencing samples from Hessian fly second instar larvae, pupae and adults. A total of 921 unique miRNA species were identified from approximately 30 million sequence reads. Among the 921 miRNA species, only 22 were conserved among Hessian fly and other insect species, and 242 miRNA species were unique to Hessian fly, the remaining 657 share certain sequence similarities with pre-miRNA genes identified from various insect species. The abundance of the 921 miRNA species based on sequence reads varies greatly among the three analyzed stages, with 20 exclusively expressed in adults, two exclusively expressed in pupae and two exclusively expressed in second instar larvae. For miRNA species expressed in all stages, 722 were with reads lower than 10. The abundance of the remaining 199 miRNA species varied from zero to more than eight-fold differences among different stages. Putative miRNA-encoding genes were analyzed for each miRNA species. A single putative gene was identified for 594 miRNA species. Two putative genes were identified for 138 miRNA species. Three or more putative genes were identified for 86 miRNA species. The three largest families had 14, 23 and 34 putative coding genes, respectively. No gene was identified for the remaining 103 miRNA species. In addition, 1516 putative target genes were identified for 490 miRNA species based on known criteria for miRNA targets. The putative target genes are involved in a wide range of processes from nutrient metabolism to encoding effector proteins. Analysis of the expression patterns of miRNA and pre-miRNA for the miRNA family PC-5p-67443, which contains 91 genes, revealed that miRNA and pre-miRNA were expressed differently in different developmental stages, suggesting that different isogenes are regulated by different mechanisms, or pre-miRNAs had other functions in addition to as an intermediate for miRNA biogenesis. The large set of miRNA species identified here provides a foundation for future research on miRNA functions in Hessian fly and for comparative studies in other species. The differential expression patterns between a pre-miRNA and its encoded mature miRNA in a multigene family is an initial step toward understanding the functional significance of isogenes in dramatically expanded miRNA families.