Dissertations / Theses on the topic 'Tryonii'

Queensland fruit fly is a destructive horticultural insect pest. Knowing the age-structure of fly populations, that is the relative proportion of young, middle-age, and old-age flies within a population at a given time, is critical for effective management. The thesis combined behavioural ecology with a novel mathematical analysis to identify the seasonal changes in the age of a wild Queensland fruit fly population. The study showed that the abundance and age-structure of the fly changed predictably with the season, strongly suggestive of an endogenous mechanism that helps the fly cope with seasonal changes in resource availability.

This project elucidated functional role of phytochemicals used in the management of pest fruit flies. Comparative behavioural, physiological and genomic approaches revealed that phytochemicals are mediating reproductive fitness by changing pheromonal compound males release and by making them physiologically more active. The possible mechanistic functions are that the phytochemicals act as a pheromone booster and as an energy supplement.

Doctor of Philosophy
A number of types of molecular polymorphisms can be used for studying genetic relationship and evolutionary history. Microsatellites are hypervariable and can be very useful tools to determine population structure, distinguish sibling species, as well as verifying parental relationships and pedigrees. However, while microsatellite polymorphisms are useful for solving relationships between populations within a species, relations among species or genera will probably be obscured due to a high degree of homoplasy —identity arising from evolutionary convergence not by descent. For long range evolutionary history, such as phylogeny from old world monkey to human, mtDNA markers may be better candidates. The aim of this thesis is to assess molecular polymorphisms of different types and their optimal use in different situations. Two widely separated taxa were used for testing –the green monkey Chlorocebus sabaeus, and the sibling dipteran flies Bactrocera tryoni and B. neohumeralis, known collectively as the Queensland fruit fly. In the present study a complete 16,550 bp mtDNA sequence of the green monkey Chlorocebus sabaeus is reported for the fist time and has been annotated (Chapter 2). Knowledge of the mtDNA genome contributes not only to identification of large scale single nucleotide polymorphisms (SNPs) (Chapter 4) or other mtDNA polymorphisms development, but also to primate phylogenetic and evolutionary study (Chapter 3). Microsatellites used for the green monkey paternity and pedigree studies were developed by cross-amplification using human primers (Chapter 5). For studies of population structure and species discrimination in Queensland fruit fly (Chapter 7), microsatellites were isolated from a genomic library of Bactrocera tryoni (Chapter 6) The total length of 16550 bp of complete mtDNA of the green monkey C. sabaeus, which has been sequenced and annotated here, adds a new node to the primate phylogenetic tree, and creates great opportunity for SNP marker development. The heteroplasmic region was cloned and five different sequences from a single individual were obtained; the implication of this are discussed. The phylogenetic tree reconstructed using the complete mtDNA sequence of C. sabaeus and other primates was used to solve controversial taxonomic status of C. sabaeus. Phylogenies of primate evolution using different genes from mtDNA are discussed. Primate evolutionary trees using different substitution types are compared and the phylogenetic trees constructed using transversions for the complete mtDNA were found close to preconceived expectations than those with transversions + transitions. The sequence of C. sabaeus 12SrRNA reported here agrees with the one published by ven der Kuyl et al. (1996), but additional SNPs were identified. SNPs for other regions of mtDNA were explored using dHPLC. Twenty two PCR segments for 96 individuals were tested by dHPLC. Fifty five SNPs were found and 10 haplogroups were established. Microsatellite markers were used to construct a genealogy for a colony of green monkeys (C. sabaeus) in the UCLA Vervet Monkey Research Colony. Sixteen microsatellites cross-amplified from human primers were used to conduct paternity analysis and pedigree construction. Seventy-eight out of 417 offspring were assigned paternity successfully. The low success rate is attributed to a certain proportion of mismatches between mothers and offspring; the fact that not all candidate fathers were sampled, the limitations of microsatellite polymorphisms; and weakness of the exclusion method for paternity assessment. Due to the low success rate, the pedigree is split into a few small ones. In a complicated pedigree composed of 75 animals and up to four generations with multiple links a power male mated with 8 females and contributed 10 offspring to the pedigree. Close inbreeding was avoided. Population structure within two species of Queensland fruit fly Bactrocera tryoni and Bactrocera neohumeralis (Tephritidae: Diptera) is examined using microsatellite polymorphisms. Queensland fruit flies B. tryoni and B. neohumeralis are sympatric sibling species that have similar morphological and ecological features. They even share polymorphism at the molecular level. Mating time difference is the main mechanism by which they maintain separate species. In the present study, 22 polymorphic and scorable microsatellites were isolated from B. tryoni and tested in the two species sampled from sympatric distribution areas. Pairwise genetic distance analysis showed explicit differentiation in allele frequencies between the two species, but very weak differences between conspecific populations. Gene flow is higher within B. tryoni than within B. neohumeralis, and gene exchange between the two species exists. An averaging linkage clustering tree constructed by UPGMA showed two major clusters distinguishing the two species, and it appears that population structure is highly correlated with geographic distance. The relationship between molecular markers, evolution, and selection are discussed using comparative studies within two large taxa: primate and insect. The degree of conservation and polymorphism in microsatellites varies between taxa, over evolutionary time.

Bactrocera tryoni, the Queensland fruit fly, is established along the entire Australian east coast. It is a major pest of horticulture and arguably the worst horticultural insect pest in Australia. Adult flies lay eggs into fruit and resultant larvae feed on the flesh of the fruit. The population biology of B. tryoni has been well studied in temperate regions, where it has been established that climatic factors, particularly temperature and rainfall, limit population growth. In contrast, in subtropical and tropical regions, the population dynamics of the fly have been little studied. This thesis investigates the fly's phenology and abundance changes across subtropical and tropical Queensland and asks what factors govern the population cycles of B. tryoni in this state. Winter breeding and abundance of the fly, a component of the seasonal cycle which in south-east Queensland is fundamentally different from that observed in temperate Australia, is also investigated. A historical, extensive multi-year and multi-site trapping data set with from across Queensland was analysed to look at the effects of temperature, rainfall and relative humidity on B. tryoni trap catch. Trap data was further compared with the predicted phenology data generated by a DYMEX® based B. tryoni population phenology model. The phenology model used was based on a previously published model, but was also modified to more explicitly look at the effects of host plant availability and the presence or absence of non-reproductive over-wintering flies. Over-wintering field cage studies and a winter-spring field trapping study, both carried out in Brisbane, supplied additional data on B. tryoni's population abundance and capacity to breed during winter in the subtropics. Results show significant variation of monthly fly abundance for nine sites across Queensland. Abundance changed across sites in non-predictable ways. Annual population phenology within a site was, for some sites, highly consistent from year to year, but inconsistent for other sites. All sites in the subtropics showed some form of population depression during the cooler months, but breeding was continuous, albeit reduced at nearly all sites. Some tropical sites, where the climate is regarded as highly favourable for B. tryoni, still showed dramatic peaks and troughs in annual population abundance. There were relatively few significant correlations observed between weather factors and fly populations for any site. Output from the DYMEX population model suggested that fruit availability is a major driver of population dynamics in the tropical north of the state, while weather is more important in the subtropical south. The population dynamics of B. tryoni at sites along the central Queensland coast, where it is assumed that a mix of both weather and host fruit availability drive local populations, were poorly captured by the population model. Field cage results showed that B. tryoni successfully bred during winter in Brisbane, with pupal emergence starting in mid-winter (1st week of August), peaking in early spring (2nd week of September). Trap catch at orchards in Brisbane increased with increasing temperature and fruit availability, but diminished with decreasing temperature and fruit availability. The results suggest that B. tryoni has an optimal climate for population growth in the tropics, but fruit availability for offspring production limits population growth. In the subtropics however, both climate and fruit availability determine the population size. Winter temperatures are marginal for B. tryoni population growth in the subtropics.

Bactrocera tryoni, the Queensland fruit fly, is established along the entire Australian east coast. It is a major pest of horticulture and arguably the worst horticultural insect pest in Australia. Adult flies lay eggs into fruit and resultant larvae feed on the flesh of the fruit. The population biology of B. tryoni has been well studied in temperate regions, where it has been established that climatic factors, particularly temperature and rainfall, limit population growth. In contrast, in subtropical and tropical regions, the population dynamics of the fly have been little studied. This thesis investigates the fly's phenology and abundance changes across subtropical and tropical Queensland and asks what factors govern the population cycles of B. tryoni in this state. Winter breeding and abundance of the fly, a component of the seasonal cycle which in south-east Queensland is fundamentally different from that observed in temperate Australia, is also investigated. A historical, extensive multi-year and multi-site trapping data set with from across Queensland was analysed to look at the effects of temperature, rainfall and relative humidity on B. tryoni trap catch. Trap data was further compared with the predicted phenology data generated by a DYMEX® based B. tryoni population phenology model. The phenology model used was based on a previously published model, but was also modified to more explicitly look at the effects of host plant availability and the presence or absence of non-reproductive over-wintering flies. Over-wintering field cage studies and a winter-spring field trapping study, both carried out in Brisbane, supplied additional data on B. tryoni's population abundance and capacity to breed during winter in the subtropics. Results show significant variation of monthly fly abundance for nine sites across Queensland. Abundance changed across sites in non-predictable ways. Annual population phenology within a site was, for some sites, highly consistent from year to year, but inconsistent for other sites. All sites in the subtropics showed some form of population depression during the cooler months, but breeding was continuous, albeit reduced at nearly all sites. Some tropical sites, where the climate is regarded as highly favourable for B. tryoni, still showed dramatic peaks and troughs in annual population abundance. There were relatively few significant correlations observed between weather factors and fly populations for any site. Output from the DYMEX population model suggested that fruit availability is a major driver of population dynamics in the tropical north of the state, while weather is more important in the subtropical south. The population dynamics of B. tryoni at sites along the central Queensland coast, where it is assumed that a mix of both weather and host fruit availability drive local populations, were poorly captured by the population model. Field cage results showed that B. tryoni successfully bred during winter in Brisbane, with pupal emergence starting in mid-winter (1st week of August), peaking in early spring (2nd week of September). Trap catch at orchards in Brisbane increased with increasing temperature and fruit availability, but diminished with decreasing temperature and fruit availability. The results suggest that B. tryoni has an optimal climate for population growth in the tropics, but fruit availability for offspring production limits population growth. In the subtropics however, both climate and fruit availability determine the population size. Winter temperatures are marginal for B. tryoni population growth in the subtropics.

Fruit flies are the insects which cause maggots in your backyard fruit and vegetables. They are not just a nuisance to gardeners, but the single greatest insect threat to commercial and subsistence fruit growers throughout Asia, Australia and the Pacific. Queensland fruit fly, the focus of this PhD, costs Australia an estimated $100million per year. I focused specifically on how Queensland fruit fly uses different commercial citrus varieties. I identified specific plant related mechanisms which increase a fruit’s resistance to fruit fly attack. This information can be used by plant breeders to make fruit less prone to fruit fly damage.

Queensland fruit fly is Australia’s most destructive horticultural insect pest. The flies need to mate to successfully reproduce, but there remained significant gaps in knowledge about how they find and select mates. I showed that male and female flies likely use physical landmarks to find each other in the environment. Having found potential mates, I described their fine-scale courtship behaviour and demonstrated that young, large male flies are most successful at securing a mate. I also made significant advances in our understanding of the potential for close-range chemical communication to play a role in mate identification and selection. This research directly informs sustainable management strategies against this pest.

Fruit flies are serious pests of fruit around the world, as their maggots destroy fruit by feeding within them. An important non-pesticide control option for fruit flies is the use of natural enemies. This study investigated the role of memory and learning in the host searching behaviour of one such natural enemy, the small wasp, Diachasmimorpha kraussii. This wasp is native to Australia and attacks our most serious fruit fly pest, the Queensland Fruit Fly. This research studied fundamental insect behaviour, but produced specific recommendations for the more effective use of Diachasmimorpha kraussii for sustainable pest management.

The Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), a major pest of horticulture in eastern Australia, is a relatively poor coloniser of new habitat. This thesis examines behavioural properties that might limit the ability of B. tryoni to establish new populations. As the potential for B. tryoni to establish an outbreak population may be most directly limited by mechanisms associated with dispersal and mating behaviour, these two factors were the focus of this research project. The relevance of dispersal and mating behaviour for control of outbreak populations was assessed. Dispersal (i) Dispersal patterns of males and females are not different. Dispersal of post-teneral male B. tryoni from a point within an orchard near Richmond, New South Wales, was monitored following temporally replicated releases. Application of sterile insect technique (SIT) requires knowledge of dispersal from a release point so that effective release rates can be determined. In addition, dispersal following introduction to new habitat can lead to low or negative population growth and an Allee effect. In Spring and Autumn, 2001 � 2003, three different strains of B. tryoni were released: (1) wild flies reared from infested fruit collected in the Sydney Basin; (2) a laboratory-reared strain with a colour mutation (white marks); and (3) sterile flies obtained by gamma-irradiation of a mass-reared strain. Dispersal was monitored using a grid of traps baited with the male attractant, cuelure. During the majority of releases, flies were massmarked using a self-marking technique and fluorescent pigment powder to enable identification of recaptured flies. A preliminary study found that fluorescent pigment marks had no effect on adult survival and marks did not fade significantly in the laboratory over a period of five weeks after eclosion. As cuelure repels inseminated sexually mature female B. tryoni, unbaited, coloured flat sticky traps, and black and yellow sticky sphere traps baited with a food lure (protein autolysate solution) were used to supplement traps baited with cuelure. The effectiveness of these two sticky trap types was assessed, and recaptures used to compare patterns of dispersal from a release point by male and female B. tryoni. Fluorescent yellow (chartreuse), green, and clear unbaited flat sticky traps were relatively ineffective for monitoring dispersal of sterile male and female B. tryoni, recapturing only 0.1% of released sterile flies. Monitoring dispersal with sticky ball traps baited with protein autolysate solution was more successful, with yellow spheres and black spheres recapturing 1.7% and 1.5%, respectively. Trap colour had no effect on recaptures on flat sticky traps or sticky spheres. Equal recapture rates on yellow and black sticky sphere traps suggests that the odour of yeast autolysate solution was more important than colour for attraction of post-teneral flies to traps. Using the results of recaptures on odoriferous black and yellow sticky sphere traps within one week of release, regression equations of male and female recaptures per trap were found to be similar (Figure 4-3). This is the first study to clearly indicate that post-teneral dispersal patterns of male and female B. tryoni released from a point do not differ, enabling the use of existing models to predict density of both sexes of B. tryoni following post-teneral dispersal. (ii) Males disperse further in Spring than in Autumn, but this is not temperature-related. Analysis of replicated recaptures in traps baited with cuelure revealed that dispersal of male B. tryoni in an orchard near Richmond, New South Wales, was higher in Spring than in Autumn (Figure 5-6). As the maximum daily temperature was significantly higher in Spring than in Autumn this result was unexpected, since earlier studies have found that B. tryoni disperse at the onset of cool weather in search of sheltered over-wintering sites. Dispersal of post-teneral B. tryoni may have been affected by habitat suitability; it was found that seasonal trends in dispersal could have been influenced by local habitat variables. Low mean dispersal distances in Autumn may be explained by the presence of fruiting hosts in the orchard, or the availability of resources required by over-wintering flies. There was no significant correlation between temperature and mean dispersal distance, suggesting that higher rates of dispersal cannot be explained by temperature-related increases in activity. Recapture rate per trap was significantly negatively correlated with increasing daily maximum and average temperature. This may have consequences for detection of B. tryoni outbreaks in quarantine areas due to reduced cuelure trap efficiency. (iii) Maturity and source variation affect dispersal and response to cuelure. This research indicated that most male and female B. tryoni do not disperse far from a release point, suggesting that an invading propagule would not spread far in the first generation. However, there is considerable variation in flight capability among individuals. Comparison of wild, laboratory-reared white marks, and gamma-irradiated sterile male B. tryoni indicated that mean dispersal distance and redistribution patterns were not significantly affected by fly origin. Despite no difference in dispersal distance from the release point, recaptures of wild and sterile males per Lynfield trap baited with cuelure were highest within one week after release, whereas recaptures of white marks males per trap increased in the second week. This result may offer evidence to support the hypothesis that sterile male B. tryoni respond to cuelure at an earlier age. Rearing conditions used to produce large quantities of males for sterilisation by gamma-irradiation may select for earlier sexual maturity. Mating Behaviour (i) Density and sex ratio do not affect mating, except at low densities. Demographic stochasticity in the form of sex ratio fluctuations at low population density can lead to an observed Allee effect. The effect of local group density and sex ratio on mating behaviour and male mating success of a laboratory-adapted strain of B. tryoni was examined in laboratory cages. In the laboratory-adapted strain of B. tryoni used in this study, a group of one female and one male was sufficient for a good chance of mating success. The proportion of females mated and male mating success was not significantly affected by density or sex ratio, although variability in male mating success was higher at low density. This could indicate that mating success of B. tryoni can be reduced when local group density is low owing to decreased frequency in encounters between males and females. (ii) Mass-reared males exhibit aberrant mating behaviour, but this does not reduce mating success. Strong artificial selection in mass-rearing facilities may lead to decreased competitiveness of sterile males released in SIT programs as a result of alteration or loss of ecological and behavioural traits required in the field. The effects of domestication and irradiation on the mating behaviour of males of B. tryoni were investigated by caging wild, mass-reared and sterile (mass-reared and gammairradiated) males with wild females. Mating behaviour of mass-reared males was different from that of wild males, but behaviour of wild and sterile males was similar. Mass-reared males were found to engage in mounting of other males much more frequently than wild and sterile males, and began calling significantly earlier before darkness. Male calling did not appear to be associated with female choice of mating partners, although this does not exclude the possibility that calling is a cue used by females to discriminate between mating partners. Conditions used to domesticate and rear large quantities of B. tryoni for SIT may select for an alternative male mating strategy, with mass-reared males calling earlier and exercising less discrimination between potential mating partners. Despite differences in behaviour of wild, mass-reared and sterile males, frequency of successful copulations and mating success were similar. (iii) Pheromone-calling by males was increased in larger aggregations but this did not result in significantly more female visits. Finally, large laboratory cages with artificial leks were used to investigate the importance in B. tryoni of male group size for female visitation at lek sites and initiation of male pheromone-calling. Calling propensity of male B. tryoni was increased by the presence of conspecific males. Females visited the largest lek more frequently than single males, but there was no correlation between lek size and female visitation. Female B. tryoni had a limited capacity to perceive a difference between the number of calling males; female visitation at leks was only weakly associated with male calling, suggesting that lek size and the number of pheromone-calling males may not be the only factor important in locating mates in B. tryoni. The weak, but positive correlation between male calling and female visitation may indicate that passive attraction maintains lek-mating in B. tryoni. Further studies are essential on mating behaviour of B. tryoni, including identification of male mating aggregations in the field, measurement of habitat variables associated with male aggregations, the influence of density on wild B. tryoni mating success, and the role of pheromone-calling, in order to optimise use of SIT for control of this pest.

Queensland fruit fly is Australia's most serious insect pest of horticulture. The fly lays its eggs into fruit, where they hatch into maggots which destroy the fruit. Understanding egg laying behaviour, known as oviposition, is a critical but under-researched aspect of fruit fly biology. This thesis focused on three aspects of oviposition: the role of fruit peel as a physical barrier to oviposition; the quality of fruit for maggot development; and the structure and wear of the egg laying organ – the ovipositor. Results showed that flies selected fruit based on their suitability for offspring survival, not because of the softness or hardness of fruit peel. Previously reported use of holes or wounds in fruit peel by ovipositing females was determined to be a mechanism which saved the female time, not a mechanism to reduce ovipositor wear. The results offer insights into the evolution of host use by fruit flies and their sustainable management.

Fruit flies are insect pests which cause devastating losses to fruit and vegetable crops around the globe. Replacing pesticides with natural enemies is a preferred option for their sustainable control. This study investigated the abundance, distribution and biology of two such natural enemies: the small parasitic wasps Fopius arisanus and Diachasmimorpha kraussii. F. arisanus was identified as having more successful characteristics than D. kraussii, making it the most common fruit fly parasitod in southeast Queensland. The research lead to advances in understanding insect behaviour as well as recommendations for better utilisation of parasitoids for fruit fly control.

En la implantología moderna se han propuesto nuevas técnicas, entre ellos, los implantes inmediatos a la exodoncia; provisionalización inmediata y la carga inmediata, que han supuesto una modificación de los protocolos tradicionales aportados en los trabajos de Brånemark. El uso de implantes dentales para restablecer la función y estética natural tras la pérdida de un diente se convirtió en uno de los mayores desafíos de la odontología restauradora. La colocación de implantes dentales de forma inmediata pasó a formar parte integral de un protocolo diseñado para el mantenimiento de un contorno gingival armónico. Aunque la literatura describe que la colocación y la provisionalización inmediata de los implantes colocados en alvéolos postexodoncia no ofrecen conclusiones definitivas, el creciente número de estudios clínicos demuestra que existen resultados de éxito similares a los registrados para la colocación convencional del implante. La provisionalización inmediata es una realidad en la implantología actual, pero su éxito depende de la cuidadosa selección del caso, de un profundo conocimiento de los principios biológicos, de la precisión en las maniobras quirúrgico-protésicas y de respetar los principios biológicos de la reparación ósea. Diversos estudios han reportado altas tasas de éxito tras la restauración provisional de los implantes colocados inmediatamente después de la exodoncia así como de los implantes colocados en hueso cicatrizado. Además de eliminar la necesidad de una prótesis removible provisional, esta técnica también ha demostrado el potencial para la preservación de la arquitectura gingival y ósea existente. El objetivo de este estudio fue evaluar el porcentaje de supervivencia así como la pérdida ósea crestal interproximal de 43 implantes Tryon® sometidos a provisionalización inmediata. El grupo de estudio estuvo conformado por 43 pacientes de ambos sexos con la necesidad de rehabilitar la ausencia de un diente unitario. Los implantes fueron colocados en la región anterior y posterior de ambos maxilares, en el reborde alveolar cicatrizado (34 implantes) y inmediatos a la exodoncia (8 implantes). Todos los implantes recibieron un torque mínimo de inserción de 40 Ncm2 y tuvieron un seguimiento de seis meses. Realizamos el análisis radiográfico de la pérdida ósea crestal mediante la técnica radiográfica de paralelismo; las radiografías fueron analizadas y medidas por el programa Adobe Photoshop. En nuestro estudio el implante Tryon® tuvo un índice de éxito del 88,4%. A nivel mesial, la cresta ósea presentó una pérdida significativa de altura, pasando desde 0,458 ± 0,907 mm- hasta 0,932 ± 0,525 mm a los tres meses y 1,313 ± 0,678 a los 6 meses (p< 0.001). A nivel distal, la altura ósea disminuyó, también, de forma significativa desde 0,232 ± 0,373 mm. hasta 0,729 ± 0,594 mm. a los tres meses y 1,197 ± 0,677 mm. a los 6 meses (p<0.001). El mayor diámetro de implante y el mayor índice de placa bacteria presentaron un significativo índice de correlación negativa con la pérdida ósea en mesial a los 3 y 6 meses. Las variables longitud y torque de inserción del implante no presentaron ninguna correlación significativa con el nivel óseo alcanzado. El sexo del paciente, la densidad ósea, la colocación del implante en alveolos cicatrizados o en alveolos postextracción, la posición anterior o posterior del implante en maxilar o mandíbula, son variables que no influyeron de forma significativa en las pérdidas óseas mesial y distal. Los implantes sobre hueso cicatrizado o inmediatos a la exodoncia, sometidos a provisionalización inmediata, pueden tener resultados predecibles en cuando a porcentaje de supervivencia del implante, y unos patrones de reabsorción ósea interproximal similares a implantes con provisionalización diferida.
In the use of dental implants have been proposed new techniques, such as the placement immediately after extraction implants, immediate temporization and immediate loading, which implies a change in traditional protocols in the work of Brånemark. The use of dental implants to restore the natural function and beauty after the loss of a tooth has become one of the biggest challenges of restorative dentistry. The placement of dental implants immediately became an integral part of a protocol designed to maintain a harmonious gingival contour. Although the literature shows the position and timing of immediate implants placed in post-extraction sockets do not offer definitive conclusions, the wide number of clinical studies show that the results are similar to those reported for the successful placement of conventional technique. The immediate timing is now a reality in implantology, but its success depends on the careful selection of the case, a deep understanding of biological principles, precision-prosthetic surgical maneuvers and to respect the biological principles of bone repair. Several studies have reported high success rates after the temporary restoration of implants placed immediately after tooth extraction and implants placed in healed bone. Besides eliminating the need for a temporary removable implant, this technique has also demonstrated the potential preserving existing bone and gingival architecture. The objective of this study was to evaluate the survival rate and the loss of interproximal bone crest of 43 implants Tryon® subjected to immediate temporization. The study group consisted in 43 patients of both sexes with the need to rehabilitate the absence of a single tooth. The implants were placed in the anterior and posterior regions of both maxillary. On the alveolar ridge (34 implants), and immediately after extraction (8 implants). All implants received a minimum insertion torque of 40N/cm2 and were followed by six months. Radiographs realized with a parallel technique studied the crestal bone loss. They were analyzed using the software Adobe Photoshop. In our study, the implant Tryon® had a 88.4% success rate. The level of mesial bone crest showed a significant loss of height, from 0.458 ± 0.932 mm to 0.907 ± 0.525 mm (3months) and 1.313 ± 0.678 (6 months; p <0.001).The level of distal bone crest decreased significantly of 0.232 ± 0.373 mm to 0.729 ± 0.594 mm (3 months) and 1.197 ± 0.677 mm (6 months; p <0.001). The larger diameter and the highest plaque index rate showed a significant negative correlation index with bone loss in mesial at 3 and 6 months. The length and the insertion torque showed no significant correlation with bone level achieved. The sex of the patients, the bone density, the implant placement in bone healed or in post extraction socket, the anterior or posterior position of the implant in the maxilla or mandible, are variables that did not influence significantly the mesial and distal bone loss. In implants placed immediately after extraction or bone healed subject to immediate temporization, may have predictable results taking into account the implant survival rate, and similar interproximal reabsorption standards to implants with deferred temporization.

Fruit flies are major pests to a wide range of fruits and vegetables as their larvae cause damage and yield loss. To replace pesticide-based controls with more sustainable management approaches, we need to develop new generation technologies. This thesis focuses on molecular and whole-organism studies to investigate the interactions between Queensland fruit fly larvae and tomato fruit. Through molecular analysis, different mechanisms were identified to determine the susceptibility of various tomato varieties to fruit fly damage. The results pave the way for future studies on breeding for fruit resistance to fruit fly attack and sustainable pest management.

This study contributed to the body of research that supports a holistic model of afterschool learning through the design of an afterschool intervention that benefits elementary school students of low socioeconomic status. This qualitative study evaluated a science focused afterschool curriculum that was designed using principles from Risk and Resiliency Theory, academic motivation theories, science core ideas from the Next Generation Science Standards, and used environmental education philosophy. The research question of this study is: how does an outdoor and STEM based afterschool program impact at-risk students' self-efficacy, belonging and engagement and ability to apply conceptual knowledge of environmental science topics? The study collected information about the participants' affective experiences during the intervention using structured and ethnographic observations and semi-structured interviews. Observations and interviews were coded and analyzed to find patterns in participants' responses. Three participant profiles were developed using the structured observations and ethnographic observations to provide an in depth understanding of the participant experience. The study also assessed the participants' abilities to apply conceptual understanding of the program's science topics by integrating an application of conceptual knowledge task into the curriculum. This task in the form of a participant project was assessed using an adapted version of the Portland Metro STEM Partnership's Application of Conceptual Knowledge Rubric. Results in the study showed that participants demonstrated self-efficacy, a sense of belonging and engagement during the program. Over half of the participants in the study demonstrated a proficient understanding of program concepts. Overall, this holistic afterschool program demonstrated that specific instructional practices and a multi-modal science curriculum helped to support the social and emotional needs of at-risk children.

UNESCO established Sustainability Education as a top priority when it declared 2005 - 2014 to be the global decade for sustainability. Sustainability education can be implemented in outdoor programs such as nature summer camps in order to build environmental stewardship and ecological literacy in counselors and campers. This study sought to determine the extent to which an ecology and leadership training given to assistant counselors at Tryon Creek State Natural Area day camp achieved the goals of sustainability education--for the assistant counselors to learn about ecology, develop stewardship attitudes and behaviors toward the environment, and become positive role models for the campers in their care. Knowledge and environmental stewardship attitudes and behaviors of the counselors were assessed using surveys, interviews, and training journals. A statistically significant difference was found between pre and posttest scores on a survey measuring knowledge of Pacific Northwest ecology, but no significant difference was found between the pre and posttest scores on an environmental attitudes survey, possibly due to a ceiling effect. Interviews revealed that participants learned about invasive species, Oregon flora and fauna, and stream ecology over the summer. Despite the results on the attitudes survey, interviewees reported greater environmental awareness at the end of the summer as well as a greater sense of place in nature and a desire to continue working with children in an outdoor setting.

International market access for fresh commodities is regulated by international accepted phytosanitary guidelines, the objectives of which are to reduce the biosecurity risk of plant pest and disease movement. Papua New Guinea (PNG) has identified banana as a potential export crop and to help meet international market access requirements, this thesis provides information for the development of a pest risk analysis (PRA) for PNG banana fruit. The PRA is a three step process which first identifies the pests associated with a particular commodity or pathway, then assesses the risk associated with those pests, and finally identifies risk management options for those pests if required. As the first step of the PRA process, I collated a definitive list on the organisms associated with the banana plant in PNG using formal literature, structured interviews with local experts, grey literature and unpublished file material held in PNG field research stations. I identified 112 organisms (invertebrates, vertebrate, pathogens and weeds) associated with banana in PNG, but only 14 of these were reported as commonly requiring management. For these 14 I present detailed information summaries on their known biology and pest impact. A major finding of the review was that of the 14 identified key pests, some research information occurs for 13. The single exception for which information was found to be lacking was Bactrocera musae (Tryon), the banana fly. The lack of information for this widely reported ‘major pest on PNG bananas’ would hinder the development of a PNG banana fruit PRA. For this reason the remainder of the thesis focused on this organism, particularly with respect to generation of information required by the PRA process. Utilising an existing, but previously unanalysed fruit fly trapping database for PNG, I carried out a Geographic Information System analysis of the distribution and abundance of banana in four major regions of PNG. This information is required for a PRA to determine if banana fruit grown in different parts of the country are at different risks from the fly. Results showed that the fly was widespread in all cropping regions and that temperature and rainfall were not significantly correlated with banana fly abundance. Abundance of the fly was significantly correlated (albeit weakly) with host availability. The same analysis was done with four other PNG pest fruit flies and their responses to the environmental factors differed to banana fly and each other. This implies that subsequent PRA analyses for other PNG fresh commodities will need to investigate the risk of each of these flies independently. To quantify the damage to banana fruit caused by banana fly in PNG, local surveys and one national survey of banana fruit infestation were carried out. Contrary to expectations, infestation was found to be very low, particularly in the widely grown commercial cultivar, Cavendish. Infestation of Cavendish fingers was only 0.41% in a structured, national survey of over 2 700 banana fingers. Follow up laboratory studies showed that fingers of Cavendish, and another commercial variety Lady-finger, are very poor hosts for B. musae, with very low host selection rates by female flies and very poor immature survival. An analysis of a recent (within last decade) incursion of B. musae into the Gazelle Peninsula of East New Britain Province, PNG, provided the final set of B. musae data. Surveys of the fly on the peninsular showed that establishment and spread of the fly in the novel environment was very rapid and thus the fly should be regarded as being of high biosecurity concern, at least in tropical areas. Supporting the earlier impact studies, however, banana fly has not become a significant banana fruit problem on the Gazelle, despite bananas being the primary starch staple of the region. The results of the research chapters are combined in the final Discussion in the form of a B. musae focused PRA for PNG banana fruit. Putting the thesis in a broader context, the Discussion also deals with the apparent discrepancy between high local abundance of banana fly and very low infestation rates. This discussion focuses on host utilisation patterns of specialist herbivores and suggests that local pest abundance, as determined by trapping or monitoring, need not be good surrogate for crop damage, despite this linkage being implicit in a number of international phytosanitary protocols.

Frugivorous insects, specialised herbivores that consume fruit and seeds, are considered detrimental to host plant fitness. Their direct link to genetic fitness via consumption of plant reproductive tissue, and their negative socioeconomic association with agriculture exacerbates their harmful status. However, empirical testing of insect frugivore effects on host plants, and ecological research on the contribution of insect frugivores to multitrophic frugivory systems, is lacking. In the current study, direct effects of a non-mutualistic, insect frugivore/host plant system were tested and results showed variable effects. Beneficial, detrimental, but predominantly neutral effects on germination and seed production were observed between the Queensland fruit fly (Bactrocera tryoni) and tomato and capsicum plants. Significant effects on seed production were unexpected because infestation occurs after seed set. It was also found that eggplant, although a recorded host of B. tryoni, is inconsistent in its ability to sustain B. tryoni larvae through to its final instar. These results confirmed a simplification and presumption associated with insect frugivore (specifically fruit fly)/host plant interactions. Larval movement, infestation-induced fruit decay, pulp removal and germination were then investigated. For all hosts (tomato, apple and paw paw), treatments infested by B. tryoni decayed significantly quicker and to a greater extent than uninfested treatments, with obvious but variable changes to the texture and appearance. The movement of B. tryoni larvae, pattern of infestation-induced decay and pulp removal was unique and host dependent for all hosts. Only seeds from infested tomato were shown to germinate during the experiment. This indicated that host fruit characteristics are responsible, in part, for variable direct effects on host plant fitness by insect frugivores. Variable direct effects between insect frugivores and host plants, combined with the more rapid decay of infested fruits is likely to have implications for seed dispersal and seed predation by a third trophic level. The characteristics of fruit that are changed by infestation by an insect frugivore were then tested for their effect on a vertebrate frugivore, to illustrate the importance of recognising multitrophic interactions and indirect effects in frugivory. Specifically, seed predating rodents were incorporated into the study and their response to infested and uninfested fruits were recorded, as well as their reaction to the changes in fruit caused by insect frugivores (i.e. texture, smell, larvae presence and sound). Apple and pear infested with B. tryoni larvae were found to attract rodents, while infested tomato and paw paw had a neutral effect on the native rats. This differed from the predominant finding in the literature, which was a deterrent effect on avian seed dispersers. Vertebrate response to fruit infested with insect frugivores therefore, is variable. Assessing the indirect effect of insect frugivores on host plant fitness by attracting or deterring another trophic level requires knowledge of the direct effect between the introduced trophic level and the host plant. For example, the attraction of a seed predator may be as detrimental to host plant fitness as the deterrence of a seed disperser. This illustrates the complexity associated with assessing insect frugivore effects on host plant fitness. Results also indicated that differences in pulp texture, caused by infestation, have a significant effect on rodent preference for infested or uninfested treatments. Pulp texture is likely to effect rodent foraging efficiency, whereas the presence of B. tryoni larvae was observed to be inconsequential to rodent response to fruits. For rodents, and indeed any trophic level motivated by foraging efficiency, this finding raises the issue that for long lived fruiting plants, outside factors such as food abundance and competition for food, may cause a variable response to fruits infested by insect frugivores. From these investigations it has become apparent that insect frugivores are not consistently harmful to host plant fitness, as suggested by their negative stigma, but are likely to contribute variable effects, directly and indirectly, on multiple components of plant fitness and multitrophic frugivory systems.

Frugivorous insects, specialised herbivores that consume fruit and seeds, are considered detrimental to host plant fitness. Their direct link to genetic fitness via consumption of plant reproductive tissue, and their negative socioeconomic association with agriculture exacerbates their harmful status. However, empirical testing of insect frugivore effects on host plants, and ecological research on the contribution of insect frugivores to multitrophic frugivory systems, is lacking. In the current study, direct effects of a non-mutualistic, insect frugivore/host plant system were tested and results showed variable effects. Beneficial, detrimental, but predominantly neutral effects on germination and seed production were observed between the Queensland fruit fly (Bactrocera tryoni) and tomato and capsicum plants. Significant effects on seed production were unexpected because infestation occurs after seed set. It was also found that eggplant, although a recorded host of B. tryoni, is inconsistent in its ability to sustain B. tryoni larvae through to its final instar. These results confirmed a simplification and presumption associated with insect frugivore (specifically fruit fly)/host plant interactions. Larval movement, infestation-induced fruit decay, pulp removal and germination were then investigated. For all hosts (tomato, apple and paw paw), treatments infested by B. tryoni decayed significantly quicker and to a greater extent than uninfested treatments, with obvious but variable changes to the texture and appearance. The movement of B. tryoni larvae, pattern of infestation-induced decay and pulp removal was unique and host dependent for all hosts. Only seeds from infested tomato were shown to germinate during the experiment. This indicated that host fruit characteristics are responsible, in part, for variable direct effects on host plant fitness by insect frugivores. Variable direct effects between insect frugivores and host plants, combined with the more rapid decay of infested fruits is likely to have implications for seed dispersal and seed predation by a third trophic level. The characteristics of fruit that are changed by infestation by an insect frugivore were then tested for their effect on a vertebrate frugivore, to illustrate the importance of recognising multitrophic interactions and indirect effects in frugivory. Specifically, seed predating rodents were incorporated into the study and their response to infested and uninfested fruits were recorded, as well as their reaction to the changes in fruit caused by insect frugivores (i.e. texture, smell, larvae presence and sound). Apple and pear infested with B. tryoni larvae were found to attract rodents, while infested tomato and paw paw had a neutral effect on the native rats. This differed from the predominant finding in the literature, which was a deterrent effect on avian seed dispersers. Vertebrate response to fruit infested with insect frugivores therefore, is variable. Assessing the indirect effect of insect frugivores on host plant fitness by attracting or deterring another trophic level requires knowledge of the direct effect between the introduced trophic level and the host plant. For example, the attraction of a seed predator may be as detrimental to host plant fitness as the deterrence of a seed disperser. This illustrates the complexity associated with assessing insect frugivore effects on host plant fitness. Results also indicated that differences in pulp texture, caused by infestation, have a significant effect on rodent preference for infested or uninfested treatments. Pulp texture is likely to effect rodent foraging efficiency, whereas the presence of B. tryoni larvae was observed to be inconsequential to rodent response to fruits. For rodents, and indeed any trophic level motivated by foraging efficiency, this finding raises the issue that for long lived fruiting plants, outside factors such as food abundance and competition for food, may cause a variable response to fruits infested by insect frugivores. From these investigations it has become apparent that insect frugivores are not consistently harmful to host plant fitness, as suggested by their negative stigma, but are likely to contribute variable effects, directly and indirectly, on multiple components of plant fitness and multitrophic frugivory systems.

Selective accumulation of certain metals (elements) to exceptionally high concentrations in plants is intriguing. Approximately 425 species of so-called metal hyperaccumulators are currently known, of which about 75% hyperaccumulate nickel. Stackhousia tryonii Bailey (Stackhousiaceae) - a rare, herbaceous, serpentine-endelnic species - is one of the three nickel hyperaccumulators reported from Australia. This thesis reports research aimed at two broad aspects: propagation and ecophysiology of Ni hyperaccumulation in S. tryonii. Protocols were developed for seed germination, vegetative propagation and micropropagation and with the view to producing sufficient plants for use in the current study. Four-year-old S. tryonii seeds had poor germination (< 25%). However, this species was relatively easy to propagate via stem cuttings and micropropagation methods, as it possessed very high regenerative capacity (one explant produced up to 18 shoots within 4 weeks). Micropropagated shoots also responded well to ex vitro rooting, and were successfully hardened under controlled conditions. These propagation protocols could be useful to underpin conservation programs and mine site revegetation. The examination of natural populations of S. tryonii for arbuscular mycorrhizal colonisation suggested that S. tryonii is a favourable host. A moderately high colonisation (29-39%) of roots by arbuscular mycorrhizal fungi suggested a possible role of these fungi in improved nutrition of S. tryonii in typically nutrient-poor serpentine soils. A positive relationship between root colonisation and leaf Ni concentration suggested that mycorrhizal fungi might be involved in increased influx of Ni into the roots, which is readily transported and localised in the tissues. Spore density was very low (3-4 spores 100 g-¹dry soil, for two depths) in the associated serpentine soils and the dominant mycorrhizal species were: Glomus albidum, aggregatum, G. intraradices and G. tenebrosum. Based on five key soil characteristics (viz. pH, Ca, Mg, Ni and P), the study sites were segregated into four groups using hierarchical cluster analysis. Considerable variation existed in tissue Ni (and other elements) concentrations, both within and between populations and followed the order: leaf> root> stem. Localisation and spatial distribution of nickel, within both vegetative (leaf and stem) and reproductive (fruit) tissues were investigated using two microanalytical techniques [viz., micro-proton-induced x-ray emission spectrometry (micro-PIXE; nuclear microprobe) and scanning electron microscope with energy-dispersive x-ray spectroscopy (SEM-EDXS)]. In leaf and stem tissues, Ni was localised within epidermal and sub-epidermal tissues, palisade/mesophyll tissues, vascular bundles and/or pith. In contrast, in fruits, this metal was partitioned to the fruit wall (pericarp), while endospermic and cotyledonary tissues contained very little Ni. Accumulation of higher levels of Ni within the pericarp does not appear to inhibit seed germination in S. tryonii. To elucidate physiological mechanisms o fNi detoxification in S. tryonii, organic acids (leaf tissue) and free amino acids (xylem sap) were quantified using HPLC. Nickel concentration in the leaf tissues increased from 3695 g g-¹to 13,717 g g-¹with soil nickel supplementation, of which > 60% was extracted with dilute acid (0.025 M HCI). Oxalic, citric and malic acids were detected and quantified in the leaf tissue. Malic acid was the dominant organic acid, and based on a Ni to malic acid ratio (between 0.2:1 and 1:1), malic acid appears to play a major role in detoxification/transport and storage of Ni in S. tryonii. The total amino acid concentrations in the xylem sap decreased with nickel treatment. Glutamine was the major amino acid in both the low- and high- nickel treated plants. A role of amino acids in nickel complexation and transport in S. tryonii could not be established. The possibility of hyperaccumulated Ni acting as an osmoticum under waterstress (drought) in serpentine soils was also investigated. Drought severely affected the growth and overall biomass of the plants. However, survival of plants at the lowest levels of soil moisture (i. e. 20% of field capacity) suggested that it possesses an efficient water regulation mechanism. The results indicated possible involvement of Ni in osmotic adjustment under drought stress.

碩士
國立師範大學
生物學研究所
83
Sphaeropteris lepifera (Hook.) Tryon is one of the species of tree ferns distributed along the islands arch in eastern Asia, such as Taiwan, Ryukyu archipelago and the Philippines. Taiwan located in the center of the island arch, it is naturally worthy of studying the genetic structure of this fern. The major destination of this study is to assess the pattern of genetic variation in subpopulations of tree fern Sphaeropteris lepifera (Hook.) Tryon in Taiwan. Eighteen subpopulations were surveyed by using starch gel electrophoresis methods. Sixteen loci of 13 isozymes were detected. The mean expected herterozygosity(HE) was 0.057 and ranged from 0.05 to 0.063. The mean observed heterozygosity(HO) was 0.064 and ranged from 0.035 to 0.082. The total heterozygosity(HT) was 0.064 and ranged from 0.02 to 0.108. The percentage of polymorphic loci(P) was 12.5 for polymorphism. On average, the number of alleles per locus (AP) was 1.1 and the effective number of alleles per locus(AE) was 1.07. F-statistics revealed that the inbreeding coefficient within subpopulations(FIS) was -0.157. This negative value suggest that the species preferred intergametophytic outcrossing. The level of genetic differentiation among subpopulations(FST) was 0.039. It showed that the level of genetic differentiation among subpopulations was very low. Gene flow rate among subpopulations was far greater than one (Nm=6.16) and genetic distance is very small ranged from 0 to 0.015, moreover, genetic distance between subpopulations did not correlate to the geographical distance. All these results indicated a lack of barriers to gene flow among subpopulations, thus there is no genetic differentiation among subpopulations of Sphaeropteris lepifera (Hook.) Tryon in Taiwan.