Genetically modified (GM) crops were introduced in South Africa in 1989 and commercially available by 1998. Legislation to control the use of GM crops was only implemented in 1999, with the genetically modified organisms (GMO) act (15 of 1999). In 2012 2.9 million ha of GM crops were planted in South Africa alone. GM Crops, such as Bt maize, are promoted as safer for the environment since no chemical pesticides are needed. However, recently GM crops have been making headlines as more and more studies find adverse effects of these crops on non-target organisms. The effects on aquatic environments have not yet been fully determined, even though traces of Bt residue have been found in water systems surrounding agricultural lands. The aim of this study was to establish the effects of the Bt toxin on fecundity, development and growth of Bulinus tropicus, a freshwater snail. The experiment made use of a static renewal tests to expose B. tropicus to 50 cm2 Bt maize and cotton leaves in 900 ml of synthetic freshwater. The snails were exposed for the duration of one full life cycle (embryo to adult). Endpoints measured included the development, growth, fecundity, and deformities of the reproductive organs. The results obtained showed retarded development and low embryo survival when the snails were exposed to cotton leaves, irrespective of the presence or absence of Bt, indicating to the possibility of trace residues of chemical pesticides may have been present on the leaves. Initial stimulated growth of hatchlings was observed for both Bt cotton and maize exposures, but after sexual maturity has been reached, ‘surplus’ energy was probably shared between growth and fecundity, resulting in a reduction of growth rate. Energy is gained from their diet, thus a sub-optimal diet would result in less energy available to functions such as growth and fecundity. Signs of developmental instability were found in the formation of the shell opening of the snails exposed to Bt. Fecundity decreased significantly after snails had been exposed to Bt maize / cotton leaves. No differences were found in the penis sheath-preputium length ratio, indicating that Bt had no deleterious effects on the reproductive organs. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014

The mosquito Aedes aegypti is responsible for 50 million dengue fever infections in humans each year. A novel control strategy, named RIDL (Release of Insects carrying a Dominant Lethal) relies on releasing large numbers of genetically sterile male insects in order to control pest populations. This thesis describes the development of new tools to improve the efficiency of RIDL against Ae. aegypti and assessment of candidate strains for field release. <strong>Chapter 3</strong> describes a new selection system for Ae. aegypti based on ethanol susceptibility conferred by the alcohol dehydrogenase gene (Adh) from Drosophila melanogaster. I observed that the susceptibility of Ae. aegypti larvae to ethanol can be triggered by expression of Adh in larvae. <strong>Chapters 4</strong> and <strong>5</strong> focus on RIDL strains with a genetic sexing mechanism, for easy and stringent selection for males before mass-releases, eliminating disease- transmitting females. In <strong>Chapter 4</strong>, I describe the creation of a late-acting sexing strain of Ae. aegypti based on the Ae. aegypti doublesex (Aedsx) alternative splicing system. In <strong>Chapter 5</strong>, I describe an attempt to create an early-acting sexing system. Killing the females of the release generation early would free space and resources for the production of males. This was done by combining the Adh gene and the Aedsx alternative splicing system described in <strong>Chapters 3</strong> and <strong>4</strong>. <strong>Chapter 6</strong> reports the results of a comparison, in terms of quality and productivity, between an existing Ae. aegypti RIDL strain and a wild-type control. Results showed equivalent female quality and productivity between the two strains, while RIDL males were less fertile in comparison with wild-type males. RIDL eggs also seemed more susceptible to long- term storage. The results of this work show promise for development of novel RIDL strains that may be used in the field to control disease-transmitting mosquitoes.

Saxicolous lichens on exposed bedrock are subjected to desiccation stress and intense light levels. Members of the genera Xanthoparmelia and Arctoparmelia are common foliose lichens on the Precambrian Shield, produce abundant sexual structures, and form part of the bedrock communities. The general goal of this thesis was to better understand the influence of community and underlying geology on three saxicolous lichens: Arctoparmelia centrifuga, Xanthoparmelia viriduloumbrina and X. cumberlandia. More specific goals were further examined in five chapters to investigate: 1) life history strategies of the three species, 2) a trade-off between fecundity and fungal secondary metabolite production; 3) an effect of substratum element composition on previously defined communities and lichen biology, 4) substratum preferences of Xanthoparmelia species, and 5) the photobiont guild hypothesis of the three species in a preliminary study. Field collections of lichens and environmental data were made in four locations on the Precambrian Shield in Manitoba and Ontario. Secondary metabolites were determined by digitally enhanced thin-layer chromatography. Fecundity was measured by number of apothecia, ascospores, and percent germination. Elements in rock samples were quantified by aqua-regia digest and inductively coupled plasma optical emission spectroscopy analysis and light microscopy was used to observe and quantify fungal germination and growth. The results showed eighty-one lichen species comprising three lichen communities; mossy rock, grassy rock, and treed rock communities. Lichen communities and fecundity were used to characterize life history strategies as competitive for Arctoparmelia centrifuga, stress tolerant for Xanthoparmelia viriduloumbrina, and ruderal generalist for Xanthoparmelia cumberlandia. A potential trade-off was reported for X. cumberlandia between sexual fecundity and a secondary metabolite. Substratum preferences were found at the genus level and element differences at the species level. Experimental evidence further supported geological preferences for the three species. Finally, the photobiont guild hypothesis could not be supported by this preliminary work. This research provides a broad overview of ecological and biological patterns found in Arctoparmelia and Xanthoparmelia species. The research forms a foundation for further studies in substratum preference and life history characterization in lichens. It can be further applied to habitat suitability modelling which may be valuable for phylogenetic context or in conservation biology of lichens. / October 2015

Ações antrópicas, como a construção de reservatórios, alteraram a migração de peixes que afeta a função normal do eixo hipotalamo-hipófise-gônadas. Para atenuar o impacto ambiental sobre a biota, existem programas de repovoamento com objetivo de reproduzir as espécies de peixes atingidas pelas barragens. Na piscicultura de Ponte Nova, na Bacia do Alto Tietê, o peixe migratório Astyanax fasciatus é rotineiramente produzido para o repovoamento com protocolos de reprodução artificial convencionais, mas o seu sucesso varia entre as fêmeas. Um estudo de citogenética detectou que o número de cromossomos foi diferente entre os reprodutores, uma característica comum em A. fasciatus. O objetivo do presente estudo foi estudar a fisiologia reprodutiva de Astyanax fasciatus com diferentes números de cromossomos, em ambiente natural (AN) e em cativeiro (Cat) e as possíveis alterações que possam explicar diferentes resultados de resposta à reprodução induzida em cativeiro. Fêmeas adultas de cada grupo experimental (G1-46 cromossomos; com baixa resposta à reprodução induzida; e G2 - 48 cromossomos; com boa resposta à reprodução induzida) foram coletadas em Cat e em AN ao longo de um ano. Amostras de sangue foram retiradas para análise plasmática de estradiol (E2), e os ovários para o cálculo da fecundidade relativa (FR), diâmetro oocitários, Índice Gonadossomático (IGS) e análises histológicas para identificação do estágio de maturação. As fêmeas do G1 nos dois ambientes iniciaram a fase vitelogênica do ciclo reprodutivo no inverno com o aumento da concentração de E2 plasmático. Nas fêmeas de AN, neste mesmo grupo, a maior porcentagem de oócitos vitelogênicos foi mantida nos ovários desde a primavera até o verão, período no qual a concentração de E2 continuou elevada no plasma. Por outro lado, no Cat, as concentrações de E2 não se mantiveram elevadas nas demais estações do ano, limitando-se apenas ao pico do inverno. Mesmo assim, as fêmeas confinadas mantiveram a FR significativamente mais elevada quando comparadas àquelas de AN, assim como maiores porcentagens de oócitos vitelogênicos, evidenciando a ausência de desova e lentidão no processo de reabsorção do vitelo. Já as fêmeas do G2, em AN iniciaram a fase vitelogênica do seu ciclo reprodutivo no outono, com o aumento progressivo dos níveis de E2 que atingiram seu pico na primavera, com a desova ocorrendo no verão. Por outro lado, a permanência no Cat, de alguma forma, alterou a sensibilidade às dicas ambientais do ciclo sazonal, e os níveis de E2 e a FR se mantiveram altos praticamente o ano todo. Estes dados sugerem que A. fasciatus com números diferentes de cromossomos têm padrões reprodutivos diferentes tanto em Cat como em AN e que em cativeiro fêmeas do G1 terão maior sucesso na indução quando manipuladas logo após o inverno, já fêmeas do G2 em Cat parecem ter sucesso na indução praticamente o ano todo / Anthropic actions, such as the construction of reservoirs, alter fish migration affecting the normal function of the brain-pituitary-gonads axis. To mitigate the environmental impact on the biota, fish restocking programs aim to reproduce fish species affected by dams. In the Ponte Nova Fish Farm, in the Upper Tietê River Basin, the migratory fish Astyanax fasciatus is routinely produced for restocking with a conventional artificial breeding protocol, but its success varies among the females. A cytogenetic study detected that the number of chromosomes was different among the broodstocks, a common feature in A. fasciatus. The purpose of this study was to study the reproductive physiology of Astyanax fasciatus with different numbers of chromosomes in a natural environment (AN) and captivity (Cat) and the possible changes that might explain different results in the success of induced reproduction in captivity. Adult females of each experimental group (G1-46 chromosomes; with low response to induced reproduction, and G2 - 48 chromosomes, with good response to induced reproduction) were collected in Cat and AN over one year. Blood samples were taken to analyze plasma estradiol (E2), and samples of ovaries to calculate the relative fecundity (FR), oocyte diameter, gonadosomatic index (GSI) and histological analyzes to identify the maturation stage. Females of G1, in both environments, started the vitellogenic phase of the reproductive cycle in the winter, with an increase in E2 levels. In the wild animals, the highest percentage of vitellogenic oocytes was maintained in the ovaries from spring to summer, a period in which E2 levels remained high. On the other hand, in captivity, a higher level of E2 was observed only in winter. Even so, the females in captivity maintained the fecundity significantly higher when compared with the wild ones, and also a higher percentage of vitellogenic oocytes, evidencing the absence of spawning and a delay in the yolk absorption. In G2, the vitellogenic stage of oocytes in wild females started in the fall, with a progressive increase in E2 levels, reaching its peak in spring, with the spawning in summer. On the other hand, remaining in the captivity, somehow altered the availability to the environmental tips of the seasonal cycle, and E2 levels as well as the FR virtually remained high throughout the year. These data suggest that A. fasciatus with different numbers of chromosomes have different reproductive patterns, both in a Cat and AN. G1 females could succeed in induced reproduction when handled immediately after winter, while G2 females seem to succeed the artificial reproductive induction throughout the year

Este trabalho teve como objetivo verificar a estratégia reprodutiva de seis lepidópterospraga, os noctuídeos Anticarsia gemmatalis, Heliothis virescens e Spodoptera frugiperda (Noctuidae), Diatraea saccharalis (Crambidae), Gymnandrosoma aurantianum (Família) e Stenoma catennifer (Elachistidae), tendo como alvo principal o uso de recursos nutricionais na fase adulta para sustentar o processo de reprodução e o efeito da atividade de cópula e temperatura na reprodução dessas espécies. Apesar de todas as espécies apresentarem índice de ovigenia bem inferior a 1, indicando a maturação de oócitos no decorrer da vida adulta, apenas A. gemmatalis e H. virescens necessitaram de alimentação na fase adulta para sustentar o processo reprodutivo, enquanto as demais espécies se utilizam dos nutrientes armazenados durante a fase larval. A partir destes resultados, foram escolhidas duas espécies que apresentavam estratégias reprodutivas distintas. Uma que utilizava apenas os nutrientes armazenados na fase imatura, S. frugiperda, enquanto a outra necessitava adquirir nutrientes na fase adulta para a sua reprodução, A. gemmatalis, para se verificar o efeito da freqüência de cópula e de seus efeitos na fecundidade, fertilidade e longevidade de adultos com estratégias reprodutivas distintas. A freqüência de cópula afetou de forma semelhante a longevidade de ambas espécies, havendo redução na longevidade com o aumento no número de cópulas. Porém, a fecundidade de S. frugiperda mostrou correlação positiva com a freqüência de cópula, não sendo verificado nenhum efeito na fecundidade de A. gemmatalis. Machos de ambas as espécies podem contribuir de forma semelhante para a reprodução da fêmea, independentemente de sua experiência prévia. Assim, a reprodução de fêmeas que copularam com machos experientes (2 cópulas prévias) foi similar àquela de fêmeas acasaladas com machos virgens. No entanto, a duração da cópula aumentou com a experiência do macho, sendo a terceira cópula mais longa do que a primeira. A relação da temperatura (15, 20, 25, 30 e 35ºC) e freqüência de cópula também foi investigada para essas espécies, sendo observado que as temperaturas extremas (15 e 35oC) afetaram a freqüência de cópula de ambas espécies. Porém, a temperatura demonstrou afetar as interações entre o número de cópulas e demais atributos biológicos relacionados à reprodução apenas para S. frugiperda mantidas a 25ºC, onde o aumento no número de cópulas resultou em maior fecundidade. / This paper deals with the reproductive strategies of six lepidopteran species, considering the use of food sources in the adult stage and the effect of mating activity and temperature in the reproduction of those species. The lepidopteran species were: Anticarsia gemmatalis, Heliothis virescens, Spodoptera frugiperda (Noctuidae), Diatraea saccharalis (Crambidae), Gymnandrosoma aurantianum (Tortricidae), and Stenoma catenifer (Elachistidae). From this group two species with different reproductive strategies were selected: S.frugiperda, which uses the nutrients stored during the larval stage, and A.gemmatalis, which uses nutrients acquired in the adult stage. Then one verified the mating frequency and its effects on adult fecundity, fertility and longevity. For both species longevity decreased as the number of matings increased. Female reproduction was similar either when they mated with virgin males or non virgin males. However mating duration was different for the third mating was longer than the first one. The temperatures of 15º and 35ºC did affect the mating frequency of both species. The frequency of matings was positively related to fecundity but only for S.frugiperda. Also S.frugiperda at 25ºC presented higher fecundity with the increasing in the number of matings.

Understanding how organisms function is central to Biology. Assessing how animals respond to fluctuations in their environment and determining inter-individual variation in phenotypic plasticity is paramount to identifying the physiology of traits, the selective pressures which have shaped them, and how we can manipulate them to benefit human life. The over-arching goal of my thesis is to understand the effects of sex, diet and pathogen exposure on the physiology of the fruit fly to assess the versatility of their individual traits in response to these natural factors. Chapter 2 investigates how the sexes utilise nutrition towards their lifespan and reproduction, providing evidence that the reproduction of males and females requires different dietary components while lifespan does not. Chapter 3 reveals that the sexes also differ in how they utilise nutrients for pathogen resistance identifying that females are highly protein-limited and more susceptible to infection than males. Chapter 4 provides the first comprehensive study of how organisms alter their dietary intake in response to infection, finding that flies behaviourally ingest less and consume higher protein:carbohydrate ratio diets when exposed to live fungal spores. Chapter 5 explores the phenomenon of trait-enhnacing external stresses, a response often termed hormesis. This study reveals that the beneficial physiological response from inactive fungal spore exposure, a potential form of hormesis, incurs immune costs. The implications of my results to the field of physiology are discussed in Chapter 6 where I also highlight the limitations of my work and potential consequences for life history research. Overall it is determined that studies investigating the natural physiological response of organisms or potentially beneficial treatments for our own species, must consider sex-specific effects, physiological consequences in a variety of traits, and how organisms may utilise variation within their environment to alter their phenotypic condition.

Biodiversity, ecosystems, industry and human health are threatened by invasive plant species. The costs of mitigating damages run into billions of pounds per annum. Fundamental to the control of invasive plant species is an ability to predict which species will become invasive. Yet identification of predictive differences between invasive and non-invasive species has proven difficult to pinpoint. In this thesis I identify several weaknesses within published literature, and using field experiments and meta-analyses we address these to find consistent predictors of invasiveness amongst plants. Specifically, I recognize that predictors of invasiveness can be identified by studying plant species in the native range because species may undergo phenotypic and demographic changes following naturalization (Chapters 2 – 5). I also recognize the importance of comparing globally invasive and non-invasive species, and the importance of accounting for phylogenetic relationships so as not to inflate or conceal differences (Chapters 2 – 4). Finally, I investigate whether particular analyses are more appropriate for investigating life history and demographic differences (Chapter 5). This thesis comprises an introductory chapter (Chapter 1), four data chapters (Chapters 2 - 5) and a general discussion (Chapter 6). Chapters 2 and 3 compare life history traits of plant species known to be invasive elsewhere, with their exported but non-invasive sympatric relatives in the native range. Chapter 4 utilizes Population Projection Matrices held within the COMPADRE Plant Matrix Database, to compare demographic projections of stable and transient dynamics of invasive and non-invasive plants; and Chapter 5 compares ten metrics, derived from Population Projection Matrices, of seven invasive species between the native and invaded range to determine if there are demographic or life history differences that facilitate invasion, and to identify those analyses that are most likely to reveal such differences. I find reproductive capacity to be a predictor of invasiveness, and that analyses of transient dynamics are more likely than analyses of projected stable dynamics to reveal demographic or life history differences between invasive and non-invasive species or populations of plants. I discuss these findings in the context of invasive risk assessment protocols and highlight future research opportunities.

Sexual selection was defined by Darwin in 1871 as selection acting solely on reproduction success. It is known to act on males resulting in extravagant ornamentations or other attributes, but in recent years more studies have shown that sexual selection also act on females. There is empirical evidence in several taxa that the secondary sexual ornament also acts as a measurement on the females’ reproductive quality, it is an honest trait. In Gallus gallus the comb has been found to be an honest ornament. Quantitative Trait Loci have been found on chromosome 1 and 3 for comb- and egg size. The honesty of the comb is hypothesized to be caused by either a pleiotropic effect gene linkage. In this study an 8th generation Advanced Interline Cross was used to guarantee maximum recombination of alleles to observe phenotypic effects. 177 females were detained during 4 weeks to measure fecundity. Egg number, mean egg weight and total egg size were correlated to comb size: length, area and weight. Correlation between comb size and total egg weight were found to be negative, suggesting the comb to be a dishonest signal. The phenotypic measurements observed in this study suggest that the genes for egg production and comb size are linked, and this linkage has been broken in the F8 analysed in this study.

In this study, I describe the seasonality of reproduction in bottlenose dolphins by examining data from stranded animals, photographic surveys and focal follows. I examined inter-birth intervals from focal follows of known female dolphins. I found bottlenose dolphins that frequent the coastal waters of North Carolina to be comprised of at least two populations; one with a primarily spring birthing peak and a presumed second (or second and third) with two smaller birthing peaks in the fall and winter. These animals are reproducing at 2-3 year inter-birth intervals, which are shorter than bottlenose dolphin inter-birth intervals in the Moray Firth, Scotland, Shark Bay, Australia, or Sarasota Bay, FL. A decrease in reproductive intervals can indicate a density-dependent response to an anthropogenic disturbance or a natural change. Association patterns between and among these known females revealed relationships that have persisted for more than a decade. Most association patterns of the female dolphins in this area are long-term casual acquaintances which are evident in the fission-fusion grouping pattern, and individuals are not highly gregarious. Females appear to associate with most other females in the local area and do not form bands, as defined by researchers in Sarasota, FL (Wells et al. 1987). However, females do exhibit preferred associates, with whom they associate, regardless of reproductive state. Associations of females with young of the year were slightly stronger than associations between females with different aged calves, except for preferred associates. Future work will include genetic research on some of these known females, and continued study of the life and reproductive histories of these known females and their offspring. / Dissertation

<p>This dissertation investigated spawning biology of female blue crabs, <italic>Callinectes sapidus</italic>. Females mate following the terminal molt and undertake a spawning migration seaward, producing multiple clutches of larvae. To examine lifetime reproductive potential of female crabs, individual crabs were confined in the field from terminal molt to death. Crabs produced up to 7 clutches over 1-2 spawning seasons and survived up to 394 d after the terminal molt. Time to first clutch and time between clutches were positively correlated with carapace width and best described by degree-days. Size at maturity was negatively correlated with water temperature on the day of the terminal molt. Most measurements of clutch quality and larval fitness were similar for all clutches. The percentage of embryos developing normally decreased 40% from clutch 1 to clutch 4 and clutch volume decreased 50% from clutch 1 to clutch 5. Thus, most of a crab's reproductive output is from the first few clutches. </p><p>Using swimming and abdominal pumping assays, the roles of pheromones in larval release and migratory behavior were investigated. Following delivery of egg extract, bradykinin (a pheromone mimic), and trypsin (an enzyme that generates peptide pheromones), ovigerous crabs responded with increased abdominal pumping, indicating that peptide pheromones stimulate larval release in blue crabs. Ovigerous crabs responded with increased swimming following delivery of egg extract, but not following delivery of a peptide pheromone mimic or an enzyme that produces peptide pheromones. These results suggest that some substance generated from the egg mass stimulates vertical swimming, but that peptides alone do not stimulate swimming. A blend of molecules, possibly including sugars, may be the cue that stimulates swimming behavior. </p><p>Endogenous rhythms in vertical swimming, a mechanism underlying migration in tidal estuaries, were examined in the laboratory under constant conditions in juvenile females, recently-molted females, and females with mature ovaries from Beaufort, NC. Rhythms were variable in each stage, though circatidal rhythms consistent with ebb tide transport were observed in juvenile females and recently-molted females. Crabs with mature ovaries typically swam around the time of high tide. Rhythms were also examined for ovigerous females collected from estuaries with three different tidal regimes: semi-diurnal, diurnal, and non-tidal. Crabs from the tidal estuaries had circatidal or circalunidian swimming rhythms with period lengths corresponding to the tidal period of their home estuary. Swimming occurred primarily on ebb tide. Crabs from the non-tidal estuary had a circadian rhythm of vertical swimming around the time of sunset. Such a rhythm has no obvious migratory significance and migration likely takes place though another mechanism.</p><p>Swimming behavior was also examined in the field in one non-tidal site and three tidal sites. Crabs were tethered in the field and swimming was monitored using archival pressure tags. Crabs tethered in the non-tidal site did not swim, possibly due to the lack of necessary environmental cues. Crabs at the tidal sites swam primarily on ebb tides. Swimming was greatest at the deepest site, which also had the strongest currents. This site is known to be a migratory area for spawning blue crabs. Decreased swimming behavior was observed at the two shallower sites, including one site that is known to be habitat for all stages of blue crabs. These results indicate that swimming behavior is variable among different areas in a single estuary. In areas where swimming is reduced, crabs may continue migrating seaward by walking or may spend additional time in that area to forage. Within each site, peak swimming generally occurred during the time of the most rapid decrease in water level, suggesting that hydrostatic pressure may serve as a cue for swimming. </p><p>Mark-recapture studies were conducted in three rivers (North River, South River, Adams Creek) in eastern North Carolina, and recently-molted female crabs were tagged to ensure a relatively constant time since molting. Most crabs traveled relatively short distances and were recaptured before producing a clutch of eggs. Individuals that moved substantial distances typically moved down-estuary. The Adams Creek canal, connecting Adams Creek with the Newport River estuary, functioned as a migratory corridor, as crabs from both Adams Creek and South River migrated down the canal, presumably using ebb tide transport. Many of the crabs that migrated down the canal into the Newport River were recaptured while ovigerous. Results of this study support the hypothesis that rapid long-distance migratory movements do not begin until production of the first clutch of eggs, though some down-estuary movement takes place by prior to production of the first clutch of eggs.</p><p>Female blue crabs mate following the terminal molt and begin moving seaward soon thereafter by walking and swimming. Once the appropriate salinity (> 22 ppt) is reached, the first clutch of eggs is produced and migration rate rapidly increases. Blue crab spawning biology should be similar throughout the range of the species. After taking latitudinal temperature variation and other local variables into account, results presented here should be applicable not only to blue crabs in North Carolina, but in other areas as well.</p> / Dissertation