Thesis (Ph.D.) - University of St Andrews, March 2009.

Populations of guppies living in different streams vary in their "behaviour and morphology. Some populations live in fast-flowing streams while others occupy slow-flowing water. I hypothesized that behavioural differences between the populations may represent adaptations to stream velocity. I tested seven predictions based on this hypothesis in two experiments. In Experiment I, I. examined the behaviour of laboratory reared guppies descendant from three natural populations. These guppies were examined at .03, .07, .10, and .20 m/sec stream velocities. Experiment II used wild-caught guppies from four populations. Their courtship behaviour was examined in still water (.00 m/sec) and at .08 m/sec velocity. As predicted, in Experiment I guppies from slow-flowing water showed l) greater cohesion, 2) less aggressive behaviour, and 3) a greater preference for the surface region of stream tanks than fast water fish. Also as predicted, slow water males performed fewer sigmoid displays "but more thrusts and gonopodial swings than fast water guppies. The persistence of these behavioural differences in laboratory raised descendants of isolated populations demonstrates a genetic contribution to the differences. Therefore the differences are presumably the product of natural selection and represent evolutionary adaptations. Experiment I also showed that stream velocity directly affects the performance of courtship behaviour by males. The frequency of sigmoid displays and gonopodial swings decreased markedly as stream velocity increased. As stream velocity increased, fast water males maintained their frequency and duration of sigmoid displays better than slow water males, thus providing evidence for "behavioural adaptation to stream velocity. The higher ratio of sigmoid displays : thrusts exhibited by fast water fish may also represent an adaptation to stream velocity. Stream velocity had no direct effect on group cohesion and aggression in the guppy. However, it directly affected guppy stream depth preference. Slow water fish could not maintain position at the top of the stream in faster-flowing water, whereas fish bred from an intermediate stream velocity population were able to do so. Fast water fish always preferred the bottom of the stream bed. In Experiment II wild-caught fish from fast and slow-flowing streams were tested together in two stream conditions. Again, as predicted, slow water fish performed fewer sigmoid displays but more thrusts and gonopodial swings than fast water fish. Because of the slow velocity used during the experiment, no effect of a fast stream velocity on courtship behaviour was obtained. During the experiment males generally preferred to court females from their own population. These preferences may represent partial isolating mechanisms. I concluded that differences between guppy populations in courtship behaviour and stream depth preference represent adaptations to different stream velocities. Stream velocity is therefore presumed to have been one of several environmental factors that interacted to shape the guppy's present behaviour. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

Thesis (M.Sc.) - Carleton University, 2008. / Includes bibliographical references (p. 90-99). Also available in electronic format on the Internet.

No description available.

Effects of oxazepam concerning on social behavior in guppies are still unknown. The purpose ofthis thesis is to investigate if the benzodiazepine oxazepam has effects on fish behavior in terms ofsocial preferences and responses to predation risk using an olfactory cue mixture. After anexposure period of 15 days to 100 μg/l of oxazepam, behavioral experiments were performed overtwo days. Results indicate that oxazepam exposed fish were more social at the beginning of theexperiment, which differ from what was expected and from previous social preferences studies.Moreover, less social behavior was found as a result of combining oxazepam treatment andolfactory cue mixture (predator cues and guppy skin extract) treatment.

This thesis focuses on the guppy, Poecilia reticulata, as an invasive species. Its non-native distribution, the biology behind its success and the reasons for its introduction are examined. A worldwide email survey revealed that the guppy is established in at least 73 countries outside of its native range and that mosquito control schemes and the release of unwanted aquarium fish are the two primary routes of introduction. Knowledge gaps were identified; primarily the scarcity of scientific evidence for negative impacts of guppy introductions and similarly for mosquito control efficacy. Replicated mesocosm experiments demonstrated that female guppies are capable of routinely establishing populations, and that these retain behavioural viability over several generations. The first mesocosm study suggested that founders with very different evolutionary histories were equally good at establishing populations. The second mesocosm study suggested that monandrous females were extremely successful at establishing behaviourally viable populations, with no decline in behavioural variation. The effectiveness of guppies as mosquito control agents was examined in two related foraging experiments. The first study found little evidence for the presence of ‘prey switching’ in guppies, questioning the validity of previous work advocating their introduction to stabilise prey populations. The second study revealed a preference for non-vector mosquito larvae in a two-prey system. However, both mosquito species were consumed equally readily when habitat complexity increased. The presence of conspecifics affected female foraging behaviour. The presence of males reduced the strength of prey preference in the first study, and the presence of conspecifics of either sex removed prey preference in the second. Both demonstrate that multi-prey systems have important implications for the efficacy of poeciliids in biological control. Despite severe demographic bottlenecks, their adaptability and ability to rapidly increase in numbers enable guppies to establish and persist when introduced. Such bottlenecks are typical of introduction scenarios, warning that particular caution should be exerted when introducing this species, or other livebearing fish, to natural water bodies.

Orientador: Percilia Cardoso Giaquinto / Ana Carolina Kiss / Marisa Fernandes de Castilho / Thiago Lopes Rocha / Resumo: A população humana cresce em proporções maiores que a produção de alimentos. Nesse cenário, a agricultura potencializa este cultivo por meio do uso de defensivos agrícolas, como por exemplo, herbicidas à base de glifosato (HBG). Entretanto, tais produtos possuem vários efeitos adversos em organismos não-alvos, como peixes. Estudos apontam danos em tecidos e em material genético de peixes, porém, não há estudos sobre o comportamento reprodutivo dessa espécie quando expostas a concentrações permitidas por lei. Assim, testamos os efeitos de HBG na seleção sexual de parceiros e na qualidade espermática de machos de Poecilia reticulata. Para isso, avaliamos o comportamento sexual, o interesse sexual, a qualidade espermática e a receptividade das fêmeas a machos expostos a 2 concentrações de HBG (50 e 100 μg/L) por 48 horas. Para avaliar a escolha de parceiros, utilizamos o método de escolhas dicotômicas e análise de múltiplas escolhas. Já para análise da qualidade espermática, avaliamos a morfologia, a viabilidade, a concentração e a motilidade dos espermatozoides. Nossos resultados indicam que machos não expostos ao HBG diminuem a exibição para fêmeas expostas ao HBG e evitam copular com fêmeas expostas à concentração de 100μg/L. Além disso, fêmeas expostas ao HBG são menos receptivas à cópula. O HBG afetou a morfologia dos espermatozoides, onde machos expostos a 50μg/L apresentaram maior quantidade de células com danos primários. Porém, não afetou a viabilidade, concentração e m... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Human population grows in bigger proportions then food production worldwide. To solve this problem, increase food production is required. Agriculture has potentialized food production through pesticides usage. Besides that, GMO's increase production and usage of glyphosate based herbicide (HBG), since this product does not affect GMO's. HBG's have many side effects on non-target animals, such as fishes. Many studies demonstrated damage in a lot of tissues and DNA. However, effects on behavior and even in concentrations allowed by law have not been studies. We aim to assess the effects of a GHB on physiological and behavioral reproductive features of Poecilia reticulata as male sexual behavior, sexual interest, sperm quality and female receptivity. We used dichotomous and multiple-choice arenas for mate choice and viability, concentration, motility and morphology to assess sperm quality. HBG decrease female receptivity, affects male interest on perform displays and mate attempt with females exposed to 100µg/L. HBG also affected sperm quality of males exposed to 50µg/L concentration. Despite this, we did not find any effect on viability, concentration and motility of sperm cells of exposed males to any concentration. We conclude that HBG affects female receptivity, and, in turn, it affects sexual male effort, reducing display and mate attempt rate. Our data shows that HBG, even in environment relevant concentrations, can affect reproductive behavior and sperm quality. We show h... (Complete abstract click electronic access below) / Doutor

No description available.

Two processes may lead to genetic divergence among populations. One is mediated by geography, whereby physical barriers and geographic distance limit gene flow among populations, resulting in divergence due to drift or mutation. Another is ecological speciation, whereby populations adapt to their local environments via natural selection, and gene flow is impeded by selection against dispersers in favor of adapted residents. I used natural populations of guppies (Poecilia reticulata) to determine the relative influence of these two processes in the structuring of populations. If geography is playing a strong role, I predicted that gene flow would be greatly impeded by physical barriers and geographic distance. If ecology is playing a strong role, I predicted that gene flow would decrease with increasing strength of divergent selection among populations. Specifically, I examined the relative roles of physical barriers, geographic distance, predation, and various other habitat features (e.g. canopy cover, water velocity) on the amount of gene flow among populations. I was thus able to determine whether natural selection or decreased dispersal plays a greater role in the reduction of gene flow. I found that physical barriers and geographic distance played a large role in the regulation of gene flow among populations. Predation and physical habitat features did not play a role in the reduction of gene flow. My research clarifies the mechanisms involved in speciation and the production and maintenance of biodiversity, important issues in conservation and evolutionary biology.