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1
Sharp, Ashley Lawrence. "An experimental and theoretical analysis of optimal positioning behaviour of fish within shoals." Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268377.
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Taylor, John Stewart. "The evolution of repetitive DNA in the guppy (Poecilia reticulata) and the genetic structure of natural guppy populations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0019/NQ52715.pdf.
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Thomas, Philip Richard. "Group-living in the guppy Poecilia reticulata." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485597.
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The guppy Poecilia reticulata has proven a model species for behavioural ecology; in this thesis, its patterns of group-living were examined in a variety of contexts. These fish engage in inspection, the risky approaching of a predator to gain information on the threat posed. To lessen this risk, guppies may cooperate by approaching together, taking it in turns to advance. The temptation is for fish to defect by holding back and observing the inspection of others, gaining information at their partner's expense. Theory predicts that individuals should associate with those that have been previously cooperative in order to avoid being defected against. To test this, I quantified the social networks of wild-caught female shoals of guppies and then exposed them to a pike cichlid predator Crenicichla frenata. Guppies that inspected together frequently were both more cooperative and more associated in the network than infrequently inspecting partners. Simulating defection by preventing some fish inspecting. in similar female shoals, I found, contrary to predictions, that there was no change in the preference of others. to partner with them afterwards. Guppies appear to assort with respect to cooperation but not reassort in response to defection. Additional experiments found that the number of fish, and thus the number of partners to choose from, did not change how cooperative fish were during inspection, perhaps because of consistent partner choice. I then examined if these stable partnerships observed in the laboratory occurred in the much larger social networks seen in the wild. I found that female guppies of similar inspection tendencies interacted more often than predicted by random models. If guppies prefer shoaling with particular individuals over others, they may learn preferentially from others also. Testing shoals of domestic female guppies in a novel foraging task, naIve guppies performed the task fas~er when a trained fish was highly connected to them in their social network. However, if there were two trained fish with conflicting tasks, then they performed the task of the less connected fish faster. The network position of trained fish appears to impact upon the potential for social learning of naIve fish but other factors, e.g. the competitive ability of the trained fish, may influence how naIve fish act on that information. Thus we see that the benefits to a fish of shoaling with others depend upon the shoaling partners chosen and that guppies exercise this choice with care in a number of contexts.
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Mathisen, Maria Kristin. "Benefits of Multiple Mating in guppy (Poecilia reticulata)." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21411.
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Delaire, Lari. "Predation, parasitism and colour in natural guppy populations." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103592.
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Many studies of evolution adopt a unifactorial approach, where a single causal force appearing to account for a majority of the phenotypic variation becomes the focal point of investigation. However, it seems certain that no single force acts to the complete exclusion of other forces, and so multi-factorial studies can make a crucial contribution to our understanding of the evolution of phenotypic variation. In the Trinidadian guppy system, natural selection acting via predation has long been recognized as playing an important role in shaping trait variation. However, other environmental factors also likely contribute, and my thesis explores the potential role of one of them: parasitism. I specifically focus on Gyrodactylus, a monogenean ectoparasite that has important effects on many fish species and coexists with guppies in the wild. I evaluate the extent to which parasitism varies among guppy populations, particularly in relation to predation. I then ask whether parasitism influences phenotypic variation in guppy traits. This work was executed through a large-scale survey in northern Trinidad, where 26 guppy populations of known predation level (high or low) were surveyed across 10 different rivers. Individual guppies were scanned for Gyrodactylus and then photographed for image analyses aimed at quantifying body size and aspects of male colour. I found that among-population variation in parasitism levels was consistent between two dry seasons, and that high-predation localities tend to have higher levels of parasitism than do low-predation localities. However, I found few effects of parasitism on guppy traits and no major modifying influence of parasitism on inferences about the role of predation. Although more work certainly needs to be done with respect to parasitism, our results suggest it might be more profitable to concentrate on other potential causal factors that shape guppy trait variation.De nombreuses études sur l'évolution adoptent une approche uni-factorielle qui se concentrent sur une seule force pouvant expliquer la plupart de la variation phénotypique observée. Cependant, il est évident qu'aucune force n'exerce son effet de façon isolée. C'est pourquoi les études multi-factorielles apportent une contribution cruciale à notre compréhension de l'évolution de la variation phénotypique. Dans le système d'étude des guppies de Trinité, la sélection naturelle imposée par les prédateurs a depuis longtemps été considérée comme un facteur important dans l'élaboration de la variation au niveau des traits. Cependant, d'autres facteurs environnementaux contribuent également à cette élaboration, notamment le parasitisme. Je me penche sur le rôle potentiel que peuvent avoir les parasites du genre Gyrodactylus sur les traits des guppies. Ces ectoparasites monogènes exercent de nombreux effets sur plusieurs espèces de poissons et coexistent avec les guppies dans leur environnement naturel. J'évalue le niveau de variation du parasitisme entre les populations de guppies, et plus spécifiquement en relation avec la prédation. J'explore par la suite l'influence potentielle du parasitisme sur la variation phénotypique des traits des guppies. Pour ce faire, une étude de grande échelle a été effectuée sur 10 rivières dans le nord de Trinité, dans laquelle 26 populations sujettes à des niveaux de prédation connus (élevé ou bas) ont été inventoriées. L'état d'infection par les Gyrodactylus a été répertorié pour chaque guppy, puis les poissons ont été photographiés pour analyser les images dans le but de quantifier la taille corporelle ainsi que de nombreux aspects de la coloration chez les mâles. J'ai trouvé que les niveaux de parasitisme entre les populations étaient consistants entre les deux saisons sèches recensées, et qu'il y a une tendance pour les sites de haute prédation à avoir des niveaux de parasitisme plus élevés que les sites de basse prédation. Cependant, j'ai trouvé que la parasitisme avait peu d'effets sur les traits des guppies et aucune influence majeure n'a été trouvée sur les inférences concernant la prédation. Bien qu'il reste encore beaucoup de travail à faire en ce qui a trait au parasitisme, nos résultats suggèrent qu'il pourrait être plus profitable de se concentrer sur d'autres facteurs potentiels pouvant expliquer la variation de traits chez les guppies.
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Chapman, Ben. "Early experience and behavioural plasticity in the guppy." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494593.
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Croft, Darren P. "The social organisation of the guppy (Poecilia reticulata)." Thesis, University of Leeds, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396602.
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Barbosa, Miguel. "Female mating decisions in the Trinidadian guppy, Poecilia reticulata." Thesis, St Andrews, 2009. http://hdl.handle.net/10023/767.
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Lopez, Silvia. "Parasite mediated sexual selection in the guppy (Poecilia reticulata)." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300130.
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Archard, Gabrielle Ann. "Context-dependent mating behaviour in the guppy, Poecilia reticulata." Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437271.
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Shohet, Adam Joseph. "Mate choice and sexual selection in the guppy, Poecilia reticulata." Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269307.
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Smith, Elizabeth Jane. "Ultraviolet vision and mate choice in the guppy, Poecilia reticulata." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390642.
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Fernlund, Isaksson Erika. "Social learning and brain size in the guppy (Poecilia reticulata)." Thesis, Stockholms universitet, Zoologiska institutionen, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-185607.
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Gomide, Jefferson Mendes. "ESTIMATIVA DOS PARÂMETROS GENÉTICOS DE CARACTERES MORFOMÉTRICOS EM GUPPY (Poecilia reticulata)." Pontifícia Universidade Católica de Goiás, 2008. http://localhost:8080/tede/handle/tede/2423.
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Previous issue date: 2008-12-17The invasion of new environments is related to the genetic variability of the species. The guppy (Poecilia reticulata) is a species introduced accidentally or artificially, arisen from different populations of captivity around the world. In some countries, these introductions are made repeatedly, particularly to control the growth of disease-transmitting mosquitoes in small lakes and streams in tropical countries. The Guppy is feeding the larvae of mosquitoes, preventing it from coming into adult life. Because of the need to obtain a better understanding of the differentiation of introduced populations, and this may reduce the impact of the introduction of exotic species, since it is the third leading cause of extinction of native species, three populations in different cities of the state of Goias were collected, and their metric features analyzed. The review sought to determine the rate of divergence among populations of free life, which contribute to the understanding of the process of colonization of natural environments by this alien species. The results indicated that the divergence between the populations analyzed, for most of the features is very large, ie the rate of divergence is greater than expected by neutral evolution, so that directional selection is expected to be acting on these characteristics.
A invasão de novos ambientes se relaciona com a variabilidade genética das espécies. O Guppy (Poecilia reticulata) é uma destas espécies introduzidas acidentalmente ou artificialmente, advindo de várias populações de cativeiro em todo o mundo. Em alguns países, estas introduções se deram várias vezes, particularmente para o controle do crescimento de mosquitos transmissores de doenças, em lagos e pequenos riachos nos países tropicais. O Guppy se alimenta das larvas desses mosquitos, impedindo que cheguem à fase adulta. Devido à necessidade de se obter uma maior compreensão da diferenciação de populações introduzidas, e com isto poder reduzir o impacto da introdução de espécies exóticas, já que é a terceira causa de extinção de espécies nativas, foram coletadas três populações em cidades diferentes do estado de Goiás, e as suas características métricas analisadas. A análise procurou determinar a taxa de divergência, entre populações de vida livre, que contribuirá para a compreensão do processo de colonização dos ambientes naturais por esta espécie exótica. Os resultados indicaram que a divergência entre as populações analisadas, para a maioria das características é muito grande, ou seja, a taxa de divergência é maior do que a esperada pela evolução neutra, de modo que seleção direcional deve estar atuando sobre estas características.
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Stephenson, Jessica. "Predators, parasites, and the social behaviour of the guppy Poecilia reticulata." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/73819/.
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Predators can have both direct and indirect effects on how their prey interact with parasites. This thesis explores these effects using observational and experimental approaches. A behavioural experiment suggested that the direct effects of predators are size- and sex-biased, with small and male guppies, Poecilia reticulata Peters 1859, more prone to Gyrodactylus turnbulli Harris 1986 parasite-induced vulnerability to predation (Chapter 2). Trait-mediated indirect effects of predators also appear important to this host-parasite interaction, as revealed by surveys of natural Trinidadian populations under different predation regimes. First, predator-driven life history evolution predicts an apparent population divergence in parasite tolerance (Chapter 3). Similar divergence in a second trait, social behaviour, may drive sex- and age-biased parasitism: the guppies most liable to shoal have the highest infection probability (Chapter 4). Social behaviour is thus an important driver of parasite transmission, but how parasites affect social interactions remains poorly understood. The second part of this thesis investigates how guppies may use sensory information to mitigate this cost of sociality. Many fishes rely on chemical and visual information and the interaction between sensory modalities to behave appropriately; for example, chemical cues change how guppies respond to visual cues (Chapter 5). In a social context, guppies use both chemical and visual cues to detect infection in conspecifics, but only avoid those in the later stages of infection (Chapter 6). Infection avoidance behaviour is not innate, but likely results from juvenile guppies imprinting on cues of conspecifics, and associating with these cues in adulthood (Chapter 7). This imprinting-mediated avoidance appears to be adaptive: a transmission experiment showed that the onset of avoidance behaviour coincides with the stage of infection at which conspecifics are most infectious (Chapter 8). The sensory ecology of the host and the community in which it lives therefore have important implications for disease dynamics.
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Qualhato, Gabriel. "Efeitos toxicológicos de nanopartículas de maghemita (γ-Fe2O3) em células e tecidos de Poecilia reticulata." Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/8613.
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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
The environmental risk of nanomaterials (NMs) designed and used in nanoremediation process is of emerging concern, but their ecotoxilogical effects to aquatic organism remains unclear. In this present study, the citrate-coated (maghemite) nanoparticles (IONPs) were synthesized and its genotoxic, mutagenic, the melanomacrophage centers (MMC) response and hepatic histopathological biomarkers were investigated in female guppy. Fish were exposed to IONPs at environmentally relevant iron concentration (0.3 mg L-1) during 21 days and the animals were collected at the beginning of the experiment and after 3, 7, 14 and 21 days of exposure. The genotoxicity and mutagenicity were evaluated in terms of DNA damage (comet assay), micronucleus (MN) test, erythrocyte nuclear abnormalities (ENA) frequency and the liver were dissected and fixed dehydrated through increasing ethanol gradient, immersed in xylene PA, embedded in paraffin, performed of liver sections (5 μm thick) (3 sections per animal) in the microtome, stained by Mallory’s Trichrome and H. E. and analyzed. Results showed differential genotoxic and mutagenic effects of IONPs in the P. reticulata according to exposure time. The IONP induced DNA damage in P. reticulata after acute (3 and 7 days) and long-term exposure (14 and 21 days), while the mutagenic effects were observed only after long-term exposure. The DNA damage and the total ENA frequency increase linearly over the exposure time, indicating a higher induction rate of clastogenic and aneugenic effects in P. reticulata erythrocytes after long-term exposure to IONPs. Guppies exposed to IONPs showed increasing in the number, area and perimeter of MMC when compared to the unexposed ones, especially after 7 days of exposure. The results showed an increase in the frequency of histopathological changes in fish after the 7 days of exposure to IONPs, such micro- and macro-vesicular steatosis, melanomacrophage aggregates, exudate and haemorrhagic foci. The acute (3 and 7 days) and long-term (14 and 21 days) exposure of P. reticulata to IONPs induced high histopathological indexes associated with circulatory disorders and inflammatory responses. Results indicated that blood system and liver tissue of P. reticulata are excellent target organs to studies the ecotoxicity of IONPs. Confirming that P. reticulata is a biomonitor specie indicated for studies of ecotoxicity of IONPs.
O risco ambiental dos nanomateriais projetados e utilizados para nanoremediação se mostram hoje de grande interesse econômico e ambiental, mas seus efeitos ecotóxicológicos para os organismos aquáticos ainda permanecem obscuros. Neste presente estudo, as nanopartículas de oxido de ferro funcionalizadas com citrato (maghemita) (NOFs) foram sintetizadas e seus efeitos genotóxicos, mutagênicos, e histopatológicos foram investigados em fêmeas de Poecilia reticulata. Os peixes foram expostos a maghemita em concentrações de ferro ambientalmente relevantes (0,3 mg.L-1) durante 21 dias e os animais foram coletados no início do experimento e após 3, 7, 14 e 21 dias de exposição. A genotoxicidade e a mutagenicidade foram avaliadas por meio do dano causado ao DNA (Ensaio cometa), o teste do micronúcleo (MN) e anormalidades nucleares de eritrócitos (ANE) avaliaram o potencial mutagênico. Os fígados foram dissecados, fixados, desidratados em etanol, imersos em xilol, embebidos em parafina, e seccionados com 5 μm de espessura, os cortes corados em H.E. e Tricrômico de Mallory foram analisados e obtidos dados histomorfométricos. Os resultados mostraram efeitos genotóxicos e mutagênicos diferenciais das NOFs em P. reticulata de acordo com o tempo de exposição. As NOFs induziram danos ao DNA após exposição aguda (3 e 7 dias) e de longo prazo (14 e 21 dias), enquanto os efeitos mutagênicos foram observados somente para a exposição prolongada. O dano no DNA e a frequência total de ANE aumentaram linearmente ao longo do tempo de exposição, indicando uma maior taxa de indução de efeitos clastogênicos e aneugênicos em eritrócitos de P. reticulata após exposição prolongada a NOFs. Os guppies expostos também mostraram aumento do número, área e perímetro dos MMC quando comparados ao grupo controle, especialmente após 7 dias de exposição. Os resultados mostraram um aumento na frequência de alterações histopatológicas em peixes após os 7 dias de exposição as NOFs, tais como esteatose micro- e macro-vesicular, aumento dos MMC, exsudatos e focos hemorrágicos. A exposição aguda (3 e 7 dias) e a longo prazo (14 e 21 dias) de P. reticulata a NOFs induziu índices histopatológicos elevados associados a distúrbios circulatórios e respostas inflamatórias. Os resultados indicaram que os tecidos sanguíneo e hepático dos guppies são excelentes órgão alvo para estudar a ecotoxicidade das NOFs, confirmando que o P. reticulata é uma espécie biomonitora indicada para estudos sobre a ecotoxicidade das NOFs.
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Bundsen, Andreas. "Artificial selection for large and small relative brain size in guppies (Poecilia reticulata) results in differences in cognitive ability." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-192953.
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Vertebrate brain size is remarkably variable at all taxonomic levels. Brains of mammals forexample, range from 0.1 gram in small bats (Chiroptera) to about 8-9 kilos in Sperm whales(Physeter macrocephalus). But what does this variation in size really mean? The link between brainsize and cognition is debated due to, for instance the difficulties of comparing cognitive ability indifferent species. A large number of comparative studies continue to provide information aboutcorrelations found both within and between species. The relative size of the brain is an example of apopular measurement that correlates with cognitive ability. But to date, no experimental studieshave yielded any proof causality between relative brain size and cognitive ability. Here I usedguppies selected for either large or small relative brain size to investigate differences in cognitiveperformance of a quantity discrimination task. The results from this experiment provideexperimental evidence that relative brain size is important for cognitive ability, and that a differencein cognitive ability could be obtained already after two generations of selection experiments onrelative brain size in a vertebrate.Artificial Selection on Relative Brain Size in the Guppy Reveals Costs and benefits of Evolving a Larger Brain
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Paiva, Sérgio Côrtes. "CURVAS DE CRESCIMENTO MORFOMÉTRICO DE GUPPY (Poecilia reticulata) DO NASCIMENTO À MATURIDADE SEXUAL." Pontifícia Universidade Católica de Goiás, 2012. http://localhost:8080/tede/handle/tede/2141.
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Previous issue date: 2012-02-07The ornamental aquaculture in the world is an activity of economic and social importance since it can be conducted under family, generating income and serving as an option to keep the population in the rural areas. The cultivation of ornamental fish is considered one of the most profitable sectors of Brazilian fish. The Guppy is an omnivore and teleost ornamental fish originating in Central America. This is one of the best-selling fish in the world followed by Kinguios. One of the characteristics of the Guppy sexual dimorphism is present. The Guppies born with about 6mm long. There are several factors that affect the growth rate of fish, such as temperature, pH, ammonia levels, dissolved oxygen in water, power, density, and genetics. This work aims to establish morphometric growth curves based on age for the Guppy, using - if different nonlinear models. The study was conducted in the Research Lab and Production of Aquatic Organisms (LAPO), located at Campus II of the Pontifical Catholic University of Goiás (PUC - GO) in the period from February 11 to June 21, 2011. We used 128 fish species Poecilia reticulata. Were made during the trial period 64 randomized trials, with a total of 128 fish Guppy, and 2 individuals / sample of each box. For morphometric measurements were made of the head length (CCAB), standard length (CP), Height (AND) and width (NLD). For each measure and reason morphometric growth curves were estimated using the roles of Von Bertalanffy, Richards, Brody, Gompertz and Logistics. The correlation between standard length, head length, width and height taken on the dorsal fin is high and Meaningful. The models of Gompertz, Brody and Bertalanffy were the ones that best described the growth of morphometric Guppies.
A aquicultura ornamental no mundo é uma atividade de importância econômica e social uma vez que pode ser conduzida em regime familiar, gerando renda e servindo como opção para manter a população rural no campo. O cultivo de peixes ornamentais é considerado hoje um dos setores mais lucrativos da piscicultura brasileira. O Guppy é um peixe ornamental teleósteo e onívoro originário da América Central. Este é um dos peixes mais vendidos no mundo seguido pelos kinguios. Uma das características do Guppy é apresentar dimorfismo sexual. Os Guppys nascem com aproximadamente 6mm de comprimento. Existem vários fatores que interferem na taxa de crescimento de peixes, tais como temperatura, pH, níveis de amônia, oxigênio dissolvido na água , alimentação, densidade e genética. O presente trabalho tem o objetivo de estabelecer curvas de crescimento morfométrico em função da idade para o Guppy, utilizando - se diferentes modelos não lineares. O estudo foi realizado no Laboratório de Pesquisa e Produção de Organismos Aquáticos (LAPOA), localizado no Campus II da Pontifícia Católica de Goiás (PUC GO), no período de 11 de fevereiro a 21 de junho de 2011. Foram utilizados 128 peixes da espécie Poecilia reticulata. Foram realizados durante o período experimental 64 amostragens aleatórias, com o total de 128 peixes Guppy, sendo 2 indivíduos/ amostragem de cada caixa. Para a avaliação morfométrica foram feitos medidas do comprimento da cabeça (CCAB), comprimento padrão (CP), Altura (AND) e Largura (LND). Para cada medida e razão morfométrica foram estimadas curvas de crescimento utilizando-se as funções de Von Bertalanffy, Richards, Brody, Gompertz e Logística. A correlação entre Comprimento Padrão, Comprimento da Cabeça, Largura e Altura tomadas à frente da nadadeira dorsal são altas e significativas. Os modelos de Gompertz, Brody e Bertalanffy foram os que melhor descreveram o crescimento morfométrico dos Guppies.
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Archer, S. N. "A microspectrophotometric study of visual pigment polymorphism in the guppy, Poecilia reticulata." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233767.
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Ariyomo, Tolulope Omolayo. "Personality traits of the zebrafish, Danio rerio and the guppy, Poecilia reticulata." Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/4673/.
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Deacon, Amy E. "The behavioural ecology of the Trinidadian guppy, Poecilia reticulata, as an invasive species." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/1689.
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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.
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Thomas, Dawn Karen. "The relationship between behavioural phenotypes and social interactions in the guppy (Poecilia reticulata)." Thesis, Bangor University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540740.
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Skinner, Andrew M. J. "Sexual selection in the zebra fish (Danio rerio) and the guppy (Poecilia reticulata)." Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419617.
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Hallgren, Stefan. "Brain Aromatase in the guppy, Poecilia reticulata : Distribution, control and role in behaviour." Doctoral thesis, Stockholm : Zoologiska institutionen, Stockholms universitet : Södertörns högskola, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-26942.
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Zajitschek, Susanne Biological Earth & Environmental Sciences Faculty of Science UNSW. "The interplay between sexual selection, inbreeding and inbreeding avoidance in the guppy, Poecilia reticulata." Publisher:University of New South Wales. Biological, Earth & Environmental Sciences, 2008. http://handle.unsw.edu.au/1959.4/41218.
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Inbreeding can have profound negative effects on individuals by reducing fertility and viability. In populations, inbreeding depression can reduce growth rates and increases extinction risk. The aims of this thesis are to investigate inbreeding depression in male guppies (Poecilia reticulata) and to study the evolution of mechanisms for inbreeding avoidance in females, using guppies from a feral population in Queensland, Australia. Male guppies are highly polymorphic in their sexual ornamentation, indeed they show one of the most extreme polymorphisms observed in nature. Female guppies exhibit complex mate choice based on preferences for ornamentation, as well as social context. I aim is to examine how these factors of inbreeding avoidance alter sexual selection. In male guppies I found strong inbreeding depression in male sperm numbers, which is amplified under semi-natural compared to laboratory conditions (Chapter 2). Moreover, inbreeding depression results in low fertility under sperm competition: an experiment using artificial insemination techniques reveals that highly inbred males are heavily disadvantaged in gaining paternity (Chapter 3). On population level, inbreeding depression is manifest in reduced growth rates, predominantly in the early stages of inbreeding (Chapter 4). Population growth at inbreeding coefficients f=0.375-0.59 did not seem to lead to inbreeding depression, whereas lower levels of inbreeding reduced population growth. Although the growth rates in inbred populations appear normal, severe inbreeding depression is uncovered after outbred immigrants are added. Specifically, male immigrants are most efficient in short-term genetic rescue, probably due to insemination of large numbers of females whereas females are limited in the number of eggs they can produce (Chapter 4). Male ornamental traits show significant inbreeding depression in semi-natural conditions only (Chapters 2 & 3). Inbreeding avoidance mechanisms seem to have evolved in females: they prefer courtship displays of non-inbred males (Chapter 2), unfamiliar males (Chapter 5) and males with rare patterns (Chapter 6). This preference might increase the mating success of immigrants, and may have evolved to facilitate the avoidance of inbreeding. Together with context-independent preferences for ornament combinations (Chapter 6), it also offers an explanation for the maintenance of polymorphism in this species.
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Boisjoly, Maryse. "A test of the trade-up hypothesis of mate choice in multiple guppy populations." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104788.
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The costs to females associated with polyandry are numerous. However, this mating strategy is very common in nature because mating with multiple males during the same reproductive cycle can also provide multiple benefits. Under such conditions, females can use different strategies to optimize the benefits of mate choice. Among these, the trade-up hypothesis is a model used to predict female mate choice when males are encountered sequentially: specifically, females mate with males of increased quality as they gain experience. These decisions are thought to be based on cues that indicate male quality to females. These cues, however, may well differ between populations as a result of adaptive divergence in response to different selective pressures. In this study, Trinidadian guppies were used to test the trade-up hypothesis and whether trade-up patterns differ among wild populations. Guppies from three populations were used to conduct within-population sequential mate choice trials. Each female was presented sequentially to the same two males on each of two consecutive days. Female responsiveness toward the two males was then compared and related to variation in male traits. Contradictory to previous work, we found no evidence that female guppies trade up with respect to any of the measured male traits, and that patterns of sequential mate choice did not differ between populations. Instead, it seems that females vary dramatically in responsiveness independent of male identity. In fact, time was the only factor that had an effect on female responsiveness. However, it remains possible that only some populations trade up and only under some conditions. Further work should focus on understanding under which circumstances females can trade up.Il existe de nombreux coûts associés à la polyandrie. Cette stratégie reproductrice est toutefois très répandue dans la nature parce que les femelles qui s'accouplent avec plusieurs mâles à chaque cycle reproducteur peuvent également en retirer de nombreux bénéfices. Dans de telles conditions, plusieurs stratégies peuvent être utilisées par les femelles afin d'optimiser les bénéfices lors du choix de partenaires. L'hypothèse du «trade-up» figure parmi ces stratégies. Ce modèle est utilisé pour prédire le choix de partenaires effectué par les femelles lorsque les mâles sont rencontrés de façon séquentielle. Alors qu'elles acquièrent de l'expérience, les femelles s'accouplent avec des mâles de qualité grandissante.Ces décisions sont prises en fonctions de signaux émis par les mâles qui agissent en tant qu'indicateurs de qualité pour les femelles. Ces signaux peuvent toutefois différer entre des populations qui sont sujettes à différentes pressions de sélection suite à de la divergence adaptative. Dans cette étude, les guppies de Trinité sont utilisés afin de vérifier l'hypothèse du «trade-up», et afin de vérifier si les stratégies diffèrent entre des populations sauvages. Des guppies originaires de trois populations ont été utilisés dans des expériences de choix séquentiel de partenaires. Chaque femelle a été exposée à deux mâles provenant de la même population sur une période de deux jours, de sorte qu'elle ait pu interagir de façon séquentielle avec les deux mâles durant chaque jour. La réceptivité des femelles envers les deux mâles a ensuite été comparée et mise en relation avec des différences de traits entre les deux mâles. Contrairement à ce qui a été reporté dans d'autres études, les femelles n'ont pas choisi leur partenaire en fonction de signaux visuels relativement supérieurs (trade-up), et le choix séquentiel de partenaires ne diffère pas entre les populations. Il semble que la réceptivité des femelles varie énormément d'un individu à l'autre, et que cette variabilité ne soit pas due à l'identité des mâles. Le temps est le seul facteur qui ait montré un effet significatif sur la réceptivité des femelles. Cependant, il demeure toujours possible que l'hypothèse du «trade-up» ne soit applicable qu'à certaines populations et dans certaines circonstances. Les travaux futurs devraient tenter de déterminer selon quelles circonstances l'hypothèse du «trade-up» s'applique aux guppies.
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Paxton, C. G. M. "Genetics and environmental components of behavioural variation within guppy, Poecilia reticulata, populations in Trinidad." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259896.
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Fiore, Palestina Guevara. "The role of olfactory cues in the mating behaviour of the guppy, Poecilia reticulata." Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515243.
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White, Stephen John. "The evolutionary genetics of behavioural variation : multivariate perspectives on personality in the Trinidadian guppy." Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/30848.
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Animal personality is found in a wide range of taxa, yet our knowledge of what maintains consistent among-individual variation in behaviour is still incomplete. Many personality traits are associated with fitness, leading to the expectation that, under selection, genetic (and among-individual) variation will be eroded over time. Several adaptive models have been developed in order to explain this maintenance of variation. These include state-dependence, state-behaviour feedback loops, life-history and behavioural coadaptation and the Pace of Life syndrome. These models represent good starting points for thinking about what drives and maintains among-individual variation in behaviour, and while empirical support for these models is mixed, one thing they do have in common is the assumption of a significant genetic basis underpinning personality traits. Significant heritability is required for an evolutionary response to selection and for among-individual variation to be adaptive. The univariate estimates of heritability for personality traits that are growing in the literature, while useful, are likely insufficient to predict how personality traits will respond to selection. This thesis uses the Trinidadian guppy, Poecilia reticulata, and other species to explore patterns of among-individual and genetic variation in personality traits, advocating the benefits of using multivariate perspectives throughout. Firstly, the among-individual covariance structure between measures of boldness, growth and metabolic rate are estimated in a test of the Pace of Life syndrome. Secondly, an appraisal of the relative strength of maternal and genetic effects on offspring personality and how it changes over ontogeny. Next, a comprehensive treatment of sexual dimorphism in behaviour and size followed by analysis of genotype-by-sex interactions using both univariate and multivariate methods. Finally, a comparative analysis of personality in 7 species of small fish, identifying the main axis of among-individual variation from a single assay in each and quantifying the phylogenetic signal.
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Perry, Hazel. "Genomic analysis of shifts in life history traits in the Trinidadian guppy, Poecilia reticulata." Thesis, Bangor University, 2015. https://research.bangor.ac.uk/portal/en/theses/genomic-analysis-of-shifts-in-life-history-traits-in-the-trinidadian-guppy-poecilia-reticulata(aac003e6-c2bd-493f-93d8-d2fe7a766b6e).html.
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It is widely accepted that size selective mortality induced by commercial fishing can and does cause changes in life history traits that include shifts in maturation age, growth rate and body size. However, whether these changes are the result of fisheries induced evolution (genetic change) or phenotypic plasticity is still unclear. Moreover, where evolution is rapid, epigenetic or regulatory change has also been found to drive major shifts in life history change. To examine the genetic and phenotypic response to size selective harvesting, a previous study (van Wijk 2011a) subjected guppies to divergent size-specific selection. Following selection, a significant difference in both body size and age at maturation was identified as well as signatures of selection at five candidate loci. The project described here utilised these selection lines to examine the genome wide factors contributing to such life history shifts. To assess the genome wide response to size selective harvesting, RAD sequencing was employed to identify and type large numbers of SNPs in individuals from the selection lines, as well as individuals from the generation prior to selection. Significant and consistent signs of selection were identified at 37 SNPs, the majority of which were located on the sex chromosome. The results showed that, in addition to previously observed genetic change, additional regions of the guppy genome responded to, and were associated with, observed phenotypic shifts. Variation in the level of predation in wild populations creates variation in life history traits similar to those seen after size selective harvesting. We therefore examined the 37 SNPs identified by the RAD sequencing of the selected lines in 18 populations of wild guppy. No consistent signs of selection were identified in these wild populations, suggesting that the genetic architecture underpinning variation in life history traits in the guppy varies in different populations. To determine the role of epigenetic change the focus has been on DNA methylation. In order to assess the levels of DNA methylation a technique known as methylation sensitive AFLP has been used. Using this technique, comparisons of the level of DNA methylation between both the selection lines and the before and after selection fish were made as well as comparisons in the levels of DNA methylation between a range of tissue types from the guppy. Results showed that patterns of DNA methylation differ significantly between different tissues in the guppy. Genome wide patterns of genome wide methylation did not differ significantly between the selection lines, however locus-specific variation in DNA methylation was identified.
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Rohyo, Izla. "No indications of socially induced changes in brain aromatase activity in guppy (Poecilia reticulata) males." Thesis, Södertörn University College, School of Life Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-1595.
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Aromatase is the enzyme that catalysis the conversion of androgens into estrogens. It´s a member of P450 cytochrome family and is encoded by the CYP19-gene. The enzyme aromatase has an important role in regulating physiological and behavioral sexual mechanisms. This includes for instance activation, motivation and maintenance of the reproductive behaviors. The sexual behavior is affected by a complex series of events that requires the connection of endogenous hormonal and neurochemical changes with social interactions, especially between the opposite sexes. The aim of the present study was to examine how social interactions effect the aromatase expression and activity in the guppy brain. Guppy males were introduced into four different social conditions: Isolated, all male conditions, heterospecific (with zebrafish females) and conspecific female guppies. The focal males were kept under these conditions for two respectively four days. The sexual behavior, of each of the focal males was recorded daily during 10 minutes. The males with the guppy females showed, in contrast to the males in the other groups, a high frequency of reproductive behaviors. The brains of the focal males were collected and the brain aromatase activity was measured using tritiated water assay. I have also tried to analyze the gene-expression of aromatase with RT-PCR. However I was unable to analyze the results with the RT-PCR, because of possible primer-dimerization. Due to the limited time schedule, we were not able to solve the problem. ANOVA performed on the aromatase activity, revealed no significant difference between the different treatment groups. The variance was highest in the zebrafish category and lowest in the isolated males. There was no significant correlation between the mean number of reproductive behaviors and the aromatase activity in males that were together with guppy females. The results do not support the hypothesis that social interactions can affect the brain aromatase activity in guppy males.
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Ward, Jonathan Richard. "The role of predation in prey behaviour using the Trinidadian guppy as a model system." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521542.
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Willing, Eva-Maria [Verfasser], and Detlef [Akademischer Betreuer] Weigel. "Next Generation Population Genomics in the Guppy (Poecilia reticulata) / Eva-Maria Willing ; Betreuer: Detlef Weigel." Tübingen : Universitätsbibliothek Tübingen, 2012. http://d-nb.info/1162699779/34.
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Eckerström, Liedholm Simon. "Brain size does not affect reproductive behaviour in male guppies (Poecilia reticulata)." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-233401.
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The processes and mechanisms that govern brain size evolution remain a widely discussed topic in evolutionary biology. How relative brain size relates to animal behaviour and cognition is even more controversial. Recent comparative and experimental studies have shown a positive relationship between relative brain size and complexity of behaviour. Some of the most important behaviours that have direct consequences for an individual’s fitness are reproductive behaviours, and they sometimes require quite complex behavioural repertoires. Selection for complex behaviour might therefore induce an expansion of brain size to allow for cognitively demanding tasks during courtship and mating. In the present study we investigated the effect of relative brain size on reproductive behaviour in male guppies (Poecilia reticulata), using fish from a recently established brain size artificial selection experiment. Females were paired with either a large- or a small-brained male, and we collected data on a suite of male courtship behaviours including sneak copulation attempts, courtship display, gonopodial swings and time spent following the female. Although the extent of orange colouration, a trait that varies across large- and small-brained males, affected male behaviour, we were not able to detect any difference in reproductive behaviour between the brain size selection lines. These results suggest that there is no strong association between male mating behaviour and relative brain size, and future studies will examine this question further. But currently, our results indicate that relative brain size might not be linked to reproductive behaviour to any significant extent, at least not in the guppy.
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Johnson, Lindsay. "Experimental study of the host-parasite relationship between the guppy (Poecilia reticulata), and Gyrodactylus turnbulli (Monogenea)." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46369.
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Camacho-Cervantes, Morelia. "Heterospecific social interactions of the invasive guppy (Poecilia reticulata) : a potential trait to enhance invasion success." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/6561.
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From all the species that arrive to a novel environment, very few manage to form a viable population. The guppy, a very successful invader, is a highly social species that performs some of its vital tasks (e.g., foraging, avoiding predators) in groups. This thesis aimed to quantify heterospecific association benefits that enhance invasion success. Interactions between invaders and natives could be one of the environmental characteristics of a place that increase its risk of invasion. I evaluated the tendency of an invasive species to associate with native individuals with similar ecological requirements. I tested the hypothesis that invaders gain exploring, acquisition of information and foraging benefits when socializing with natives. In these experiments I used the guppy as the invasive model species and endangered native Mexican topminnows (Poeciliopsis infans, Skiffia bilineata, Ameca splendens, Zoogoneticus tequila, Xenotoca eiseni and Girardinichthys viviparous). I found that guppies shoal with other species in Trinidad (Poecilia picta and Poecilia sphenops), where they are native (Chapter 2) and that this trait remains when they are invasive (Chapter 3). Guppies are equally willing to explore novel environments when accompanied by heterospecifics or conspecifics. Guppies are more willing to explore complex environments than simple ones. Moreover, when exploring simple environments they have a higher association tendency, regardless of the partner' species (Chapter 4), which could lead them to acquire the benefits of grouping behaviour and avoid Allee effects - the disadvantages of being part of a small group. In the contexts in which they were tested guppies gained as much information by associating with heterospecifics as with conspecifics (Chapter 5). Finally, I found that when shoaling in bigger shoals guppies are able to locate food faster and spent more time foraging. The benefits of increased shoal size were maintained when the additional guppies were replaced with heterospecifics. However, they derive more benefits from the species they are more willing to associate with (Chapter 6). These results uncover a mechanism enabling founding individuals to survive during the most vulnerable phase of an invasion and help explain why guppies have established viable populations in many parts of Mexico as well as in every continent except Antarctica.
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Corral, López Alberto. "The link between brain size, cognitive ability, mate choice and sexual behaviour in the guppy (Poecilia reticulata)." Doctoral thesis, Stockholms universitet, Zoologiska institutionen, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-148547.
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Competition over access for mates has led to the evolution of many striking examples of morphological traits and behaviour in animals. The rapid development of the sexual selection field in recent decades have dramatically advanced our understanding of what traits make individuals more successful in attracting mates and how preferences for mates evolve over time. However, till now, research in this field has put less emphasis on the mechanisms that underlie variation in mate choice and sexual behaviour. Cognitive processes could potentially be key drivers of individual variation in mating preferences and sexual behaviours and therefore deserve further investigation. In this thesis, I used guppies artificially selected for relative brain size as the model system to study the association between brain size, cognitive ability and various aspects of mate choice. Previous studies in this model system showed that large-brained individuals of both sexes outperformed small-brained individuals in cognitive tests. Here I quantified their sexual behaviours and mating preferences to provide novel empirical data concerning the association between brain size, cognitive ability and sexual selection. In dichotomous choice preference tests based on visual cues, comparisons between large-brained and small-brained guppies showed important differences in their assessment of mate quality. These results are not driven by pre-existing visual biases caused by the artificial selection since further investigation of the visual capacity of these fish detected no differences between large-brained and small-brained individuals in their sensitivity to colour or in their capacity to resolve spatial detail. I also quantified sexual behaviour in male guppies artificially selected for relative brain size and found no difference in the behaviours of large-brained and small-brained males in a single male-single female non-competitive scenario. On the contrary, in a more complex social setting I found a reduction in large-brained males in the rate of courtship towards females and dominance displays towards other males when exposed to different degrees of predation threat and different numbers of male competitors. However, this reduction in behavioural intensity did not result in a lower access to copulation with females for large-brained males. I likewise evaluated female sexual behaviour and found that large-brained females had higher behavioural flexibility such that they decreased their receptiveness towards males more strongly under higher levels of predation threat. Together, these results provide novel empirical evidence that brain size and cognitive ability are tightly linked to mating preferences and sexual behaviours. These findings suggest that brain size and cognitive ability might be important mechanisms behind variation in mating preferences and in sexually selected traits across and within species.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 5: Manuscript.
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Piyapong, Chantima. "Factors Underlying Shoal Composition in the Trinidadian Guppy (Poecilia reticulata): the Effects of Predation and Sex Differences." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491637.
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Sievers, Caya. "Enemy within the gates : reasons for the invasive success of a guppy population (Poecilia reticulata) in Trinidad." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/1865.
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The invasion of individuals into new habitats can pose a major threat to native species and to biodiversity itself. However, the consequences of invasions for native populations that are not fully reproductively isolated from their invaders are not yet well explored. Here I chose the Trinidadian guppy, Poecilia reticulata, to investigate how different population traits shaped the outcome of Haskins's introduction, a well-documented invasion of Guanapo river guppies into the Turure river. I especially concentrated on the importance of behaviour for invasive success. I investigated if the spread of Guanapo guppies is due to superiority in behaviour, life-history and/or genetics, or if the outcome of this translocation is due to chance. Despite the fact that by today the invasive front has passed the Turure's confluence with the River Quare many kilometres downstream of the introduction site, and the original genotype only survives in small percentages, as was revealed by genetic analysis in this and other studies, no obvious differences between invasive and native populations could be detected in any of the tested behavioural, life-history and genetic traits. When tested for mate choice, neither Guanapo nor Oropuche (Turure) males seemed to be able to distinguish between the population origin of females, but courted and mated at random. At the same time, females did not prefer to school with individuals of the same population over schooling with more distantly related females. The formation of mixed schools after an invasive event is therefore likely. Because female guppies showed a very low willingness to mate, even after having been separated from males for up to six months, sperm transfer through forced copulations will become more important. Taken together, these behaviours could increase the speed of population mixing after an invasion without the need for behavioural superiority of the invasive population. When tested for their schooling abilities, offspring of mixed parentage, in contrast to pure breds, displayed a large amount of variety in the time they spent schooling, a circumstance that can potentially influence survival rates and therefore the direction of gene pool mixing. Guanapo fish did not show reproductive superiority in a mesocosm experiment, where both populations were mixed in different proportions. On the contrary, in two out of three mixed treatments, the amount of Oropuche (Turure) alleles was significantly higher than expected from the proportion of initially stocked fish. The almost complete absence of distinguishable traits other than genetic variation between the examined populations that belong to different drainage systems, opposes the recent split of the guppy into two different species following drainage system borders, as is argued in this thesis. However, the successful invasion of the Turure by Guanapo guppies and the nearly entire disappearance of the original population can be explained in absence of differing population traits. Here I demonstrate how behavioural and genetic interactions between subspecies influence the outcome of biological invasions and second, how factors other than population traits, such as the geographic situation, can produce an advantageous situation for the invader even in the absence of population differences.
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SOUZA, FILHO José de. "Efeitos tóxicos e genotóxicos do herbicida Roundup Transorb® em Guppy (Poecilia reticulata) submetido a tratamento agudo." Universidade Federal de Goiás, 2011. http://repositorio.bc.ufg.br/tede/handle/tde/1259.
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Previous issue date: 2011-01-31The effects of toxic, mutagenic and genotoxic on target organs and the fish genome has been the subject of many studies, especially those that seek to establish these bodies and responses of genes to environmental stimuli. Histopathological studies, mutagenic, genotoxic and Poecilia reticulata (Guppy) were motivated by the scarcity of data in the literature concerning the effects of the formulation of the herbicide Roundup Transorb®. With everything, we sought to ascertain the effects produced by this formulation that is widely used in the Midwest of the country. This study aimed to evaluate the toxicity and mutagenic and genotoxic herbicide R. Transorb® in liver, gill and erythrocytes of the guppy, calculating and applying the LC50 test micronucleus (MN) and Comet assay (AC). The toxicity bioassays were performed to calculate the LC50;12-96h, to evaluate the effects of sublethal concentrations of herbicide subjected to acute treatment. We used 36 adult fish, weighing on average 0.496 g ± 0.28 g to calculate the LC50 and 75 adult fish also carry the MN and AC. During exposure to the herbicide was observed fish behavior at all concentrations and controlled chemical and physical changes of water. The erythrocytes were obtained by centrifugation of the gills being added to precipitate fetal calf serum, and then dripped on the slides to make the smear and electrophoresis. For the analysis of plates, 75.000 cells were counted and stipulate the frequency of occurrence of Nuclear Morphological Changes (AMNs) and AC were analyzed for 100 cells per specimen. The LC50; 12, 24, 48, 72 e 96h of R. Transorb® were 11:24, 8:55, 6.5, 6.10 and 5.65μl/L, respectively, indicating that this species is very sensitive to the herbicide studied in relation to other tropical species analyzed. These factors may be related to different formulations of herbicides and their respective surfactants. It was found that the mortality rate of fish poisoned by the herbicide increased as exposure concentrations increased. The values of LC50,12-96h show a downward trend over time, suggesting that during periods of reduced exposure will require greater amounts of herbicide to cause mortality of 50% of the population of animals. Animals exposed to the herbicide showed behavioral changes varied, such as aggressiveness, irritability, loss of the escape reflex, darkening of the body surface and banging against the wall of the aquarium. In addition, R. Transorb® hitológicas induced liver changes appreciably impairing the normal functioning of this organ. In MN and EC was possible to detect significant genotoxic and mutagenic effects in erythrocytes and gill cells, occurring gradual increase in the number of cells with AMNs and ADN damage under higher concentrations,indicating concentration-dependent effect. This herbicide has acute toxicity to guppy, promoting behavioral changes, possibly acting in a manner damaging to the liver but also in the nervous system and gill. These results also suggest that the formulation of this herbicide has genotoxic and mutagenic in erythrocytes and gill cells detected by the MN and AC. Therefore, it confirms the high risk of herbicide to the environment, its contamination may present a strong threat to populations of fish and other organisms both vertebrates and invertebrates and human health.
Os efeitos de substâncias tóxicas, mutagênicas e genotóxica sobre órgãos-alvos e o genoma de peixes tem sido objeto de muitos estudos, sobretudo daqueles que buscam estabelecer respostas destes órgãos e dos genes aos estímulos ambientais. Estudos histopatológicos, mutagênicos, genotóxicos e em Poecilia reticulata (Guppy) foram motivados pela escassez de dados na literatura referente aos efeitos provocados pela formulação do herbicida Roundup Transorb®. Com tudo, pretendeu-se conhecer os efeitos produzidos por essa formulação que é bastante utilizada no Centro-Oeste do país. O presente trabalho teve como objetivo avaliar a ação tóxica, mutagênica e genotóxica do herbicida R. Transorb® em fígado, brânquia e eritrócito do guppy, calculando a CL50 e aplicando Teste de Micronúcleo (MN) e Ensaio Cometa (EC). Os bioensaios de toxicidade foram realizados para calcular a CL50,12-96h, avaliar os efeitos das concentrações subletais do herbicida submetido a tratamento agudo. Utilizou-se 36 peixes adultos, pesando em média 0,496g ± 0,28g para cálculo da CL50 e 75 peixes também adultos para realizar o MN e EC. Durante a exposição ao herbicida observou-se o comportamento dos peixes em todas as concentrações e controlada as variações químicas e físicas da água. Os eritrócitos foram obtidos pela centrifugação das brânquias sendo adicionado soro fetal bovino ao precipitado, e posteriormente gotejado sobre as lâminas para realizar o esfregaço e eletroforese. Para a análise das lâminas, foram contadas 75.000 células e estipulada a frequência de ocorrência de Alterações Morfológicas Nucleares (AMNs), e para EC foram analisadas 100 células por espécime. A CL50; 12, 24, 48, 72 e 96 h do R. Transorb® foram de 11.24; 8.55; 6.5; 6.10 e 5.65μl/L, respectivamente, indicando que esta espécie é bastante sensível ao herbicida estudado em relação às demais espécies tropicais analisadas. Esses fatores podem estar relacionados às diferentes formulações dos herbicidas e seus respectivos surfactantes. Verificou-se que a porcentagem de mortalidade dos peixes intoxicados pelo herbicida aumentou à medida que as concentrações de exposição aumentaram. Os valores da CL50; 12- 96 h apresentam tendência de queda ao longo do tempo, sugerindo que em períodos de menor exposição serão necessárias quantidades maiores de herbicida para causar a mortalidade de 50% da população de animais. Os animais expostos ao herbicida apresentaram alterações comportamentais variadas, tais como: agressividade; irritabilidade; perda do reflexo de fuga; escurecimento da superfície corporal e choque contra a parede do aquário. Além disso, o R. Transorb® induziu alterações hitológicas hepáticas prejudicando de forma sensível o funcionamento normal deste órgão. No MN e EC foi possível detectar efeitos mutagênicos e genotóxicos significativos nos eritrócitos e células da brânquia, ocorrendo aumento gradual no número de células com AMNs e com danos ao DNA de acordo com aumento das concentrações, indicando efeito concentração-dependente. Este herbicida apresenta toxidade aguda para guppy, promovendo alterações comportamentais, agindo possivelmente de forma danosa não só no fígado, mas também no sistema nervoso e branquial. Tais resultados sugerem também que a formulação deste herbicida possui ação genotóxica e mutagênica em eritrócitos e células branquiais detectados através dos MN e EC. Por tanto, se confirma o alto risco deste herbicida ao meio ambiente, sua contaminação pode apresentar forte ameaça para as populações de peixes e outros organismos tanto vertebrados como invertebrados e saúde do homem.
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Nath, Pulak Ranjan. "Dietary supplementation with the microalga Parietochloris incisa in guppy (Poecilia reticulata) fry : effect on survival and stress resistance /." [Sedeh Boker, Israel] : Ben-Gurion University of the Negev, 2008. http://aranne5.lib.ad.bgu.ac.il/others/NathPulakRanjan.pdf.
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Gheorghiu, Cristina. "Concentration-dependent effects of waterborne zinc on the interactions between Gyrodactylus turnbulli (Monogenea) and the guppy (Poecilia reticulata)." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102979.
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This research investigated the effects of waterborne zinc (Zn) on the interactions between guppies, Poecilia reticulata (Peters), and Gyrodactylus turnbulli Harris, 1986, a monogenean parasite of its skin and fins. The first objective was to determine if sublethal concentrations of waterborne Zn (up to 240 mug/L added to artificial freshwater) exerted a concentration-dependent effect on the population dynamics of Gyrodactylus on isolated guppies. Whereas survival of uninfected fish was unaffected, mortality of infected fish increased linearly with increasing Zn concentration. In addition, the improved parasite population growth at concentrations up to 120 mug Zn/I suggested either that the elevated Zn promotes survival and/or reproduction of the parasite, or impairs host defense mechanisms. Analysis of lifetime survival and reproduction of individual parasites on and off the fish revealed Zn toxicity to the parasite as survival of detached parasites decreased linearly with increasing Zn concentration and parasite survival on the host was also lower at the highest Zn concentrations. Also, all morphological parameters decreased linearly in response both to increasing concentration and duration of exposure to waterborne Zn. The guppy epidermis responded rapidly to both infection and waterborne Zn, and the cumulative effects of these combined stressors were synergistic for epidermal thickness and mucous cell numbers, but antagonistic in terms of mucin composition. Both Zn and infection induced mucous production, but at elevated Zn concentrations and/or at high parasite burdens, the capacity for continued mucous production was apparently exceeded. I hypothesize that this condition is favorable for parasite survival because of the impaired host response; but unfavorable for host survival because of the high numbers of pathogenic parasites and the inability to control entry of Zn into host tissues. In conclusion, sublethal concentrations of waterborne Zn are more detrimental to the infected host than to the parasite.
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McMullan, Mark. "Host-parasite co-evolution and genetic variation at the major histocompatibility complex in the Trinidadian guppy (Poecilia reticulata)." Thesis, University of Hull, 2010. http://hydra.hull.ac.uk/resources/hull:5820.
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The Major Histocompatibility Complex (MHC) is a region of the vertebrate genome believed to be responsible for an individual's ability to detect and recognise invading parasites. The MHC molecule has been shown to bind to short fragments of parasite and present these to the adaptive immune system. Theory developed to describe the maintenance of polymorphism within the MHC has focussed on the principle that different MHC alleles recognise different groups of parasites and that parasite diversity maintains diversity in the MHC (i.e. Red Queen dynamics). Nevertheless, after 50 years of research, the precise mechanism for the maintenance of extraordinary levels of polymorphism in the MHC remains yet to be resolved. In the present thesis, I use guppies (Poecilia reticulata) as a model to investigate the role of parasites in the maintenance of polymorphism in the MHC. In a study of spatial variation of both MHC and microsatellite variation, I find evidence to suggest that upstream populations of guppies have small population sizes and reduced gene flow into the population. However, these populations of guppies maintain similar levels of MHC polymorphism to that of larger populations of guppies further downstream. The maintenance of MHC in small upstream populations provides evidence for selection for the maintenance of MHC polymorphism despite the effect of random genetic drift. This finding is particularly interesting given that I show that this small upstream population has a significantly reduced parasite fauna. These data therefore provide evidence for other sources of selection on the MHC such as sexual selection or Associative Balancing Complex (ABC) evolution. Balancing selection maintains polymorphism above that expected under a neutral model of evolution. However, balancing selection is a general term that encompasses several distinct mechanisms, including negative frequency dependent selection (rare allele advantage), overdominance (heterozygote advantage) and selection that favours distinct alleles in different times and/or places (fluctuating selection). I use a temporal dataset of MHC and microsatellite variation to distinguish between these different models of balancing selection. In particular, I evaluate the ability of the different models of balancing selection to explain the empirical data of two guppy populations sampled in 2001 and 2007.1 conclude that the relatively low level of spatial genetic divergence of the MHC in 2001 is most consistent with the overdominance and negative frequency dependent selection models of balancing selection. By contrast, the data in 2007 suggest that MHC is subject to fluctuating selection, showing a higher level of spatial genetic differentiation than the microsatellites. Overtime, the MHC appears to change more rapidly than neutral microsatellite loci. Using a verbal model, I argue that this pattern of temporal genetic divergence and the rapid turnover of MHC alleles is consistent with all types of balancing selection. Balancing selection increases the effective migration rate, resulting in a rapid differentiation of the MHC gene pool over generations. Such allelic turnover can however only be realised in a metapopulation with a large gene pool of MHC alleles. Both these conditions (i.e. a source-sink metapopulation with circa 85 MHC alleles) have recently been demonstrated for guppy populations in the Caroni Drainage in Trinidad by different authors. Importantly, these findings demonstrate that in an open metapopulation, the impact of migration can differ dramatically between neutral genes and genes under balancing selection. Using a simulation model, I further explore whether the combination of balancing selection (in particular, overdominance) and gene flow in a metapopulation system can explain the large observed spatio-temporal differentiation of the MHC. Traditionally, authors have interpreted large temporal fluctuations in MHC allele frequencies as evidence for a coevolutionary arms race between host immune genes and parasite virulence genes (i.e. Red Queen dynamics). In this theoretical chapter, I explore whether such data can also be explained by simple overdominant selection in combination with migration from a source population with many distinct MHC alleles. I find that the commonly held assumption that balancing selection homogenises gene frequencies and reduces the level of genetic differentiation (G'sr) is not always correct, and it depends on the interaction between evolutionary forces and population demography. Furthermore, I demonstrate that balancing selection (overdominance) can explain the rapid turnover in MHC alleles, and that this observation should not be taken as evidence of Red Queen dynamics through host-parasite co-evolution. Altogether, this thesis highlights two main considerations that should be made in future studies of the MHC. Firstly, other sources of balancing selection should be considered in addition to parasite selection, particularly where no causal relationship between parasites and MHC alleles has been identified. Secondly, population demography can have a different impact on the population genetics of the MHC compared to that of neutral loci. The effect of a higher effective migration rate on MHC alleles is all too often interpreted as evidence for changes in the direction of parasite-mediated selection (i.e. Red Queen dynamics). However, theoretically, other forms of balancing selection, including overdominance, negative frequency dependent selection, fluctuating selection and ABC evolution, can also drive the temporal dynamics of the MHC.
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Kottler, Verena [Verfasser], and Christine [Akademischer Betreuer] Dreyer. "Pigment cell organization and genetic analysis of color pattern formation in the guppy (Poecilia reticulata) / Verena Kottler ; Betreuer: Christine Dreyer." Tübingen : Universitätsbibliothek Tübingen, 2015. http://d-nb.info/1197058036/34.
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Sharma, Eshita [Verfasser], and Detlef [Akademischer Betreuer] Weigel. "Transcriptome Assembly and Molecular Evolutionary Analysis of Sex-Biased Genes in the Guppy (Poecilia reticulata) / Eshita Sharma ; Betreuer: Detlef Weigel." Tübingen : Universitätsbibliothek Tübingen, 2015. http://d-nb.info/1163462136/34.
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MONTEIRO, André Luiz Viard Walsh. "Desempenho do Guppy (Poecilia reticulata) em modelos de ansiedade: campo aberto, preferência claro-escuro e labirinto em cruz com rampa." Universidade Federal do Pará, 2016. http://repositorio.ufpa.br/jspui/handle/2011/9041.
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O uso de modelos animais em pesquisa experimental nas últimas décadas tem se mostrado mais diversificado do que o modelo clássico através do uso de roedores ou primatas. Isso se dá principalmente pelos avanços nos estudos moleculares, morfológicos e funcionais que revelaram uma grande homologia entre os vertebrados. Nesta perspectiva, o peixe Zebrafish (Danio rerio) tem se mostrado como o animal não-mamífero com maior ascensão como animal de estudo em ciências biológicas nas últimas décadas. Entretanto, outras espécies de peixes também se mostram promissoras como alternativas de uso como modelo animal. Este estudo utilizou o Guppy (Poecilia reticulata) como modelo para pesquisa em comportamento através de diferentes abordagens experimentais. No estudo I, guppies foram expostos e reexpostos em diferentes turnos (manhã, tarde, noite e madrugada) nos testes de campo aberto e preferência claro-escuro. Os resultados encontrados mostram que em ambos os testes, machos e fêmeas apresentam diferenças comportamentais, sendo sensíveis a reexposição, com capacidade de aprendizagem e controle do ciclo circadiano. No estudo II, foi desenvolvido um labirinto em cruz com rampa no qual se verificou a sensibilidade da espécie ao aparato, o perfil de resposta mediante reexposição e o efeito de drogas. Os resultados revelaram sensibilidade ao aparato para uma altura de coluna d’água de 8cm e 5 minutos de sessão e diferenças entre os sexos e aprendizagem por habituação ao longo das reexposições. O estudo farmacológico indica que neste aparato a espécie é sensível a drogas ansiolíticas e ansiogênicas. Ao final, pode-se concluir que o Guppy apresenta comportamento similar e respostas as drogas compatível com os dados descritos para Zebrafish. Tais similaridades reforçam o uso de peixes como uma alternativa ao uso de mamíferos na experimentação animal.
The use of animal models in experimental research in the last decades has shown to be more diversified than the classical model through the use of rodent or primate. This is mainly by advances in molecular, morphological and functional studies that revealed a big homology between the vertebrates. On this perspective, the Zebrafish (Danio rerio) has shown to be the non-mammal animal with biggest ascension as a study model in biological sciences in the latest decades. However, other species of fish also show to be promising as alternatives of use as animal model. This study used Guppy (Poecilia reticulata) as model for the research in behavior through different experimental approaches. In study I, guppies were exposed and re-exposed in different shifts (morning, afternoon, evening and night) in the open field test and light-dark preference. The found results show that in both tests, male and female present behavioral differences, being sensitive to re-exposure, with capacity of learning e controlling of the circadian cycle. In study II, was developed a plus-maze with ramp where it was verified the sensibility of the specie to the apparatus, the profile of response upon re-exposure and the drug effect. The results revealed sensibility to the apparatus with a height of water column at 8 cm and 5 minutes of session and differences between sex and learning by habituation along the re-expositions. The pharmacological study indicates that in this apparatus, the specie is sensitive to anxiolytic and anxiogenic drugs. Finally, we can conclude that Guppy presents similar behavior and drug responses compatible with the data described to the Zebrafish. These similarities reinforce the use of fishes as an alternative to the use of mammals in animal experimentation.
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Dimitriadou, Sylvia. "Cooperation in a dynamic social environment." Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/33704.
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Cooperative behaviour among unrelated individuals is an evolutionary paradox. Research suggests that an individual’s propensity to cooperate and its response to experiencing cooperation or defection from its social environment consistently varies among individuals and as a function of external factors. The biological and psychological underpinnings of such behavioural variation remain unknown; they can, however, provide more insight into the evolution and maintenance of cooperation among non-kin. This thesis explores the proximate effects of experiences of cooperation or defection from the social environment, as well as possible proximate drivers of cooperative behaviour, using the Trinidadian guppy (Poecilia reticulata) as a study system. Firstly, the behavioural rules underpinning an individual’s decision to cooperate or not with unfamiliar individuals in the presence of specific or non-specific information were explored. When fish had information about their social partner’s cooperativeness, they behaved in a manner consistent with direct reciprocity, copying their partner’s last move. When paired with an ostensibly novel partner, a different, or at least additional, behavioural rule seemed to be employed. In order to help understand the drivers of individual variation in cooperative behaviour, phenotypic selection on cooperativeness was carried out over three filial generations, resulting in fish of high cooperativeness (HC) and low cooperativeness (LC). The divergence of individual cooperativeness observed between the two phenotypic selection lines suggests that cooperative behaviour in the context of predator inspection is at least in part heritable. Cooperative behaviour of F3 fish was found not to correlate with boldness or exploratory behaviour; HC and LC fish did, however, differ in some aspects of sociability and agonistic behaviour. Possible proximate neuromodulatory mechanisms underlying these differences in cooperativeness were also explored, focusing on brain expression patterns for the isotocin receptor (itr) gene in F3 females. HC females were found to have higher mid-section itr expression levels than LC females. Finally, I explored the effects of experiencing cooperation or defection on monoaminergic neurotransmission, which is thought to instantiate the effects of such experiences on the individual’s internal state. My findings suggest that experiencing cooperation or defection from the social environment affects internal state; this phenomenon may be crucial for the appropriate adjustment of the behavioural response to such experiences, and for the emergence of behavioural rules such as generalised reciprocity. Taken together these results suggest that neuromodulatory mechanisms are pivotal for the perception of stimuli from the social environment in the tested cooperative context and that variation in cooperative behaviour may be underpinned by individual differences in the structural properties of such systems. They also provide insight into how behavioural input may affect the behavioural response to such experiences, and ultimately how such mechanisms may lead to the evolution and maintenance of cooperation.
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Smallbone, Willow. "The impact of Major Histocompatibility Complex composition on fitness and life history traits of a vertebrate model, the guppy (Poecilia reticulata)." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/108113/.
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The Major Histocompatibility Complex (MHC) is a multi-gene family that includes most vertebrate immune genes. Life history traits have been associated with MHC allelic variation, including offspring survival, reproductive success, kin recognition, inbreeding avoidance, body mass gain, mate choice and parasite resistance. The studies reported in this thesis used laboratory and field investigations to identify differences in MHC genetic variation between truly wild, wild type and domesticated conspecifics and the implications of this for fitness, across the entire life history of a vertebrate, the guppy (Poecilia reticulata). Specifically, the effects of host inbreeding and domestication on parasite susceptibility are assessed in relation to MHC allelic and supertype composition. Laboratory studies showed that inbreeding and domestication lead to increased susceptibility to Gyrodactylus turnbulli, which was also linked to the presence of particular functional groups of MHC. A multi-site field sampling supported this finding; revealing that natural parasite communities reflected host MHC functional groups, as well as the river of origin. Truly wild fish had greater MHC genetic diversity than wild type (wild population maintained in the laboratory for ~ 3 years), which, in turn, were more genetically diverse than ornamental (domesticated) conspecifics. The accidental and deliberate release, into the wild, of domesticated fish is common. The release of infected and uninfected ornamental guppies into a wild type laboratory population increased parasite prevalence and abundance, due to the integration of a more susceptible individual into the social group. Mate preference is often linked to MHC similarity, whereby individuals select mates that are dissimilar or optimally similar at the MHC. The effects of sexual selection, MHC similarity and parasitism on mate choice, were assessed, indicating that a combination of factors are important in a female’s preference. Female guppies spent more time interacting with males with redder colouration and less MHC alleles in common. An experimental F1 generation revealed that offspring with parents sharing more MHC alleles and supertypes were more susceptible to parasitic infection. This research suggests that MHC functionality is at least as important as allelic and supertype diversity, with regards to individual fitness and life history traits.
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Borner, Karoline. "Influence of turbidity on social structure in guppies, Poecilia reticulata." Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17622.
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Umweltveränderungen kommen natürlicherweise vor und viele Spezies waren im Laufe ihrer Evolutionsgeschichte davon betroffen. Durch die Aktivitäten des Menschen jedoch finden diese in höherer Geschwindigkeit und größerem Umfang statt und stellen so für viele Spezies eine neue Herausforderung dar. Einen großen Einfluss auf die Umwelt nimmt der Mensch durch Verschmutzung, welche zu Veränderungen der Physiologie der Organismen und deren Verhalten führen und damit Einfluss auf die Populationsdynamik und letztendlich auf die Biodiversität haben kann. In meiner Dissertation untersuchte ich den Einfluss durch Bergbau ausgelöster Trübung auf das Verhalten und die soziale Struktur des Guppys. Er nutzt soziale Interaktionen für eine höhere Effizienz bei der Nahrungssuche und Räubervermeidung. Die Nutzung sei-nes dafür eingesetzten Sehsinns ist bei Trübung stark eingeschränkt. Ich untersuchte die Reaktion Trübung unerfahrener Fische aus Labor und Feld auf Trübung. Es zeigte sich, dass beide ihre sozialen Interaktionen in trübem Wasser verringerten. Eine zusätzliche Markow-Ketten-Analyse ergab aber auch, dass Laborfische Kontakte zu bestimmten In-dividuen der Gruppe verstärkten und Feldfische ihre initiierten Kontakte behielten. An-schließend studierte ich den Unterschied der sozialen Struktur Trübung erfahrener und - unerfahrener Fische. Trübung erfahrene Fische erhöhten die Gesamtzahl der Interaktio-nen, reduzierten jedoch die Anzahl der initiierten Kontakte im Gegensatz zu unerfahre-nen Fischen. Diese Strukturänderung, vermute ich, erhöht den Zusammenhalt und damit den In-formationsfluss im Schwarm. Die Ergebnisse von Folgeversuchen, nämlich der Erhalt der Paarungsanzahl und die effektivere Vermeidung einer Räuberattrappe bei Trübung er-fahrenen Fischen, unterstützen diese Vermutung. Die Arbeit zeigt, dass Guppys in der Lage sind, sich durch Änderung Ihrer sozialen Struktur an trübe Verhältnisse anzupas-sen. Dies könnte auch Einfluss auf ihre Populationsstruktur haben.Most species have been subjected to environmental changes during their evolutionary history. However, due to human activity, environmental changes are currently occurring at higher speeds and on a greater scale, presenting new challenges for many species. Pollution, as a major type of human-induced environmental change, may not only affect physiology but also behaviour, thereby affecting population dynamics and consequently biodiversity. The topic of my dissertation is the effect of turbidity from quarrying on the behaviour and social association pattern of the guppy (Poecilia reticulata). Turbidity impairs the fish’s ability to use visual cues during social interactions, which in turn helps increases efficiency of foraging and avoiding predators. I investigated the initial re-sponse of guppies to turbidity and subsequently tested whether turbidity-experienced vs turbidity-inexperienced populations differ in their social association patterns and how they cope with ecological challenges. Both lab-reared and wild-caught guppies that were inexperienced with turbidity reduced social associations in turbid water in con-trast to turbidity-experienced fish. A Markov chain analysis revealed that lab-reared guppies increased associations with particular neighbours. Similarly, wild-caught gup-pies maintained the number of initiated associations under turbid conditions. The in-crease in non-initiated associations suggests a stronger connectivity within the shoal, leading to higher information transmission in a poor visual environment. Additional results showed that this altered social structure enabled turbidity-experienced fish to maintain the frequency of mating attempts in turbidity and to avoid predation risk. This suggests that guppies have the ability to adjust to turbidity, but with major changes in their social structure, which might have an impact on population dynamics.
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Samuelsson, Ebba. "Beteendeförändringar till följd av exponering av läkemedlet Oxazepam : Förändringar i social tendens och aktivitet hos dvärgtandkarp (Heterandria formosa) och guppy (Poecilia reticulate)." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-182827.
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The aquatic environment is more or less constantly exposed to different types of pharmaceutical pollutants entering via treated waste water effluents. Benzodiazepines constitute one of many common pharmaceutical contaminants, which have been shown to impact fish behaviour in polluted freshwaters. The aim of this study was to assess whether one benzodiazepine (Oxazepam) affects the behaviour (activity and sociability) of guppies and least killifish. 50 fish of each species were studied in behaviour assays measuring the activity and sociability, where each individual was placed in separate aquariums and filmed in a special arena. One half of the individuals were then exposed to 10 μg/l Oxazepam in their respective tank for 7 days, after which the filming procedure were repeated for all fishes. The results show that least killifish significantly change their sociability by becoming less social after exposure to Oxazepam. However, their activity were not significantly affected. The result from guppies suggested a reduced sociability after exposure. Interpretation of the result were complicated by effects on the control group were guppies experienced a significantly reduced sociability during the treatment. This might be an effect of changes in habitat (lack of food, stress and environment) and/or an effect of Oxazepam. The results in the study show that Oxazepam reduces the sociability of least killifish and guppies.