Dissertations / Theses: 'Poecilia reticulata'

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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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2

Gasparini, Clelia. "Sexual conflict in the guppy, Poecilia reticulata." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426132.

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Sexual conflict is a widespread phenomenon in nature and it occurs over a wide range of decisions involving female-male interactions. This conflict drives the evolution of sexually antagonistic traits. Under a sexual conflict scenario, a trait that is beneficial to one sex is detrimental to the other driving the evolution of counteradaptation in a sort of ‘arm race’. In this process every evolutionary change in one sex is followed by a change in the opposite sex in order to minimize costs associated to the former. Mating frequency is one of the aspects of reproduction that could especially fuel sexual conflict and consequently sexually antagonistic coevolution because generally males have an optimal mating rate higher than females. My PhD thesis is aimed to study different aspects of sexual conflict using a small livebearing fish, Poecilia reticulata, as a model system. This species is particularly suitable for this purpose since sexual conflict is evident over mating rate, as revealed doubtless from the presence of high level of sexual harassment. I divided my researches into two main trends. First, I investigated costs and benefits of sexual conflict. Second, I focused on sexually antagonistic coevolution. Costs and benefits of sexual conflict. Estimate costs and benefits of sexual conflict shed new light on the evolution of female resistance that is assumed to evolve to minimize the costs associated to superfluous matings. However, a recent hypothesis argues that female resistance evolves as a way to screen the more successful male and therefore operate via indirect benefits mechanism. Results from a study of the effects of sexual harassment on female’s lifetime fecundity and on offspring’s quality revealed that do not support this latter hypothesis. I demonstrated only costs of sexual harassment on offspring both in daughters and in sons. Moreover, study on heritability of males’ traits influencing reproductive success both at pre- and postcopulatory level revealed scarce sire heritability that instead is a fundamental assumption of the hypothesis. The low heritability for males’ traits may be explained by adaptive phenotypic plasticity that has been investigated for sperm velocity. This demonstrated an adjustment in sperm velocity by males according to mating opportunities. Sexually antagonistic coevolution. My study of sexually antagonistic coevolution focuses on genitalia (male gonopodium and female oviduct). Gonopodial shape and dimension result important factors in determining the outcome of both consensual and coercive mating. Gonopodial length and shape resulted to be under sexual selection by female premating choice, with females mate more quickly with males possessing longer gonopodia with an enlarged shape. Gonopodium tip shape is revealed to be important in sperm transfer both in consensual and in forced matings. Another experiment demonstrated that females from low conflict population have minor control over sperm transfer in forced copulations by high conflict population males than relative counterparts. This result highlights the importance of male-female antagonistic coevolution in a sexual conflict scenario. An intraspecific study at population level corroborates this conclusion by providing evidence for a coevolutionary pattern between male and female concerning genitalia morphology. For this reason, genitalia might be the result of an evolutionary arm race between males and females in the struggle for control over mating rate and insemination success.
Il conflitto sessuale è un fenomeno ubiquitario in natura e interessa molte delle interazioni maschio-femmina portando alla evoluzione di caratteristiche sessuali antagonistiche. Per definizione, nel conflitto sessuale una caratteristica che avvantaggia un sesso comporta dei costi per l’altro sesso, per cui di conseguenza in quest’ultimo viene favorita la comparsa di controadattamenti in una sorta di ‘corsa agli armamenti’, in cui ogni cambiamento evoluzionistico che appare in un sesso è seguito da un cambiamento nell’altro sesso volto a minimizzarne i costi. La frequenza degli accoppiamenti è uno degli aspetti cruciali in cui il conflitto sessuale si manifesta e porta alla selezione sessuale antagonistica perché in generale i maschi hanno una frequenza ottimale di accoppiamenti che è maggiore di quella delle femmine. La mia tesi di dottorato ha avuto lo scopo di studiare alcuni aspetti del conflitto sessuale utilizzando Poecilia reticulata come modello di studio. Questa specie è particolarmente adatta per lo studio di queste tematiche, dal momento che è evidente la presenza del conflitto sessuale per quanto riguarda il numero di accoppiamenti, come si evince chiaramente dall’alto livello di sexual harassment (i continui tentativi di copula da parte dei maschi) subito dalle femmine. Le ricerche che ho effettuato per la mia tesi di dottorato si possono suddividere in due filoni. Primo: costi e benefici del conflitto sessuale. Secondo: coevoluzione sessuale antagonistica. Costi e benefici del conflitto sessuale. Studiare costi e benefici legati al conflitto sessuale è importante per capire l’evoluzione della resistenza femminile che si assume si sia evoluta con lo scopo di ridurre i costi legati agli accoppiamenti superflui. Di recente tuttavia si è avanzata l’ipotesi che la resistenza evolva attraverso il meccanismo dei benefici indiretti ottenuti selezionando i maschi più persistenti. Il primo lavoro ha riguardato lo studio degli effetti del sexual harassment sulla fecondità life-time delle femmine, ma anche degli effetti sulla prole. I risultati indicano che il costo del sexual harassment è visibile sulla prole, sia nei maschi che nelle femmine. Questi risultati non supportano perciò l’ipotesi che la resistenza femminile evolva attraverso l’acquisizione di benefici indiretti. Inoltre lo studio sull’ereditabilità di tratti maschili legati al successo riproduttivo ha dimostrato che tali caratteristiche sono poco ereditabili per via paterna, presupposto essenziale per questa ipotesi. La plasticità adattativa dei caratteri ne può spiegare la scarsa ereditabilità paterna riscontrata. Ho testato questa possibilità per un tratto legato al successo riproduttivo, la velocità spermatica, a seconda delle opportunità di accoppiamento percepite dal maschio. Si è dimostrato che i maschi sono in grado di modulare la velocità spermatica, confermando perciò la possibilità di un certo grado di plasticità che può spiegare i bassi valori di ereditabilità. Coevoluzione sessuale antagonistica. Lo studio della coevoluzione sessuale antagonistica si è concentrato sulla morfologia dei genitali, sia maschili che femminili. I risultati indicano che la morfologia dell’organo copulatore influenza il successo nel maschio sia negli accoppiamenti cooperativi che in quelli forzati. In particolare la dimensione e la forma generale dell’organo copulatore sono sessualmente selezionati attraverso la scelta femminile, e le femmine si accoppiano più velocemente con maschi dotati di gonopodi più lunghi e di forma allargata. Anche la forma della parte più distale del gonopodio risulta importante nel determinare il trasferimento degli spermi. La coevoluzione sessuale antagonistica prevede che quando una caratteristica modellata dal conflitto sessuale differisce tra popolazioni diverse, le femmine siano più resistenti ai maschi della propria popolazione, con cui si sono coevolute, rispetto a quelli di popolazioni diverse contro cui esse non hanno gli adattamenti necessari per resistere ad accoppiamenti non voluti. Questa previsione è stata confermata attraverso uno studio su maschi e femmine di popolazioni a diverso conflitto sessuale, in cui è stato dimostrato che femmine poste con maschi provenienti da una popolazione con un maggiore grado di conflitto sessuale hanno un minor controllo sul trasferimento degli spermi, rispetto a femmine che hanno avuto la possibilità di coevolvere con tali maschi. Infine uno studio comparativo fra popolazioni diverse indica l’esistenza di coevoluzione tra genitali maschili e femminili, che varia a seconda del grado di conflitto sessuale a cui le popolazioni sono soggette. Per cui l’evoluzione dei genitali sembra essere il risultato di una corsa agli armamenti tra maschi e femmine per il controllo della frequenza degli accoppiamenti e del successo di inseminazione.

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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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4

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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Serena, Giovanna. "Aspetti cognitivi della scelta sessuale in Poecilia reticulata." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3425817.

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It is traditionally assumed by models of decision making that, when alternative options are evaluated, the value assigned to each option is absolute and independent on the others available, implying that choice is rational. In contrast, rationality of choice is frequently violated, and such irrationality seems to be the result of use of simple heuristics that enable us to choose quickly between options differing in multiple attributes (comparative evaluation). Over the past three decades, there has been much work on ways that people use simple heuristics in problem-solving tasks. Animals, however, also need to make choices in complex decision environments, facing constrains in time, energy and computational-cognitive capacity. Recent studies have found biases in animal behaviour that are similar to the kinds reported in humans, indicating that similar heuristic strategies are used in different species in solving similar problems. It has been suggested that decision heuristics based on comparative evaluation might operate as mate choice mechanisms. In many species, females base their mate choice on the simultaneous evaluation of multiple signals. Females are often faced with a simultaneous choice between two or more males, and it is possible for them to make comparisons among those males. Mate choice is a complex cognitive process that involves the evaluation of multiple stimuli integrated into a behavioral decision. Yet the cognitive processes whereby prospective mates are evaluated have been ignored, with a few exceptions. The aim of this study was to investigate how animals search for and evaluate prospective mates throwing light on the cognitive mechanisms underlying mate choice. In the first part I analyzed how female guppies (Poecilia reticulata), a freshwater fish widely used in sexual selection studies, made mating decisions when combining different male attributes. The results show that the mating system of P. reticulata may facilitate comparative mate evaluation and suggest that it may have profound effects on male mating strategy. For example, the attractiveness of a male will depend on the context in which he is compared and males are therefore expected to choose the more favorable context in which to court the female. Moreover, I tested the prediction that males may exploit female cognitive constraints of comparative evaluation adjusting their mating strategy on the base of the relative quality of their competitors. The results indicate that male guppies actively select the most favourable social context in which their attractiveness will be maximized relative to that of surrounding males. It remains still unknown whether the rationality of choice may influence the strategies adopted by males as well.
Molti modelli economici presuppongono che, nello scegliere tra diverse opzioni, gli esseri umani si comportino in modo razionale. Tuttavia la realtà risulta essere più complessa e spesso nel valutare diverse opzioni si ricorre ad euristiche basate sulla valutazione comparativa che, contrariamente a quanto atteso, possono portare a decisioni irrazionali. Gli studiosi di etologia, negli ultimi anni, si sono chiesti se anche gli animali, di fronte a più opzioni che variano per due o più caratteri non correlati tra loro, adottino una valutazione comparativa e siano quindi soggetti agli stessi limiti di razionalità degli esseri umani dimostrando di utilizzare strategie di scelta simili. Nella scelta del partner sessuale un animale spesso si trova a scegliere tra diverse opzioni -i potenziali partner- che possono differire per due o più caratteri e la scelta deve essere effettuata in modo rapido ed efficiente. Si può ipotizzare quindi che una valutazione di tipo comparativo possa essersi evoluta anche nel contesto della scelta sessuale. Tuttavia la ricerca fino ad ora in questo campo si è occupata quasi esclusivamente di identificare quali caratteri maschili vengano preferiti dalle femmine e i vantaggi selettivi che comportano mentre i meccanismi cognitivi implicati nella scelta e gli effetti dei limiti cognitivi sulla fitness dei maschi e delle femmine stesse sono stati finora sostanzialmente ignorati, con pochissime eccezioni. La presente ricerca si proponeva di indagare se nell’ambito della scelta del partner sessuale, i limiti cognitivi che guidano la scelta in Poecilia reticulata, un piccolo pesce di acqua dolce, siano gli stessi osservati nella nostra specie. I risultati suggeriscono che le femmine opererebbero una scelta non razionale in accordo con quanto ci si attende dall’utilizzo di strategie di tipo comparativo. Inoltre in risposta al comportamento di scelta femminile è stato osservato che i maschi sembrerebbero a loro volta in grado di modificare la loro strategia corteggiando la femmina in prossimità di quei maschi rispetto ai quali, se confrontati, risulterebbero più attraenti per assicurarsi un aumento del successo riproduttivo. Ulteriori studi saranno necessari per comprendere se vi siano dei criteri di razionalità anche nella scelta maschile.

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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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Macario, Alessandro. "Ontogenetic environments and female mate choice in guppies, Poecilia reticulata." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/14288.

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Theoretical models of sexual selection assume that female mating preferences are fixed and variation found between individuals resulting solely from allelic variation at specific loci coding for sexual preferences. For the last decade, an increasing number of studies have demonstrated that individual phenotypic variation in preferences was common across a wide range of taxa and induced by the environmental context and the females’ condition. Further, developmental stages of life are crucial in the formation of behaviours in general and have proven to be determinant to learn sexual preferences in some species that dispense care for their young. However, very little studies have analysed how the early social and physical environments shape female mate choice in species that lack parental care. In this thesis, I used guppies (Poecilia reticulata), firstly, to investigate the influence of various aspects of the social environment provided by males during two ontogenetic phases. Secondly, I explored whether learned preferences in a foraging context during development could be transferred into a mating context. Considering the early social environment, I explored three distinctive features potentially displayed by males and that females might experience while growing. Females were reared with different values of a sexual trait not genetically preferred in the population (orange colour) and different values of a trait for which they had innate predisposition (total colour area). In both cases, females were exposed to the different treatments for the whole developmental period or for its later phase. My results indicated that females changed their sexual behaviours in response to both type of traits experienced, reversing sometimes their genetic preferences. Moreover, the timing of exposure seemed to be a key factor in the acquisition of preferences as females exposed only to the later part of development with different values of total colour didn’t rely anymore on colour patterns to discriminate among males. In a third body of experiment, I examined whether the overall phenotypic variance exhibited by males during whole development, independently of the values of a specific sexual cue, mediated female’s behaviours. In a context of high variance, female became choosier relatively to those experiencing less variance. As a response, males switched mating tactics and attempted more forced copulations. In its final part, my thesis searched for a link that might have arisen, owing to developmental conditions, between preferences using the same sensory modality in two behavioural contexts. Maturing females were given food that was associated to a certain colour and subsequently tested for both their coloured preference in a foraging and a sexual context. Although no foraging preference for the corresponding colour was detected, females that experienced a yellow stimulus preferred yellower males compared to females with other experiences. Taken together these results suggest that developmental conditions and especially the social environment play a pivotal role in the process of mate choice. Under some circumstances, learned mate preferences override genetically-based preferences highlighting the importance of non-genetic mechanisms. Accordingly, it is urgent to integrate in the study of sexual selection and reproductive isolation this dimension. In guppies, for instance, the effect of early social life might contribute to the maintenance of colour pattern polymorphism found in males.

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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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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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Chettri, Jiwan Kumar. "Tetrahymena sp. infection in guppies, Poecilia reticulata : immunization and treatment development /." [Sedeh Boker, Israel] : Ben-Gurion University of the Negev, 2008. http://aranne5.lib.ad.bgu.ac.il/others/ChettriJiwanKumar.pdf.

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Pires, Fernando Santiago. "Disrupção endócrina em testículos de Poecilia reticulata causada pelo herbicida glifosato." Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/3846.

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Xenobiotics pesticides are widely used in crops or even gardening throughout the world with purpose of a broad spectrum pest control, herbicides with glyphosate (N- phosphonomethyl glycine) as an active ingredient stands out amongst that group. The glyphosate (GLI) participates in a unique metabolic pathway during the synthesis of amino acids in plants, although, in animals it was thought to be harmless. However, literature indicates toxicity from commercial solutions, but few studies done with pure GLI. Moreover, to verify toxic potential of GLI, experiments done using Nuclear Magnetic Resonance (NMR). Furthermore, the test tanks were examined the presence of GLI for a period of 96 hours. It is because the GLI, during the metabolism of prokaryotes, converts to Aminomethylphosphonic acid (AMPA). The results showed the absence of AMPA at 96 hours of exposure, whereas, any changes were attributed to GLI in these animals. Primarily, the dose of CL50-96h for the experimental animal, Poecilia reticulata (guppy), was determined. It estimated at 68.51 ± 2.2 mg/L for males and at 70.56 ± 2.96 mg/L for females. The lethal dose calculated according to the recommended guidelines from the Organisation for Economic Co-operation and Development (OECD). During these tests the animals in the experimental group (EG) exposed at concentrations of 50, 55, 60.5, 66.5 and 73.2 mg/L showed swimming changes (17.5% - lethargy, 11.1 % - irregular swimming and 45.9% - hypoxia). Respiratory changes (8.3% - swam to the tank surface, 1.8% - hypo oxygenated) and changes in color pattern, such as loss of intensity of the hues orange, red, blue, and assuming a dull coloration (14.3%) in all EG. Subsequently, male’s guppy treated with sublethal doses of pure GLI in concentrations of 17.13 mg/L (25% CL50), 34.26 mg/L (50% CL50) and 51.39 mg/L (75% CL50) as per 203 guidelines of the OECD. After euthanasia, by descerebration, the male animals were dissected and the testicles fixed in buffered paraformaldehyde, sectioned in 2.0 μm slices by an ultramicrotome and placed in histoResin®. The sections stained with hematoxylin and toluidine blue/Floxine B, then photographed under light microscope. The program Image-Pro Plus provided the images, which analyzed by the program Statistica 7.0. Consequently, the data reviewed that GLI has toxic potential. It has the potential to: cause testicular regression - morphometric measures decrease, reduce the number of the spermatic compartments, reduce the gonad index (Igs) and promote histopathology which may lead to reduction or loss of function. Thus, characterizing a process of demasculinization, which indicates endocrine disruption.
Agrotóxicos são xenobióticos utilizados largamente nos lavouras ou mesmo em jardinagem em todo mundo para o controle de pragas agrícolas, e entre eles destacam-se os herbicidas a base de Glifosato (N-fosfonometil-glicina). O Glifosato (GLI) participa de uma rota metabólica exclusiva na síntese de aminoácidos nas plantas e foi considerado inofensivo aos animais. Contudo, há relatos na literatura que indicam a toxicidade das soluções comerciais à base de GLI, mas poucos abordam a atividade do GLI puro. Dessa maneira, para se verificar o potencial toxico do GLI, primeiramente, experimentos com Ressonância Magnética Nuclear (RMN) foram realizados para verificar a presença de GLI nos aquários testes pelo tempo de 96h. Isso foi feito porque o GLI pode ser convertido a ácido aminometil fosfônico (AMPA) pelo metabolismo de procariotos. Os resultados demonstraram ausência de AMPA até 96h de exposição e dessa forma foi atribuído ao GLI qualquer alteração presente nos animais testes. Depois foi determinado o valor da CL50-96h para o animal experimental Poecilia reticulata (guarú). Essa foi estimada em 68,51 ± 2,2 mg/L para machos e 70,56 ± 2,96 mg/L para fêmeas. Os testes de toxicidade letal para o cálculo da CL50-96h foram feitos de acordo com as recomendações do guia 203 da Organização para cooperação e desenvolvimento do comércio (OECD). Durante esses testes os animais do grupo experimental (GE) expostos nas concentrações de 50; 55; 60,5; 66,5 e 73,2 mg/L apresentaram alterações comportamentais como distúrbios natatórios (17,5% – letargia; 11,1% – natação irregular e 45,9% – hipoatividade), respiratórios (8,3% – nado na superfície do aquário; 1,8% – hipóxia) e alterações no padrão da coloração (14,3%) como perda da intensidade das matizes laranja, vermelha e azul e dos tons acetinados em todos os GE. Posteriormente guarús machos foram tratados com doses subletais do GLI puro nas concentrações de 17,13 mg/L (25% da CL50), 34,26 mg/L (50% da CL50) e de 51,39 mg/L (75% da CL50) conforme o guia 203 da OECD. Após a eutanásia por descerebração, os animais foram dissecados e os testículos foram fixados em paraformaldeído tamponado, inclusos em historresina e seccionados a 2,0 μm em ultramicrótomo. Os cortes foram corados com Azul de toluidina e hematoxilina/floxina e posteriormente fotografados em fotomicroscópio. As imagens forneceram dados obtidos pelo programa Image Pro-Plus que foram analisados pelo programa Statistica 7.0. Foi demonstrado que o GLI apresenta potencial tóxico para o guarú por causar regressão testicular pela redução das medidas morfométricas, redução do número de compartimentos espermáticos, redução do Índice gonadossomático (Igs) e por promover histopatologias que podem levar a diminuição ou a perda da funcionalidade do testículo. Tal processo caracteriza a desmasculinização, um indicativo de disrupção endócrina.

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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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The 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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Cunha, Larissa da. "Produção de guppys (Poecilia reticulata) em sistemas de cultivo com bioflocos." Universidade Federal do Pampa, 2016. http://dspace.unipampa.edu.br:8080/xmlui/handle/riu/495.

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Com o objetivo de avaliar a possibilidade da produção de guppy (Poecilia reticulata) em sistema com bioflocos, dois experimentos foram desenvolvidos no Laboratório de Aquariofilia da Universidade Federal do Pampa, Uruguaiana, RS. Os experimentos foram realizados em delineamento inteiramente casualizado e os resultados foram submetidos à análise de variância ANOVA e à comparação das médias pelo teste de Tukey (5%). O primeiro estudo objetivou avaliar o desempenho produtivo de juvenis de guppys (comprimento total inicial de 18,06 ± 0,30 mm e peso inicial de 0,056 ± 0,003 g), produzidos em sistema de bioflocos com diferentes taxas de alimentação, comparando-os com um sistema de produção em água clara. Foram avaliados quatro tratamentos, com quatro repetições: sistema de água clara (controle) com oferta de ração a 3% do peso vivo (SAC), sistema enriquecido com bioflocos sem a oferta de ração (BFT0), sistema enriquecido com bioflocos com oferta de ração a 1,5% do peso vivo (BFT1.5) e sistema enriquecido com bioflocos com oferta de ração a 3% do peso vivo (BFT3). Os parâmetros de qualidade da água foram monitorados semanalmente. Os resultados demonstraram que os tratamentos enriquecidos com bioflocos apresentaram melhor controle dos níveis de amônia da água. Ao final do período experimental os animais dos tratamentos SAC, BFT0 e BFT1.5 não apresentaram diferenças significativas entre si, para as variáveis CT, CP, peso e TCE. No entanto, todos os tratamentos foram inferiores ao tratamento BFT3 em todas as variáveis de desempenho analisadas. Em contrapartida, a CAA não apresentou diferença significativa entre os tratamentos BFT1.5 e BFT3, sendo o tratamento SAC mais elevado que os demais. A sobrevivência foi superior nos tratamentos com oferta de ração. O segundo estudo objetivou avaliar o desempenho produtivo de juvenis de guppys (comprimento total inicial 12,10 ± 0,13 mm e peso inicial 0,015 ± 0,000 g) submetidos à ciclos de restrição alimentar e realimentação em sistema de bioflocos. Foram avaliados três tratamentos, com seis repetições: sistema de água clara (controle) com alimentação diária (SAC), sistema enriquecido com bioflocos com alimentação durante cinco dias seguidos de dois dias de restrição de alimento (BFTR) e sistema enriquecido com bioflocos com alimentação diária (BFT). Os animais foram produzidos até entrarem no período reprodutivo e os parâmetros de qualidade da água foram mensurados semanalmente. Os resultados demonstram que os sistemas de cultivo BFT com e sem restrição alimentar apresentaram melhor controle dos níveis de nitrito em comparação ao sistema em água clara. Os animais produzidos nos sistemas BFT com e sem restrição alimentar atingiram o período reprodutivo na metade do tempo necessário para os animais produzidos em sistema de água clara, assim como apresentaram melhor desempenho produtivo (CT, CP, Peso, CAA e TCE). Os resultados sugerem que o sistema BFT pode ser empregado no cultivo de guppys, servindo como fonte alimentar aos organismos cultivados, melhorando o desempenho produtivo e os parâmetros de qualidade da água.
In order to assess the feasibility of guppy (Poecilia reticulata) production in system with bioflocs, two experiments were developed in Aquariofilia Laboratory of Federal University of Pampa, Uruguaiana, RS. The experiments were conducted in a completely randomized design and the results were submitted to analysis of variance ANOVA and the comparison of means by Tukey test (5%). The first study aimed to evaluate the performance of juvenile guppys (initial total length of 18.06 ± 0.30 mm and initial weight 0.056 ± 0.003 g), produced in biofloc system with different feed rates, comparing to a production system in clear water. Four treatments were evaluated with four replicates: clear water (control) system with feed supply 3% of body weight (CWS), biofloc technology system without the supply of feed (BFT0), biofloc technology system with feed supply 1.5% of body weight (BFT1.5) and biofloc technology system with feed supply 3% of body weight (BFT3). Water quality parameters were monitored weekly. The results showed that biofloc treatments showed better control of water ammonia levels. At the end of experiment the animals CWS, BFT and BFT1.5 showed no significant differences, for TL, SL, weight and SGR. However, all treatments were lower than BFT3 treatment in all three performance variables. In contrast, the FCR had no significant difference between the BFT1.5 and BFT3 treatments, being CWS the highest treatment. Survival was superior in the treatments with supply of feed. The second study aimed to evaluate the performance of juvenile guppys (initial total length 12.10 ± 0.13 mm and initial weight 0.015 ± 0.000 g) submitted to food restriction and refeeding cycles in biofloc system. Three treatments were evaluated, with six replications: clear water (control) system with daily food (CWS), biofloc technology system with food for five days followed by two days of food restriction (BFTR) and biofloc technology system with daily food (BFT). The animals were maintained until they enter the reproductive period and water quality parameters were measured weekly. The results demonstrate that the BFT cultivation systems with and without feed restriction showed better control of nitrite levels compared to the system in clear water. Animals produced in BFT systems with and without food restriction reached the reproductive period at half time required for animals produced in clear water system, and showed better growth performance (TL, SL, Weight, FCR and SGW). These results suggest that BFT system can be employed in guppys farming, serving as food source for organisms grown, improving growth performance and water quality parameters.

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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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Miranda, Edmund Richard. "Morphological constraints on life history evolution in Poecilia reticulata (Cyprinodontiformes: poeciliinae)." CSUSB ScholarWorks, 1999. https://scholarworks.lib.csusb.edu/etd-project/1722.

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Walz, Julia C. "Behavioral and hormonal flexibility across light environments in guppies (Poecilia reticulata)." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1290.

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Behavior may be dramatically influenced by changing environments, and differences in light intensity environments may have important behavioral consequences. One approach to understanding changes in behavior is by studying behavioral syndromes, suites of correlated behaviors reflecting between individual consistencies in behavior expressed within a behavioral situation (e.g., correlations between antipredator behaviors in different habitats), or across behavioral contexts (e.g., correlations among feeding, antipredator, or mating behavior) (Sih et al. 2004a). Guppies (Poecilia reticulata) provide a great model system to study behavior. Guppies are small, freshwater tropical fish that inhabit still pools in swift-flowing streams, and the backwaters of small rivers in mountain forest areas of Trinidad (Houde 1997; Magurran 2005). In this study I attempted to answer the following questions using three low predation populations of guppies : 1) Do guppies display a behavioral syndrome for aggression and/or courtship across light situations?; 2) Are there mean level changes in aggression or courtship across light situations?; 3) Are mean level changes influenced by differing social environments that include or lack sexually receptive females?; 4) Are there correlations between behavior and the androgen hormones testosterone and 11-ketotestosterone?; 5) Are there correlations between behavior and the stress hormone cortisol?; 6) Are there mean level changes in hormone release rates across light environments?; and 7) Is flexibility in hormone release rates influenced by social environments that include or lack sexually receptive females? Guppies exhibit behavioral syndromes for both aggression and courtship. Furthermore, guppies exhibit behavioral flexibility for both aggression and courtship, but only in social environments that include sexually receptive females. I found no correlations between behavior and androgen hormones. I also did not find any correlations between behavior and the stress hormone cortisol. Furthermore, I did not find any mean level changes in hormone release rates across light environments. Interestingly, cortisol levels were higher in social environments in which sexually receptive females were absent. Many studies have looked at how the environment influences courtship behavior in guppies, especially employing high predation populations, but few studies have examined aggressive behavior or behavior in general with low predation populations. Furthermore, few studies have determined the role social environments play, and how hormones may interact with behavior. This study is important because it helps illuminate how low predation populations deal with changes in light intensity environments, and adds to what we understand about guppy behavior in general.

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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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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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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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van, Wijk Serinde Joy. "Fisheries-induced evolution : a genetic approach using selection experiments on Poecilia reticulata." Thesis, Bangor University, 2011. https://research.bangor.ac.uk/portal/en/theses/fisheriesinduced-evolution--a-genetic-approach-using-selection-experiments-on-poecilia-reticulata(adaa7358-b125-4c25-af39-b8e269d77d75).html.

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Lucon, Xiccato Tyrone. "Evaluating guppy, Poecilia reticulata, as a model for sex differences in cognition." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424369.

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Whether cognitive differences exist between men and women is a question probably as old as experimental psychology though still highly controversial. Despite the large number investigations, sex differences in performance emerge only in a few cases, such as in visuo-spatial or verbal abilities. However, it is not clear if these differences are biological or due to cultural influences, possibly because we know very little about their underlying mechanisms and evolutionary causes. Sex differences in cognition have been investigated also in few other species, such as monkeys, rodents and chickens. Rodents, in particular, represent a powerful model in the field of spatial abilities, allowing, among the others, complex hormonal manipulations, drugs tests and between-species comparative studies. Recent years have seen a massive increase in the use of fish as models for cognitive research, at the point that fish are predicted to replace classical vertebrates models soon. The existence of cognitive sex differences in fish has not been investigated. Paradoxically, experimenters quite often use indiscriminately fish of both sexes in their experiments, introducing a confound if cognitive sex differences exist. In this thesis, I studied cognitive sex differences in the guppy, Poecilia reticulata, one of the most studied species in behavioural and cognitive research. Male and female guppies are characterized by considerable differences in ecology and behaviour. I compared the performance of males and females in a wide range of cognitive tasks, including visual discrimination learning, novel object recognition, rule learning, reversal learning, spatial navigation, spatial learning and quantity discrimination. Male and female guppies showed similar abilities in solving most of the tasks, with only two exceptions. In a reversal learning task, guppies were initially trained to obtain food by choosing a predetermined colour between two options, a task that the two sexes learned equally well; then, the reward contingency was reversed and subjects had to inhibit the learned preference to select the other stimulus. Females quickly started to choose the new rewarded colour while males persisted longer in selecting the previously rewarded colour. The second difference emerged in a quantity discrimination task. Guppies were required to select the larger between two groups of conspecifics, following a natural tendency of social fish to stay in larger shoals to reduce predation risks. At the beginning of the experiment, females were much better than males at solving the task; this difference vanished after some minutes. The two observed sex differences are possibly the result of differential action of natural selection on the two sexes. Indeed, male guppies are thought to undergo selection for high persistence that helps in courting females intensively; females are likely to undergo strong selection for predator avoidance skills as predators preferentially target females. The absence of sex differences in the other cognitive abilities can be due to the absence of sex differences in selective pressures, or, alternatively, to the existence of constraints that prevent differentiation. In many of the tasks in which males and females obtained similar scores, they were nonetheless observed to behave quite differently. In visual discrimination tasks and in a spatial learning task, males were faster than females in deciding which option to choose, suggesting greater impulsivity in males. In the novel object recognition task, males and females expressed equal ability in discriminating the two objects, yet males explored the novel object at the beginning of the test, females some time afterwards. In the spatial navigation task, males persisted longer than females in trying to reach a target behind a transparent barrier. The general lack of sex differences in cognitive abilities in guppies aligns with the scarce evidence of sex differences in cognitive abilities in mammals. However, I provided evidence that minor differences in performance, such as in persistence, impulsivity and exploratory tendency, typically found in mammals and birds are widespread in fish as well.
L’esistenza di differenze sessuali nella cognizione è uno dei temi più studiati fin dalla nascita della psicologia sperimentale, ma tuttora uno dei più dibattuti. Nonostante le innumerevoli ricerche effettuate, sono state rilevate differenze sessuali solamente in pochissimi compiti, come quelli che misurano le abilità verbali e le abilità spaziali. Non è del tutto chiaro però se queste differenze nella prestazione siano dovute a differenze biologiche tra i due sessi oppure a differenze culturali. In parte questo è dovuto al fatto non se ne conoscono i meccanismi prossimi e neppure le cause evolutive. Sono state rilevate differenze sessuali nella cognizione anche in un limitato numero di altre specie. In particolare, i roditori sono utilizzati come modello per lo studio delle differenze sessuali nella abilità spaziali, specialmente nelle ricerche che richiedono manipolazioni ormonali, comparazione tra specie, o sperimentazioni farmacologiche. Negli ultimi anni, i pesci stanno gradualmente sostituendo roditori e altri animali modello nella ricerca in ambito cognitivo. Tuttavia, l’esistenza di differenze sessuali nella cognizione nei pesci non è ancora stata studiata. Paradossalmente, in alcuni esperimenti vengono utilizzati indiscriminatamente pesci di entrambi i sessi, introducendo un potenziale fattore confondente. In questa tesi ho studiato le differenze sessuali nella cognizione in Poecilia reticulata. Si tratta di una specie molto usata nelle ricerche cognitive, in cui maschi e femmine differiscono sostanzialmente per morfologia, ecologia, e comportamento. Ho comparato maschi e femmine di P. reticulata in diversi compiti cognitivi, tra cui apprendimento di discriminazioni visive, memoria, apprendimento di regole astratte, orientamento, apprendimento spaziale, e discriminazione di quantità. I maschi e le femmine di P. reticulata hanno ottenuto prestazioni simili nella maggior parte degli esperimenti, con solo due eccezioni. In un esperimento di reversal learning, i soggetti sono stati dapprima addestrati ad ottenere un rinforzo alimentare scegliendo un predeterminato colore tra due opzioni, un compito che entrambi i sessi hanno appreso con la stessa efficienza. Successivamente, il colore rinforzato è stato invertito e i soggetti dovevano quindi inibire la tendenza a scegliere il colore precedentemente rinforzato e selezionare il colore che precedentemente non era rinforzato. Le femmine si sono adattate velocemente all’inversione della contingenza del rinforzo, mentre i maschi hanno persistito molto più a lungo a scegliere il colore precedentemente rinforzato. La seconda differenza sessuale è emersa in un compito di discriminazione di quantità. In questo esperimento, i soggetti dovevano discriminare il gruppo sociale più numeroso tra due opzioni, seguendo la tendenza spontanea di questa specie a unirsi al gruppo più numeroso per diluire il rischio individuale di predazione. Le femmine riconoscevano il gruppo maggiore fin dall’inizio dell’esperimento, mentre i maschi solo alcuni minuti dopo. Queste due differenze sessuali osservate sono probabilmente dovute a forti pressioni selettive che differiscono sostanzialmente nei due sessi. Si crede infatti che i maschi di P. reticulata siano selezionati per esprimere comportamenti persistenti che sono d’aiuto durante il corteggiamento. Le femmine di P. reticulata, invece, sono il bersaglio preferito dai predatori e si ritiene siano selezionate per quei tratti, come la discriminazione della numerosità del gruppo sociale, che aiutano nella difesa dai predatori. In molti degli esperimenti, nonostante la prestazione praticamente uguale, maschi e femmine hanno però mostrato di comportarsi in modo differente. In compiti di apprendimento di discriminazioni visive e spaziali i maschi erano molto più veloci nello scegliere una delle due opzioni, suggerendo una maggiore impulsività in questo sesso. In un compito di memoria, entrambi i sessi mostravano comportamento esploratorio rivolto verso un nuovo oggetto, tuttavia i maschi lo esprimevano all’inizio del esperimento mentre le femmine diversi minuti dopo. In un compito di navigazione spaziale, i maschi persistevano più a lungo delle femmine nel tentare di passare attraverso una barriera trasparente per raggiungere un gruppo di conspecifici retrostante. La generale mancanza di differenze sessuali nelle abilità cognitive in P. reticulata è sorprendente vista la diffusa presenza di differenze sessuali in ecologia e comportamento in questa specie, ma è tuttavia in accordo con la scarsità di differenze sessuali rilevate nei mammiferi. Tuttavia, questa tesi ha dimostrato come altre differenze minori nella prestazione nei compiti cognitivi che generalmente si osservano in mammiferi e uccelli, come le differenze comportamentali tra i sessi in persistenza, impulsività ed esplorazione, sono diffusi anche nei pesci.

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26

Gonçalves, Bruno Bastos [UNESP]. "Efeitos de herbicida à base de glifosato em aspectos reprodutivos de guppies (Poecilia reticulata)." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/151033.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
A população humana cresce em proporções maiores que a produção de alimentos. Nesse cenário, a agricultura potencializa este cultivo por meio do uso de defensivos agrícolas, como por exemplo, herbicidas à base de glifosato (HBG). Entretanto, tais produtos possuem vários efeitos adversos em organismos não-alvos, como peixes. Estudos apontam danos em tecidos e em material genético de peixes, porém, não há estudos sobre o comportamento reprodutivo dessa espécie quando expostas a concentrações permitidas por lei. Assim, testamos os efeitos de HBG na seleção sexual de parceiros e na qualidade espermática de machos de Poecilia reticulata. Para isso, avaliamos o comportamento sexual, o interesse sexual, a qualidade espermática e a receptividade das fêmeas a machos expostos a 2 concentrações de HBG (50 e 100 μg/L) por 48 horas. Para avaliar a escolha de parceiros, utilizamos o método de escolhas dicotômicas e análise de múltiplas escolhas. Já para análise da qualidade espermática, avaliamos a morfologia, a viabilidade, a concentração e a motilidade dos espermatozoides. Nossos resultados indicam que machos não expostos ao HBG diminuem a exibição para fêmeas expostas ao HBG e evitam copular com fêmeas expostas à concentração de 100μg/L. Além disso, fêmeas expostas ao HBG são menos receptivas à cópula. O HBG afetou a morfologia dos espermatozoides, onde machos expostos a 50μg/L apresentaram maior quantidade de células com danos primários. Porém, não afetou a viabilidade, concentração e motilidade dos espermatozoides. Nossos dados indicam que concentrações ambientalmente relevantes de HBG podem afetar o comportamento reprodutivo e a qualidade espermática de peixes.
Human population grows in bigger proportions then food production worldwide. To solve this problem, increase food production is required. Agriculture has potentialized food production through pesticides usage. Besides that, GMO's increase production and usage of glyphosate based herbicide (HBG), since this product does not affect GMO’s. HBG's have many side effects on non-target animals, such as fishes. Many studies demonstrated damage in a lot of tissues and DNA. However, effects on behavior and even in concentrations allowed by law have not been studies. We aim to assess the effects of a GHB on physiological and behavioral reproductive features of Poecilia reticulata as male sexual behavior, sexual interest, sperm quality and female receptivity. We used dichotomous and multiple-choice arenas for mate choice and viability, concentration, motility and morphology to assess sperm quality. HBG decrease female receptivity, affects male interest on perform displays and mate attempt with females exposed to 100µg/L. HBG also affected sperm quality of males exposed to 50µg/L concentration. Despite this, we did not find any effect on viability, concentration and motility of sperm cells of exposed males to any concentration. We conclude that HBG affects female receptivity, and, in turn, it affects sexual male effort, reducing display and mate attempt rate. Our data shows that HBG, even in environment relevant concentrations, can affect reproductive behavior and sperm quality. We show here the necessity to assess with more caution the toxicology of pollutants and its effects, as the law that regulates it.
CNPq: 147399/2013-0

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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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The 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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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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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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The 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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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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Araújo, Cristiano Venícius de Matos. "Avaliação ecotoxicológica da lagoa de Dunas (Camaçari, Bahia, Brasil)." reponame:Repositório Institucional da UFBA, 2012. http://www.repositorio.ufba.br/ri/handle/ri/5543.

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Capes e Millennium Inorganics Chemicals
Buscou-se avaliar o potencial tóxico da redução do pH sobre o peixe Poecilia reticulata,através de ensaios de ecotoxicidade agudos, bem como avaliar como um aumento no pH da água da lagoa pode influenciar na sua toxicidade. Amostras de água da Lagoa de Dunas foram coletadas e testadas com os seguintes tratamentos: água in natura (pH ± 3,0) e amostras com pH alterados para 3,5, 3,8, 4,0, 4,3, 4,6, 5,0, 5,5, 6,0 e 6,5. Foram usadas ainda amostras da água de cultivo dos peixes, cujos valores de pH foram reduzidos para o mesmo da Lagoa de Dunas. Os resultados médios e respectivos intervalos de confiança do 96 h-LT50 da Lagoa de Dunas e da água de cultivo com pH reduzido foram 1,37 (1,18-1,56)h, e 1,04 (0,73-1,34) h, respectivamente, sem diferença estatística significativa (p ≥ 0,05).Para as amostras da Lagoa de Dunas com valores de pH elevados houve uma redução significativa da toxicidade, não sendo detectada toxicidade a partir do pH 6,0. Estes resultados demonstram que, nestas condições, o pH é o fator limitante para P. reticulata.
Salvador, Bahia

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Zajitschek, Susanne Biological Earth &amp 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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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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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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Gonçalves, Bruno Bastos. "Efeitos de herbicida à base de glifosato em aspectos reprodutivos de guppies (Poecilia reticulata) /." Jaboticabal, 2017. http://hdl.handle.net/11449/151033.

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

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Potts, Warren Mason. "A nutritional evaluation of effluent grown algae and zooplakton as feed ingredients for Xiphohorous helleri, Poecilia reticulata and Poecilia velifera (Pisces : Poeciliidae)." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005151.

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The aim of this study was to evaluate the nutritional value of algae and zooplankton grown in an algal integrated ponding system for poeciliids. The available information on the nutritional requirements of poeciliids was compared with a proximate analysis of the algae and zooplankton. The effluent grown algae and zooplankton had a crude protein value of 41.47 ± 0.2% and 36.84 ± 0.3%, a lipid content of 4.8 ±. 0.4% and 11.1 ± 0.8% and a carbohydrate content of 35.13 ± 0.8% and 31.06 ± 0.6% respectively. These values compared favourably with those of the known nutritional requirements of poeciliids. To test if the nutritional value of the algae and zooplankton in the AlPS was constant, the species composition of the algae and the crude protein content of the algae and zooplankton in the high rate oxidation ponds were measured monthly and bi-weekly for a year respectively. The species composition remained fairly stable for the duration of the experiment and the average protein composition of the algae and zooplankton was 43.4 ± 4.4% and 38.6 ±2.8% respectively. This indicated that the algae and zooplankton in the AlPS provided high protein biomass through the year. The quality of the effluent grown algal and zooplankton biomass was evaluated by analysing their amino acid composition and comparing it with the amino acid composition of the body tissue of X. helleri. With respect to the amino acid composition of the body tissue of X. helleri, the amino acid profile of the algae had a 69% and the zooplankton a 63% similarity. The quality of the pure algal and zooplankton protein was also tested biologically, by feeding them directly to poeciliids during a ten week growth trial. The algae and zooplankton diets did not result in adequate growth compared to poeciliids which were fed a formulated control diet. The initial growth trial also evaluated the effect of processing on the chemical composition of the algae and its biological effect on fish fed with it. There were no significant differences in the chemical composition of fresh and sun dried algae and this was reflected in the growth rates of the fish which did not differ significantly. Freeze dried algae had a lower crude protein content than fresh and sun dried algae and a poorer amino acid composition. Fish fed freeze dried algae exhibited poorer growth and survival in comparison to the other treatments. The gut transit times of X. helleri and the gastric evacuation times of poeciliids were determined using colour dyes incorporated in the diet and by sacrificing fish at predetermined intervals after feeding respectively. The gut transit time of X. helleri fed a sun dried algal diet and a formulated diet was 225 ± 8.55 minutes and 261.93 ± 10.86 minutes respectively. The gastric evacuation times of X. helleri, P. reticu/ata and P. velifera were 7, 9 and 8 hours respectively. Since the maximum amount of food in the hindgut after feeding was detemined to be 3, 5 and 3 hours in X. helleri, P. reticulata and P. velifera respectively, fish were sacrificed at these times in the digestibility study. The digestibility of sun dried algae was determined using 1 % chromic oxide as an internal marker in the algae. The apparent crude protein digestibility of sun dried effluent grown algae ranged from 65%-75% in the three poeciliid species. Based on the results of the chemical and biological analysis of the algae and zooplankton, conventional diets incorporating algae at 5% and 20% protein inclusion levels were formulated. These diets and a treatment in which zooplankton, reared in the AlPS were fed as a dietary supplement to a formulated diet were fed to poeciliids for twelve weeks. No significant differences in the growth of poeciliids fed any of the test diets were observed. It was concluded that the algae could be incorporated into poeciliid formulated diets up to level of 20% protein inclusion without any negative effect on the growth of the fish. The chemical and biological evaluation of the algae suggested that it had a similar nutritional quality to soyabean meal. Poeciliid growth was not enhanced with a zooplankton supplement, however a possible low feeding rate by poeciliids on the zooplankton as a result of their small size may have affected the result. The colour enhancement potential of effluent grown algae and zooplankton was evaluated biologically in ten and twelve week growth trials using visual observation (31 people) and by using a chromameter. While pure, sun dried algae significantly enhanced the colour of P. reticulata, no significant differences in the colour of poeciliids were observed or recorded when fish were fed diets incorporating sun dried algae up to levels of 20% protein inclusion. The effect of effluent grown algae and zooplankton on poeciliid health was also tested biologically in the ten and twelve week growth trials. The high mortalities (75%-84%) recorded for X. hel/eri when fed the pure algal and zooplankton diets were considered to be as a result of the nutritional inadequacy of the diets since there were significantly less mortalities in fish fed the formulated control diet and 63% of the fish that died during the course of the trial were emaciated. In addition, fewer mortalities (10%-40%) were recorded in X. hel/eri fed the nutritionally adequate formulated diets in the twelve week growth trial. No symptoms of disease were recorded in the twelve week growth trial and the algae was considered to have no toxicological or pathological effects on poeciliids. Centrifugation, sand filtration, sedimentation, microstraining and biological harvest were evaluated as methods of small scale algal harvest from the high rate oxidation ponds. Algae could be harvested most efficiently with little associated labour by sedimentation (without flocculating agents) and by microstraining with 60IJm mesh. Effluent grown algae can replace conventional feed ingredients up to a level of 20% protein inclusion without negatively effecting the growth, colour, health or survival of poeciliids.

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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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Rodgers, Brandon. "Poecilia reticulata predation on Aedes aegypti larvae : effects of predator body size and vegetation density." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100206.

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In this study, predation efficiency of three guppy ( Poecilia reticulata) size classes was evaluated at various vegetation densities in a series of circular aquaria containing plastic plants closely resembling Ceratophyllum demersum. The effect of vegetation density was most apparent among large fish where predation efficiency greatly diminished from 12.35 mosquito larvae (Aedes aegypti) to 4.68 as vegetation densities rose from 3 to 19 plants/700 cm2. Over that same range of increasing vegetation densities, predation among small fish remained unchanged, whereas among fish of intermediate size predation declined significantly but less precipitously than for large individuals. When presented with a choice between second and fourth mosquito larvae, small fish preferred to prey on second instars, whereas large fish preferred fourth instar larvae. Fish of intermediate size did not show a statistically significant preference. The functional response of fish to increasing prey densities, as measured over a 12-h period, was of Type III.

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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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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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Tapia, Vilchez Fernando Jesús. "Interacción de temperatura y Clorpirifos (PYRINEX ®) sobre la estabilidad genética de Poecilia reticulata “GUPI”." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2017. https://hdl.handle.net/20.500.12672/7159.

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Clorpirifos (Pyrinex ®) es un insecticida organofosforado de amplio uso en la agricultura, la extensión de su uso en el Perú no está documentada, sin embargo, se estima que podría ser parte de una variedad de tóxicos presentes en el agua y que tendrían efectos deletéreos sobre poblaciones locales de peces. Interacciones de la temperatura (17, 25 y 30 °C) fueron evaluadas, en presencia de concentraciones sub-letales de Clorpirifos (0, 0.005, 0.010, 0.015, 0.020 y 0.025 mg/L) enfocadas en estabilidad genética expresada en términos de frecuencia de micronúcleos y otras anormalidades nucleares sobre Poecilia reticulata “gupi”. Los resultados muestran que las interacciones fueron significativas (p = 0.001), la frecuencia de anormalidades nucleares no difiere entre grupos control independientemente de la temperatura, se observaron incrementos significativos con la concentración (p = 0.001) y la temperatura (p = 0.001), al mismo tiempo se reportó una CL50 para Clorpirifos a 17°C de 0.015 mg/L, no se reportó mortalidad a 25 y 30°C. Se sugiere que la toxicidad varía en sus mecanismos de acción según las interacciones: (1) a temperaturas altas (25 y 30°C) la genotoxicidad se incrementa, sin mortalidad; y (2) a temperaturas bajas (17°C), se reducen los procesos de formación de anormalidades nucleares, sin embargo, la mortalidad se ve aumentada significativamente debido a que Clorpirifos reduce umbral de tolerancia de temperatura de P. reticulata. Se confirma el alto riesgo de Clorpirifos y sus interacciones con la temperatura, por lo que se sugiere que los ensayos de ecotoxicidad deben tomar en consideración la temperatura del ambiente y no sólo la temperatura óptima de la especie en evaluación lo cual conllevaría a una sub- o sobre estimación de la toxicidad. Estas interacciones de contaminantes y medio ambiente (en especial la temperatura) deben ser considerados en el contexto de eventos climáticos extremos, cambio climático y de cambios en la actividad agrícola e industrial.
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Frello, Célia Perin. "Avaliação da toxicidade aguda do agrotóxico carbofuran utilizando reativos biológicos :: poecilia reticulata e daphnia magna /." Florianópolis, SC, 1998. http://repositorio.ufsc.br/xmlui/handle/123456789/77627.

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Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico.
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ROCHA, Thiago Lopes. "Biomarcadores comportamentais, histopatológicos e proteômicos da toxicidade aguda da formulação comercial do herbicida glifosato em poecilia reticulata." Universidade Federal de Goiás, 2012. http://repositorio.bc.ufg.br/tede/handle/tde/1266.

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The mechanism of acute toxicity of the commercial formulation glyphosate, Roundup Transorb® (RDT), was investigated in the guppy (Poecilia reticulata) gills using proteomic technologies associated with analyses of histopathological indexes (HI´s), followed by quantification of histopathological lesions of the gills. Additionally, the present study describes a protocol for the analysis of fish behavior using measurements of the Index of morphofunctional behavior (Imb) and Total (Itb). The results indicate that the acute toxicity of RDT may change P. reticulata behavior as a consequence of changes in the expression of proteins associated with cyto-histopathological lesions of the gills. RDT LC50,96h for guppy females was 7.54 ± 0.93 μL.L-1, indicating that the species is moderately sensitive to this herbicide. Acute exposure to RDT sublethal concentration of 3.8 μL.L-1 induced time-dependent histopathological lesions of the gills in different epithelial and muscle cell types. HI´s were related to increase in severity and frequency of histopathological lesions and suggest that RDT may cause regressive, circulatory, and progressive disorders in the guppy gills. Two-dimensional electrophoresis associated with mass spectrometry and biocomputing permitted to verify 48 spots of proteins/isoforms regulated by RDT, which are involved in different cell processes, such as energy metabolism, regulation and maintenance of cytoskeleton, metabolism of nucleic acids and proteins in response to stress. The study of behavior biomarkers (BM´s) indicates that Imb and Itb were viable in the analysis of P. reticulata behavioral changes induced by RDT. Furthermore, proteomic and histological changes in the gills of P. reticulata induced by RDT may be histopathological and proteomic BM´s to biomonitor water pollution caused by glyphosate-based herbicides.
O mecanismo de toxicidade aguda da formulação comercial de glifosato, Roundup Transorb® (RDT), foi investigado para as brânquias do guaru (Poecilia reticulata) por meio de tecnologias proteômicas associadas às análises dos índices histopatológicos (HI´s), seguido da quantificação das lesões histopatológicas branquiais. Além disso, o presente trabalho também descreve um protocolo para análise do comportamento de peixes utilizando mensurações dos Índices de Comportamento Morfofuncional (Icmf) e Total (Ict). Os resultados indicam que a toxicidade aguda do RDT pode alterar o comportamento de P. reticulata como reflexo das mudanças de expressão das proteínas associadas às lesões cito-histopatológicas branquiais. A CL50,96h do RDT para as fêmeas do guaru foi de 7,54 ± 0,93 μL.L-1, a qual indica que esta espécie é moderadamente sensível a esse herbicida. A exposição aguda à concentração subletal de 3,8 μL.L-1 de RDT induziu lesões histopatológicas branquiais de modo tempo dependente em diferentes tipos celulares epiteliais e muscular. Os HI´s foram relacionados com o aumento da severidade e da frequência das lesões histopatológicas e apontam que o RDT pode causar distúrbios regressivos, circulatórios e progressivos nas brânquias do guaru. A eletroforese bidimensional associada à espectrometria de massa e bioinformática permitiu verificar 48 spots de proteínas/isoformas reguladas pelo RDT, as quais estão envolvidas em distintos processos celulares, tais como metabolismo energético, regulação e manutenção do citoesqueleto, metabolismo de ácidos nucléicos e proteínas de resposta ao estresse. O estudo dos biomarcadores (BM´s) comportamentais indica que o Icmf e o Ict foram viáveis na análise das alterações comportamentais de P. reticulata induzidas pelo RDT. Ademais, as modificações proteômicas e histológicas nas brânquias de P. reticulata induzidas pelo RDT podem ser BM´s histopatológicos e proteômicos no biomonitoramento da poluição aquática por herbicidas baseados em glifosato.

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47

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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Medeiros, Louise de Souza [UNESP]. "Toxidade aguda e risco ambiental do inseticida teflubenzuron para Daphnia magna, Lemna minor e Poecilia reticulata." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/86698.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Os agrotóxicos aplicados nas áreas agrícolas podem ser carreados, por diversos mecanismos, até os corpos d’água da rede hidrográfica. Além disso, estes produtos são comumente utilizados na aqüicultura para o controle de parasitoses. O teflubenzuron (TFB) é um inseticida registrado em alguns países da Europa para o controle de parasitas de peixes. Os possíveis efeitos tóxicos e risco ambiental do TFB podem ser avaliados inicialmente em condições de laboratório por meio de testes de toxicidade aguda com organismos-teste eleitos internacionalmente. Os objetivos deste trabalho foram avaliar a toxicidade aguda e o risco de intoxicação ambiental do uso agrícola e em aqüicultura do TFB, com base nos valores de CE50 e CL50 estimados em testes com Daphnia magna, Lemna minor e Poecilia reticulata, utilizados como organismos bioindicadores. Os testes de ecotoxicidade aguda foram realizados de acordo com normas nacionais e internacionais para estas espécies. A CE50-48h estimada para D. magna foi 0,00026 mg.L- 1, o que caracteriza este inseticida como altamente tóxico para esta espécie. Para L. minor, a CE50-7d estimada foi 1.176,16 mg.L-1, e para P. reticulata CL50-96h, 2.707,87 mg.L- 1, que classificam o TFB como praticamente não-tóxico para estas duas espécies. Devido à alta toxicidade do TFB para daphnídeos, mesmo em pequenas contaminações, pode causar desequilíbrio na cadeia alimentar aquática. Para minimizar o risco ambiental, o TFB pode ser utilizado de forma controlada e diluído em quantidades restritas de água.
The pesticides used in agriculture areas can be transported to water bodies of the local hydrographic basin in several ways. Moreover, these chemicals are commonly used in aquaculture to fish parasite control. The teflubenzuron (TFB) is a registered insecticide in some European countries to this use. The possible effects of the TFB and environmental risk can be evaluated initially in laboratory conditions by tests of acute toxicity with internationally elected organisms. The objectives of this study were to evaluate the acute toxicity and the environmental risk due to agriculture and aquaculture use of TFB, based on the values of EC50 and LC50 estimated in tests with Daphnia magna, Lemna minor and Poecilia reticulata, internationally used as bioindicators organisms. The acute ecotoxicity tests were performed in accordance with national and international standards for these species. The EC50-48h estimated to D. magna was 0,00026 mg.L-1, which characterizes that as very highly toxic insecticide for this species. For L. minor, EC50-7d was estimated 1.176,16 mg.L-1, and P. reticulata LC50-96h, 2.707,87 mg.L-1, which classified the TFB as practically non-toxic to these species. Due to the high toxicity of the TFB to daphnids, even in little contamination, can cause a loss of equilibrium in the aquatic food chain. To minimize the environmental risk, the TFB can be used in a controlled way and diluted in limited quantities of water.

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Bleakley, Bronwyn H. "Indirect genetic effects of social environment influence the expression of antipredator behavior in guppies, Poecilia reticulata." [Bloomington, Ind.] : Indiana University, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3277974.

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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2007.
Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5787. Adviser: Edmund D. Brodie, III. Title from dissertation home page (viewed May 9, 2008).

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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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