Les interactions comportementales entre hétérospécifiques, lors du contact entre deux populations auparavant isolées, sont source de nouvelles pressions de sélection sur les traits affectant ces interactions. Les traits impliqués notamment dans les interactions reproductives et compétitives évoluent en fonction de ces pressions et ces adaptations peuvent influencer le processus de spéciation. La communication entre individus joue un rôle particulièrement important dans la régulation des interactions comportementales intra et inter-spécifiques. L'évolution de la reconnaissance spécifique peut notamment permettre d'adapter les réponses comportementales lors des rencontres en fonction de l'identité spécifique des individus. Les études empiriques présentées ici ont eu pour objectif de tester, chez un organisme modèle (deux sous espèces de la souris domestique), le rôle de la sélection sexuelle contre les hybrides et de la compétition mâle-mâle par interférence dans la mise en place de l'isolement reproducteur. Nos résultats montrent que la sélection sexuelle peut avoir un double effet dans la zone hybride entre Mus musculus musculus et M. m. domesticus : réduire la fitness des hybrides, et limiter le flux de gènes à travers la zone. La compétition par interférence ne semble par contre pas avoir un rôle important dans l'évolution de la reconnaissance spécifique relativement aux pressions émergeant des interactions reproductives. Nos résultats mettent également en évidence des asymétries dans l'intensité des préférences homogames en zone de contact, qui pourraient être représentatives de pressions de sélection inégales entre sexes et entre sous-espèces. Cette dissertation se clôt sur une discussion sur les interactions entre différents processus évolutifs suite à un contact, et sur la notion de reconnaissance spécifique. / Behavioural interactions between heterospecifics, when two previously isolated populations come into contact, generate new selective pressure on traits involved in those interactions. Particularly, the traits involved in reproductive and competitive interactions evolve due to this selection, and these adaptations can affect the speciation process. Communication plays an important role in the regulation of behavioral interactions, both between and within species. Evolution of species recognition allows behavioral adjustment to the species of the encountered individuals. The empirical studies presented here aimed to test, on a model organism (two house mice subspecies), the role of sexual selection against hybrids, and of male-male interference competition, in the evolution of reproductive isolation. Our results show that sexual selection can act in th hybrid zone between Mus musculus musculus and M. m. domesticus, by reducing hybrid fitness, and by impeding gene flow through the zone. Interference competition however do not seem to be an important driver of the divergence of species-specific signals in the contact zone, and reinforcing selection is probably at the origin of this character displacement. Our results also enlighten asymmetries in homogamous preferences intensity, which could be due to differences in selective pressures depending on sex an subspecies. This dissertation ends on a discussion on interactions between process at play at secondary contact, and on the notion of species recognition.

A Research Report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science. Johannesburg, 25 May 2015. / The African elephant, Loxodonta africana displays sexual segregation, a phenomenon which describes males and females of the same species living separately, except during the mating season. Despite it occurring in many sexually dimorphic species, the factors that govern sexual segregation are still poorly understood. The aim of my study was to investigate whether or not African elephants in the 1825 km2 Associated Private Nature Reserves (APNR), Limpopo Province were sexually segregated as a result of habitat segregation. I tested the Forage Selection Hypothesis (FSH) which, based on the Jarman-Bell principle, predicts that smaller females are more selective foragers as a result of their high energy demands and poor digestive capabilities in comparison to the larger males. Using the GPS location data of 18 collared adult elephants (12 male and 6 female) from November 2008 to November 2010, I plotted both the total (95% isopleth) and core (50% isopleth) home ranges of individual elephants. I used these home ranges to i) confirm sexual segregation in the APNR, ii) determine whether or not there was a difference in vegetation composition of the home ranges between males and females, and iii) to establish how frequently male and female elephants were associated with each of the vegetation types located within their home ranges. All analyses were done at both the total and core home range level. Home range overlaps were rare between male and female home ranges, particularly at the core home range level, confirming sexual segregation of elephants in the APNR. The vegetation composition data of the home ranges as well as the frequency of association by elephants with each of the available vegetation types (using GPS locations) revealed no significant difference between male and female elephants. Therefore, habitat segregation did not explain sexual segregation by elephants in the APNR. I propose that future studies should consider: i) temporal distribution of elephants to assess how much time each sex spends in each of the available vegetation types; ii) other resources, particularly the availability of water, in addition to the availability of forage, since water limits elephant movements; and iii) social segregation in conjunction with habitat segregation, since elephants display sex-specific differences in social organisation. A comprehensive understanding of the factors that govern sexual segregation of elephants might contribute to conservation management of elephants in the APNR and other small reserves.

Social monogamy, closely associated with bi-parental care, is the most frequent pairing system found in birds. Because females invest more into the reproduction, they are usually considered to be the sex that chooses the partner. To satisfy female preferences in the mate choice males in various species developed a number of traits that signalize their quality. What qualities are signaled by these traits and what mechanisms are responsible for the emergence, development and maintenance of these traits is the subject of a number of evolutionary- ecological studies. By pairing with an appropriate male female can obtain direct or indirect benefits to its own fitness. The good parent theory suggests that male secondary sexual traits signalize male ability to provide parental care (a direct benefit). An indirect benefit is presented by the quality of the genetic material that the female obtains from male for her offspring. According to the good genes hypothesis females use secondary male ornamentation to assess genetic quality of males. One of the most studied secondary sexual ornaments that can advertise male quality and may be used in mate choice by females is the plumage colouration. In many avian species there is sexual dimorphism in the plumage colouration and there is also growing evidence that...

Meliponiculture (or stingless beekeeping) is a powerful tool for sustainable economic development in the tropics. However, meliponiculture has many challenges as it lacks standardization in management and breeding practices. The aim of this thesis was to investigate stingless bee reproductive biology combined to management and breeding as background to meliponiculture improvement. In chapter 1, we performed a meta-analysis of heritability across the Hymenoptera in order to review current knowledge and discuss the challenges for bee breeding and conservation. In chapter 2, we assessed how sexual selection acts on male traits in the stingless bee Scaptotrigona aff. depilis and identified which traits may affect male fitness. In chapter 3, we estimated heritability and genetic correlations for the traits studied in the previous chapter, to understand how evolution shapes male traits and to identify important traits for breeding programs. Finally, in chapter 4 we investigated how the environment and long-term management influence colony productivity in Melipona subnitida (jandaíra), a commercially managed species in Northeastern Brazil. Our results revealed that morphological traits exhibit higher heritability estimates than fitness related traits, and in general, colony productivity traits showed potential for breeding. However, few studies are available for stingless bees yet. Male aggregations in S. aff depilis selected competitive males with higher quality sperm, indicating the importance of this mechanism in stingless bee mating biology. The studied male traits exhibited high heritability estimates, with exception of sperm length. Since aggregations selected males with shorter sperm, these results suggest selection for long-term sperm storage by queens and higher fertilization potential. The assessment of M. subnitida records revealed that honey production was affected by climate and management, and strategies to improve beekeeping practices were discussed. We believe this thesis provides important guidelines to establish successful stingless bee breeding programs / A meliponicultura, criação racional de abelhas sem ferrão, é uma poderosa ferramenta para o desenvolvimento econômico sustentável em regiões tropicais. No entanto, a prática da meliponicultura enfrenta diversos desafios, como a falta de padronização das técnicas de manejo e melhoramento genético. O objetivo desta tese foi investigar a biologia reprodutiva de abelhas sem ferrão aliada ao manejo e ao melhoramento genético, a fim de fornecer subsídios para o aprimoramento da meliponicultura. No capítulo 1, realizamos uma meta-análise sobre herdabilidade em Hymenoptera, a fim de compreender o conhecimento atual e os desafios associados ao melhoramento genético de abelhas e sua conservação. No capítulo 2, avaliamos como a seleção sexual atua em caracteres dos machos da espécie Scaptotrigona aff. depilis e identificamos quais caracteres podem influenciar o sucesso reprodutivo. No capítulo 3, estimamos a herdabilidade e correlações genéticas para os caracteres avaliados no capítulo anterior, a fim de entender como a evolução atua moldando os caracteres dos machos e quais desses caracteres podem ser utilizados em programas de melhoramento genético. Finalmente, no capítulo 4, investigamos o efeito do ambiente e do manejo na produtividade de colônias em Melipona subnitida (jandaíra), uma espécie manejada comercialmente no Nordeste brasileiro. Nossos resultados revelaram que caracteres morfológicos exibem estimativas de herdabilidade mais altas do que caracteres ligados ao sucesso reprodutivo. No entanto, poucos estudos com abelhas sem ferrão foram realizados até o momento. Agregações de machos em S. aff. depilis selecionaram machos mais competitivos que apresentaram maior qualidade espermática, indicando a importância desse mecanismo na biologia reprodutiva de abelhas sem ferrão. Os caracteres estudados apresentaram alta herdabilidade, com exceção do comprimento do espermatozoide. Como agregações selecionam machos com espermatozoides mais curtos, esses resultados sugerem seleção direcionada para um maior tempo de armazenamento do esperma pelas rainhas e maior potencial de fertilização. A avaliação dos registros de M. subnitida revelou que a produção de mel foi afetada pelo clima e pelo manejo, e estratégias a fim de melhorar as práticas da meliponicultura foram discutidas. Acreditamos que essa tese fornece importantes resultados para o estabelecimento de programas de melhoramento genético em abelhas sem ferrão

Genitálias de machos tendem a apresentar maior elaboração e taxas de evolução mais altas que as de fêmeas, fenômeno cujos mecanismos associados ainda são pouco compreendidos. Nesta tese buscamos explorar tais mecanismos através da compreensão sobre os papéis funcionais e do desenvolvimento por trás da diversificação genital em Pentatomidae. No primeiro capítulo, investigamos o funcionamento das peças genitais externas em machos e fêmeas de espécies de diferentes linhagens, identificando grupos de estruturas que funcionam de forma mais integradas entre si. Mostramos que existem marcas funcionais únicas a algumas linhagens, mas por outro lado algumas características são conservadas e se repetem em todas as espécies. No segundo capítulo, inferimos uma filogenia para Pentatomidae usando dados moleculares e morfológicos, com enfoque na subfamília mais diversa e confusa taxonomicamente, Pentatominae. Identificamos diversas linhagens propostas na literatura com grande suporte, corroboramos a monofilia de Pentatomidae e a polifilia de Pentatominae. No terceiro capítulo, testamos a hipótese de que diferentes componentes genitais em fêmeas possuem maior restrição evolutiva por serem mais integradas durante o desenvolvimento, em comparação aos machos. Corroboramos esta hipótese, e sugerimos que as genitálias dos machos são evolutivamente moldadas pela forma como funcionam na cópula, enquanto a diversificação nas fêmeas é restringida por sua origem ontogenética. / Male genitalia tend to show greater elaboration and evolve faster in relation to females, a phenomenon whose underlying mechanisms are still poorly understood. In this thesis, we explore these mechanisms seeking to understand the functional and developmental roles in the diversification of genitalia in Pentatomidae. In the first chapter, we investigated the function of the external genital parts in males and females from different lineages, with the goal of identifying structures that work in a more integrated fashion. We showed that each species have unique functional signals, but some characteristics are more conserved and invariable. In the second chapter, we inferred a phylogeny to the Pentatomidae using morphological and molecular data, focusing on the most diverse and taxonomically confusing subfamily, Pentatominae. We recognized several lineages proposed on the literature with strong support, corroborate the monophyly of Pentatomidae and the paraphyly of Pentatominae. In the third chapter, we test the hypothesis that different genital components in females are more evolutionarily constrained for being more integrated during the development, comparing to males. We corroborated this hypothesis and suggest that male genitalia are evolutionarily shaped by their functional roles in copula, while the diversification in female genitalia is more constrained due to its ontogenetic origin.

De acordo com o modelo de seleção intersexual mediado por parasitas, variações nas condições de ornamentos ou taxa de displays sexuais refletem diferentes graus de resistência ao parasitismo. Em coros naturais de anfíbios, vocalizações mais altas, longas e complexas e/ou emitidas a maiores taxas são, provavelmente, mais facilmente detectadas e atraem mais fêmeas. Entretanto, o esforço vocal está positivamente relacionado aos níveis plasmáticos de esteróides potencialmente imunossupressores, tais como testosterona e corticosterona. O objetivo deste trabalho foi avaliar as relações entre taxa de vocalização, imunocompetência e níveis plasmáticos de corticosterona em Hypsiboas albopunctatus, um anuro de médio porte que ocorre na América do Sul. Tais relações foram estudadas a partir de observação focal do comportamento vocal em coro natural, seguido de coleta de sangue para dosagem de corticosterona e avaliação de alguns parâmetros imunitários. O presente estudo demonstrou uma relação positiva entre a taxa de vocalização com níveis plasmáticos de corticosterona e negativa entre estes dois parâmetros com a imunocompetência mediada por células. Estes resultados apontam para a corticosterona como possível hormônio mediador do compromisso entre esforço vocal e imunidade mediada por células em anuros. / According to the model of intersexual selection mediated by parasites, changes in conditions of sexual ornaments or display rates reflect different degrees of resistance to parasitism. In natural choruses of amphibians, calls that are higher, longer, more complex and / or issued at higher rates are probably more easily detected and attract more females. However, the vocal effort is positively related to plasma levels of potentially immunosuppressive steroids, such as testosterone and corticosterone. The aim of this study was to evaluate the relationship between calling rates, immunocompetence and plasma levels of corticosterone in Hypsiboas albopunctatus, a midsize anuran occurring in South America. Such relationships were studied from focal observations of calling behavior, followed by blood collection for measurements of corticosterone plasma levels and evaluation of some immune parameters. The present study showed a positive relationship between the calling rate with plasma levels of corticosterone, and a negative correlation between these two parameters with cell-mediated immunocompetence. These results highlight the importance of the hormone corticosterone as a possible mediator of trade-off between vocal effort and cell-mediated immunity in anurans.

The barn swallow (Hirundo rustica) is represented by six subspecies and has two well-studied ornamental traits, tail length and ventral plumage colour, which vary geographically among subspecies. Sexual selection on these traits has been suggested to drive speciation. The European subspecies rustica has pale ventral feathers and long tail streamers, and females prefer males with longer tail streamers. The North American erythrogaster has shorter tails and red ventral plumage and their females use redness of ventral plumage as a mate choice cue. In the Middle East, the subspecies transitiva bears long tail streamers and red ventral feathers, both of which have been suggested to show male attractiveness. The Asian subspecies gutturalis has a pale belly with short but dimorphic tails. Studies in Japanese populations have suggested that the white spot on the tail feathers and throat patch are sexually selected in males, but this explanation leaves the dimorphism of tail streamers unexplained. To further investigate the sexually selected traits of gutturalis, especially the role tail streamers might play, I studied a population of the barn swallow gutturalis in China between 2013 and 2015, and conducted a partial cross-fostering experiment in 2015. My data indicate that male tail streamers are sexually selected in the gutturalis population in China. Longer-tailed males (with deeper fork tails) were cuckolded less frequently and had a higher reproductive success, they also had mates that invested more in parental care and had a higher total peak body mass of offspring. Both male and female body condition (body mass and tarsus length) influenced offspring growth. Males with larger body mass initiated breeding earlier and their offspring had a larger body mass on day seven after hatching and grew faster as determined by a cross-fostering experiment. Larger females reared offspring that grew faster and reached a higher peak body mass both in original nests and nests with cross-fostered nestlings. Based on feeding rate observations and the cross-fostering experiment, it seems that females obtain indirect benefits rather than direct benefits from mating with more attractive males.

Sexual selection is ubiquitous in all sexually reproducing species and a powerful evolutionary force. The effect of sexual selection on population fitness has caused wide debate and has been proposed to both enhance adaptation rates, but also possibly increase extinction risk. Using experimental evolution, the strength of sexual selection was altered by biasing adult sex ratios in replicated populations of the Indian meal moth, Plodia interpunctella. Under increasing temperatures strong sexual selection and polyandry was associated with increased population fitness. Suggesting sexual selection could provide a buffer against climate change by increasing adaptation rates. However, no effect on male mating success was observed. In contrast, under stable temperatures male mating success was increased by strong sexual selection, however, this did not translate to increased population fitness. These results indicate that female choice is a potentially strong selective pressure in P. interpunctella. Moreover, under stabilising and directional selection the costs and benefits of sexual selection change. In a field study, dung beetle species richness and abundance were compared across a gradient of habitat disturbance, ranging from old-growth rainforest to oil palm plantation. Species persistence within altered habitats was positively associated with expressing horns and relative horn lengths, suggesting male-male competition increases a species ability to persist within modified landscapes. There was not a strong effect of relative testes mass or sexual size dimorphism on the abundance of species. Additionally, by examining the expression of sexually selected traits within species, horn length and testes mass appear to be condition dependent, but only the expression of horns was effected by habitat change. Overall, from both laboratory and field studies it was found that sexual selection can increase adaptation rates and the persistence of species within altered and changing environments. Moreover, both sets of studies suggest pre-copulatory sexual selection to be an important aspect of sexual selection in driving this adaptation.

Orientadora: Eliana Gonçalves de Freitas / Banca: Silvia Maria Guimarães de Souza / Banca: Mateus José Rodrigues Paranhos da Costa / Banca: Silvia Mitiko Nishida / Banca: Rodrigo Egydio Barreto / Resumo: O comportamento reprodutivo dos teleósteos envolve a seleção de parceiros para acasalamento por meio de escolha da fêmea e da disputa entre machos. A disputa pode levar à formação de hierarquia de dominância, na qual os machos dominantes têm vantagem no acasalamento por impedir que outros machos se aproximem da fêmea. Por outro lado, é possível que a fêmea prefira machos com maior habilidade competitiva, antes da formação da hierarquia. Assim, para compreender os fatores que afetam a preferência da fêmea e se a presença da fêmea durante as competições fornece vantagem na luta dos machos, realizamos dois estudos com a tilápia-do-Nilo (Oreochromis niloticus). O primeiro estudo testou a preferência das fêmeas em relação à características indicadoras da habilidade competitiva dos machos, sem a interferência da competição entre eles. Para isso, uma fêmea foi submetida ao contato visual com dois machos isolados e a preferência por um deles foi testada. Posteriormente os mesmos machos interagiram e estabeleceram a dominância. O macho preferido não se tornou dominante. Assim, não houve associação entre a preferência da fêmea e características indicadoras da habilidade competitiva dos machos. No segundo estudo testamos o efeito do contato visual de um macho com uma fêmea sobre a disputa hierárquica entre machos, uma vez que as interações macho-fêmea podem modular a reprodução e agressão dos peixes. Para isso, um macho em contato visual prévio com uma fêmea interagiu com um macho previamente isolado até o estabelecimento hierárquico. Porém, o macho em contato visual com a fêmea não se tornou dominante nem emitiu maior freqüência de ataques ao oponente. A presença da fêmea causou aumento do Índice Gonadossomático do...(Resumo completo clicar acesso eletrônico abaixo) / Abstract: Reproductive behavior of many fish species is performed by sexual selection and mate choice based on male-male contests. In such situation, selection is related to individual male competitive ability. Competition causes a social hierarchy, and dominant fish takes advantages for mating by avoid subordinate approach of females. Thus, it is possible that female prefer highest competitive ability males. To understand factors affecting female preference and, whether female presence can affect reproductive male ability, we performed two studies with Nile tilapia (Oreochromis niloticus) to understand the factors involved in dominance and female choice. In the first study we tested the female preference for highest competitive ability male. For this purpose, a female was kept in a visual contact with two males and the preference was tested by recording time female spent near to them. After that, both males were put together to fight, and we analyzed the chosen male was the winner. There was no association between female choice and male competitive ability. In the second study, we tested the effect of male visual contact with female and we supposed this could guarantee victories in a contest. Thus, a male was kept seeing a female during 6 days, and after that it was paired with a 6-days isolated male until hierarchical settlement. Female presence causes gonadosomatic index rise, but did not enhance chances for male victory in the social contest. This means that males that have more developed gonads do not take advantage in social interactions. Finally, we concluded that: i) females showed preference for one male; ii) female preference is not associated to male competitive ability; iii) visual stimulated males by female (with better gonadal condition) have not advantage in the hierarchy settlement. / Doutor

Parental care is important to offspring survival in many species. Because care benefits young and is often costly to parents, it can generate fitness trade-offs that influence the evolution of family life. In particular, interactions within families are predicted to generate variation in care, which in turn causes selection on traits used to give, receive, and influence care. My dissertation examines whether such socially dynamic processes have influenced the evolution of parental and embryo behavior in glassfrogs (Centrolenidae). These Neotropical frogs have terrestrial eggs, aquatic larvae, and multiple origins of male-only care. Embryos can plastically alter hatching age, which might allow them to adaptively respond to variation in egg care. I test for parent–embryo coevolution by combining field observations (40 species), experiments (8 species), and phylogenetic comparative analyses. First, I test historical and functional hypotheses of parental care evolution. I found that uniparental egg-care is ubiquitous in centrolenids, can be provided by either sex, and benefits young. Elaborate male-only care evolved repeatedly from simpler female-only care, a pattern consistent with constraints on female-care levels. Second, I examine the diversification of male-only care, testing whether maternal changes to egg-clutch traits influence embryo dependency and if such changes are associated with male-only care. Evidence indicates that reduced female expenditure on egg-jelly evolved with, and increases the importance of, elaborate male care. Next, I evaluate whether embryos respond to behavioral and evolutionary changes in parenting. Embryos behaviorally delay hatching when parents continue caring, and evidence indicates that evolutionary increases in hatching plasticity evolved with increases in care duration. I tested if male mating success causes variation in male care, and thereby influences embryo behavior. I found that increased mating success extends male care, making nests safer, and embryos delay hatching accordingly. Finally, I examine selective tradeoffs influencing hatching plasticity by measuring hatchling phenotypes and fitness correlates. Across species, delayed hatching provides performance benefits during the larval stage. Overall, my work reveals coevolutionary interactions among mothers, fathers, and embryos. It supports that embryos respond to parentally mediated changes in egg environments and elucidates how family life alters selection on parental and embryo traits.