Patterns of heterospecific matings are important to understand in order to learn about speciation. I proposed a classical signal detection model as a representation of heterospecific mating patterns in both sexes. From the model I proposed that males would be able to achieve successive heterospecific mating success, as those males were more similar to conspecifics. I also proposed that restrictive females that rejected heterospecific matings would also be more likely to reject conspecific matings. I used the sibling species Drosophila pseudoobscura and D. persimilis to examine heterospecific mating patterns in males and females. I found that males previously accepted as heterospecific mates were more likely to achieve heterospecific matings than males that had previously been rejected as heterospecific mates. This was most likely due to decreased courtship by rejected males. Males rejected heterospecifically but mated conspecifically also were less likely to achieve heterospecific matings than males that had initially been accepted as heterospecific mates. This indicated that the same males were able to achieve successive heterospecific matings, despite rejected males also having had initial mating success. This was again likely influenced by decreased courtship in rejected males. Furthermore, I found that females that rejected heterospecific males were also more likely to reject conspecific males than naive females. There was also a non-significant trend of females that previously accepted heterospecific males were more likely to again accept heterospecific males than females that had previously rejected heterospecific males. / Thesis / Master of Science (MSc)

<p>Genetic structuring is common in natural populations. It is important to identify and consider population structure when studying evolutionary processes. Recently, the discovery of genetic structuring in some lekking bird species has opened up new perspectives on our understanding of the evolution of lek mating systems.</p><p>This thesis uses molecular data to identify patterns of broad and fine scale genetic structuring in the lekking white-bearded manakin Manacus manacus. Additionally, data on male mating success, female visiting patterns and behavioural, morphological and territorial characteristics of individual males are used to identify variables that may influence the distribution of matings in this species.</p><p>Analysis of genetic divergence within the genus Manacus revealed genetic sub-structuring and limited gene flow between species/subspecies. There was no significant isolation by distance relationship. Factors such as physical barriers to gene flow may play a role in shaping the genetic structure of the bearded manakin genus.</p><p>White-bearded manakin leks on Trinidad were composed of groups of related males. More than one such kin group existed on each lek. That related males gather in groups suggests that genetic structuring is not simply a consequence of limited dispersal. Active choices must take place by both residential and newly arrived birds.</p><p>Female visits to, and matings with, males were non-random. Centrality of male display court was the only measured variable that consistently correlated with male mating success. More aggressive displays were made as the distance between courts decreased. There was no significant relationship between the number of aggressive displays made between males and relatedness levels. Males with high mating success spent more time in aggressive behaviours.</p><p>In conclusion, white-bearded manakin lek formation and display court acquisition is likely to be influenced by genetic relatedness levels and male-male interactions. Centrality of court seemed important in mating success and may be an indicator of male dominance. However, a variety of other factors may also influence mating success and may be variable over time.</p>

Genetic structuring is common in natural populations. It is important to identify and consider population structure when studying evolutionary processes. Recently, the discovery of genetic structuring in some lekking bird species has opened up new perspectives on our understanding of the evolution of lek mating systems. This thesis uses molecular data to identify patterns of broad and fine scale genetic structuring in the lekking white-bearded manakin Manacus manacus. Additionally, data on male mating success, female visiting patterns and behavioural, morphological and territorial characteristics of individual males are used to identify variables that may influence the distribution of matings in this species. Analysis of genetic divergence within the genus Manacus revealed genetic sub-structuring and limited gene flow between species/subspecies. There was no significant isolation by distance relationship. Factors such as physical barriers to gene flow may play a role in shaping the genetic structure of the bearded manakin genus. White-bearded manakin leks on Trinidad were composed of groups of related males. More than one such kin group existed on each lek. That related males gather in groups suggests that genetic structuring is not simply a consequence of limited dispersal. Active choices must take place by both residential and newly arrived birds. Female visits to, and matings with, males were non-random. Centrality of male display court was the only measured variable that consistently correlated with male mating success. More aggressive displays were made as the distance between courts decreased. There was no significant relationship between the number of aggressive displays made between males and relatedness levels. Males with high mating success spent more time in aggressive behaviours. In conclusion, white-bearded manakin lek formation and display court acquisition is likely to be influenced by genetic relatedness levels and male-male interactions. Centrality of court seemed important in mating success and may be an indicator of male dominance. However, a variety of other factors may also influence mating success and may be variable over time.

Competition over mating opportunities is a conspicuous characteristic of animal behaviour. In many butterfly species the males establish territories in places advantageous for encountering females. This thesis addresses questions about how territoriality has evolved and is maintained in butterflies. The studies have been conducted using the speckled wood butterfly, Pararge aegeria, as a model species. Males of P. aegeria are found in sunspots on the forest floor (paper I-V), on the lookout for females visiting the sunspots. However, males are only found in sunspots above a certain size (paper III). This behavior is maintained by a mating success advantage, where using large sunspots instead of small sunspots as perching areas generates a higher reproductive output (paper I). The mating success asymmetry is not explained by female choice or by a female preference for large sunspots per se (paper I, V), but rather the large sunspot facilitates visual performance of perching males and improves flight pursuit and interception of females (paper III). Winners of territorial contests gain sole ownership of large sunspot territories, while losers search for a new suitable sunspot territory (paper I, II &amp; IV) or use smaller, suboptimal sunspots as perching sites (paper II). Territorial contests between P. aegeria males are not settled due to an obvious morphological/physiological asymmetry (paper I). Rather, variation in resource value and motivational asymmetries are important for settling contests (paper IV). A majority of male-female interactions (paper V) and matings (paper I) are initiated by a perching male detecting and intercepting a flying female. Furthermore, females can affect their chances of being detected by a perching male by behaving more conspicuously (paper V). This thesis highlights the role of female behaviour, variation in resource value and motivation asymmetries to understand the evolution of territoriality in butterflies.

Within social insect colonies, sterile workers are responsible for brood care, while queens are the primary egg-layers. These reproductive caste differences are often accompanied by pronounced morphological distinctions. Queen and worker phenotypic differences are particularly remarkable considering caste is environmentally, rather than genetically, determined. Environmental caste determination can produce intralocus genetic conflict between castes, particularly when homologous traits are highly dimorphic. Therefore, when studying the evolution of social insect caste dimorphism, one must consider the genetic architecture underlying phenotypic expression as well as the selective pressures that have shaped caste morphology. This dissertation presents the results of four studies that investigated factors affecting caste morphology in the social wasp Vespula maculifrons. The first two studies focused on identifying queen morphological traits that were positively associated with queen fitness and would therefore be subject to selection. Queen length, specifically gaster length, was positively associated with overwintering survival and was consistently associated with mating success. Both of these findings suggest that queen gaster length is under selection during two life-history events, mating and overwintering, in which workers do not participate. These findings provide empirical support for the adaptive evolution of a caste dimorphic trait. The third and fourth studies used classical quantitative genetic and morphological analyses to examine the genetic architecture underlying caste dimorphism in V. maculifrons. I determined which traits were under caste-specific selection by analyzing trait allometries and the levels of genetic control, variation, and dimorphism of traits between castes. Little genetic variation for morphological trait size was detected for most worker and queen traits, suggesting a strong influence of environment on phenotypic variation. Additionally, analyses of trait allometries indicated that several queen traits (mass, thorax width and length) were under queen-specific selection. The relationship between thorax length, gaster length, and overall body size is further evidence of selection on length in queens. Overall, these studies provide evidence for the importance of queen-specific selection in the evolution of caste dimorphism. When placed in the broader context of caste evolution, they point to the importance of life-history in shaping the genetic architecture underlying caste dimorphism.

Males of European tree frog are clustered in the chorus in order to attract females. Males were re-captured, their body size and position in chorus was recorded. Goal of this thesis was investigated a correlation between the males' body size and mating behaviour and their position in the chorus.

In nest-building species, offspring survival and reproductive success of parental individuals are strongly influenced by nest location and quality. Thus, quantifying the influence of abiotic conditions on nest integrity is important to predict the effects that weather variability may have on offspring survival and parental reproductive success. Here we investigated how rainfall affects nest integrity and how nest integrity influences male attractiveness and nest tenure. Our study species was the harvestman Quindina limbata, in which males build cup-like mud nests on fallen logs and protect the eggs against predators and fungi infestation. Our dataset is based on 12 months of regular inspections of over 150 nests in a tropical rainforest from Costa Rica. We found that 43% of the nests were destroyed by rainfall. The drag force promoted by rainfall running on the log surface negatively affected nest integrity by decreasing the wall perimeter and the floor area. The intensity of fungi cover was not explained by nest position or by precipitation. No matter the body size of the owner males, nests with high integrity received more eggs than nests with low integrity. Curiously, nests with high values of fungi cover received more eggs. Finally, nest integrity and fungi cover did not affect nest tenure, but the probability of males abandoning their nests increased with time they did not receive eggs. Considering that intense rainfall occurs all year long in tropical forests, the best males can do to decrease the chances of nest destruction is to select protected places to build their nests. Protected sites may keep nest structure better preserved, improve offspring survival, attract more females, and ultimately increase male reproductive success / Em espécies que constroem ninhos, a sobrevivência da prole e o sucesso reprodutivo dos indivíduos parentais são fortemente influenciados pela localização e qualidade dos ninhos. Portanto, quantificar a influência das condições abióticas sobre a integridade dos ninhos é importante para prever os efeitos que a variabilidade climática pode ter na sobrevivência da prole e no sucesso reprodutivo dos pais. Neste estudo, investigamos como a chuva influencia a integridade dos ninhos e como a integridade dos ninhos influencia a atratividade masculina e o tempo de posse do ninho. Nossa espécie de estudo foi o opilião Quindina limbata, em que os machos constroem ninhos de barro em troncos caídos e protegem os ovos contra predadores e infestação por fungos. Nosso conjunto de dados é baseado em 12 meses de inspeções regulares de mais de 150 ninhos em uma floresta tropical na Costa Rica. Descobrimos que 43% dos ninhos foram destruídos pela chuva. A força de arrasto promovida pela chuva na superfície dos troncos caídos influenciou negativamente a integridade dos ninhos, diminuindo o perímetro da parede e a área do piso. A intensidade de cobertura de fungos não foi explicada pela posição do ninho ou pela precipitação. O tamanho corporal dos machos não influenciou o ganho de ovos, mas ninhos com alta integridade receberam mais ovos do que ninhos com baixa integridade. Curiosamente, ninhos com altos valores de cobertura de fungos receberam mais ovos. Por fim, a integridade dos ninhos e a cobertura de fungos não influenciaram o tempo de posse do ninho, mas a probabilidade de os machos abandonarem seus ninhos aumentou com o tempo em que não receberam ovos em seus ninhos. Considerando que temporais ocorrem durante todo o ano em florestas tropicais, os melhores machos devem selecionar locais protegidos para construção dos seus ninhos a fim de diminuir as chances de destruição promovida pela chuva. Locais protegidos podem manter a estrutura do ninho melhor preservada, melhorar a sobrevivência da prole, atrair mais fêmeas e, finalmente, aumentar o sucesso reprodutivo dos machos

In nest-building species, offspring survival and reproductive success of parental individuals are strongly influenced by nest location and quality. Thus, quantifying the influence of abiotic conditions on nest integrity is important to predict the effects that weather variability may have on offspring survival and parental reproductive success. Here we investigated how rainfall affects nest integrity and how nest integrity influences male attractiveness and nest tenure. Our study species was the harvestman Quindina limbata, in which males build cup-like mud nests on fallen logs and protect the eggs against predators and fungi infestation. Our dataset is based on 12 months of regular inspections of over 150 nests in a tropical rainforest from Costa Rica. We found that 43% of the nests were destroyed by rainfall. The drag force promoted by rainfall running on the log surface negatively affected nest integrity by decreasing the wall perimeter and the floor area. The intensity of fungi cover was not explained by nest position or by precipitation. No matter the body size of the owner males, nests with high integrity received more eggs than nests with low integrity. Curiously, nests with high values of fungi cover received more eggs. Finally, nest integrity and fungi cover did not affect nest tenure, but the probability of males abandoning their nests increased with time they did not receive eggs. Considering that intense rainfall occurs all year long in tropical forests, the best males can do to decrease the chances of nest destruction is to select protected places to build their nests. Protected sites may keep nest structure better preserved, improve offspring survival, attract more females, and ultimately increase male reproductive success / Em espécies que constroem ninhos, a sobrevivência da prole e o sucesso reprodutivo dos indivíduos parentais são fortemente influenciados pela localização e qualidade dos ninhos. Portanto, quantificar a influência das condições abióticas sobre a integridade dos ninhos é importante para prever os efeitos que a variabilidade climática pode ter na sobrevivência da prole e no sucesso reprodutivo dos pais. Neste estudo, investigamos como a chuva influencia a integridade dos ninhos e como a integridade dos ninhos influencia a atratividade masculina e o tempo de posse do ninho. Nossa espécie de estudo foi o opilião Quindina limbata, em que os machos constroem ninhos de barro em troncos caídos e protegem os ovos contra predadores e infestação por fungos. Nosso conjunto de dados é baseado em 12 meses de inspeções regulares de mais de 150 ninhos em uma floresta tropical na Costa Rica. Descobrimos que 43% dos ninhos foram destruídos pela chuva. A força de arrasto promovida pela chuva na superfície dos troncos caídos influenciou negativamente a integridade dos ninhos, diminuindo o perímetro da parede e a área do piso. A intensidade de cobertura de fungos não foi explicada pela posição do ninho ou pela precipitação. O tamanho corporal dos machos não influenciou o ganho de ovos, mas ninhos com alta integridade receberam mais ovos do que ninhos com baixa integridade. Curiosamente, ninhos com altos valores de cobertura de fungos receberam mais ovos. Por fim, a integridade dos ninhos e a cobertura de fungos não influenciaram o tempo de posse do ninho, mas a probabilidade de os machos abandonarem seus ninhos aumentou com o tempo em que não receberam ovos em seus ninhos. Considerando que temporais ocorrem durante todo o ano em florestas tropicais, os melhores machos devem selecionar locais protegidos para construção dos seus ninhos a fim de diminuir as chances de destruição promovida pela chuva. Locais protegidos podem manter a estrutura do ninho melhor preservada, melhorar a sobrevivência da prole, atrair mais fêmeas e, finalmente, aumentar o sucesso reprodutivo dos machos

L’abondance des insectes phytophages est déterminée par l’influence de facteurs biotiques et abiotiques qui affectent leurs traits d’histoire de vie. Chez les espèces phytophages à reproduction sur capital, la qualité de la plante hôte sur laquelle les individus effectuent leur développement larvaire est un facteur critique affectant le succès reproducteur des adultes. Curieusement, si l’effet de la plante hôte sur le potentiel reproductif des femelles a été largement décrit, il n’a été que peu étudié sur celui des mâles. Par ailleurs, chez les lépidoptères, lors de l’accouplement, la femelle reçoit du mâle un cadeau nuptial sous la forme d’un spermatophore contenant des spermatozoïdes ainsi que des sécrétions produites par les glandes accessoires. Ces sécrétions constituent des bénéfices directs pour la femelle qui pourra les remobiliser pour augmenter sa fécondité. Mon projet de thèse vise à déterminer l’influence de la plante hôte sur les performances reproductives des mâles et d’en évaluer les conséquences sur le potentiel reproductif des femelles et sur l’évolution des stratégies de choix de partenaire chez un papillon ravageur de la vigne, l’Eudémis (Lobesia botrana). Les expériences menées au cours de ces trois années de thèse révèlent que la nutrition larvaire sur différents cépages de vigne module fortement les réserves énergétiques des mâles, affectant leur potentiel reproductif à travers la taille et le contenu des spermatophores qu’ils transfèrent aux femelles pendant l’accouplement. De plus, l’investissement du mâle dans la production de spermatophores décline au cours d’accouplements successifs, les mâles n’étant capables de produire qu’un seul spermatophore riche en nutriments au cours de leur vie. Ces deux facteurs (nutrition larvaire et expérience sexuelle), qui affectent fortement la qualité reproductive des mâles, ont d’importantes conséquences sur le potentiel reproductif de leur partenaire. En effet, les femelles recevant des spermatophores riches en nutriments et en spermatozoïdes ont plus de descendants que celles recevant des spermatophores de moins bonne qualité. Enfin, les femelles semblent capables de discriminer parmi les mâles en se basant sur des critères reflétant leur qualité reproductive, s’accouplant préférentiellement avec ceux leur procurant le plus de bénéfices directs. Ainsi, les résultats de cette thèse confirment l’importance d’intégrer l’effet mâle quand on s’intéresse à l’évolution des populations de phytophages. De plus, identifier les facteurs écologiques modulant les interactions entre les partenaires sexuels chez les espèces menaçant les cultures est crucial pour pouvoir optimiser les programmes de gestion de ces ravageurs. / The abundance of phytophagous insects is determined by numerous interacting biotic and abiotic factors. In capital-breeding phytophagous insects, larval host plant quality is a key determinant of the adult phenotype and the performance of both males and females. Curiously, if the effect of host plant quality on female reproductive success is well-established, little effort has been conducted to determine this effect on male reproductive success. Moreover, in Lepidoptera, males transfer to females a spermatophore containing sperm and accessory gland products rich in nutrients that could be reinvested into female reproduction. The aim of this thesis was to evaluate how male larval nutrition on different host cultivars affects male reproductive traits which could, in turn, influence female reproductive output and mate choice strategies in an important grapevine pest, the European grapevine moth (Lobesia botrana). During these three years, we found that the host cultivar for the larvae strongly influences the energy reserves of male adult moths, affecting ultimately their reproductive potential through the size and content of spermatophores they transfer to females at mating. Moreover, male investment in the spermatophore declines over consecutives matings, suggesting that spermatophores are energetically expensive to produce in this monandrous capital breeding species. Thus ‘male quality’ depends on both the male larval origin and mating history, and females receiving protein-rich spermatophores at mating have an overall greater reproductive output than females mated with poor quality males producing less nutritionally rich spermatophores. Finally, females are able to discriminate among males and mate more with males having high sperm quality (virgin males or males from certain cultivars or geographical origins) to obtain substantial direct benefits.The results of this thesis confirm the importance of considering the “male effect” when trying to understand the evolution of phytophagous populations. Moreover, identifying the ecological conditions that influence the mating success of male and female in crop-pest species may lead to a better management of these crop pests.