This theses focuses on olfactory and visual components of mate choice in grey partridge. The aim is to evaluate the importance of melanin-based ornametnation and olfaction in mate choice and to explain the role of sexual selection in the evolution of secondary ornamentation in this socially monogamous galliform bird. To do that several experiments were conducted to (1) assess the ability of individuals to recognize conspecific odour and (2) to estimate the significance of melanin based feather ornamentation in male-male and male-female interactions. In some experiments I manipulated the expression (size) of feather maleanin- based ornamentation while in others I used birds forced to pair randomly to find out how the size of ornament and similarity in ornament expression between males and females (assortative pairing) affects reproductive success and investments (egg hatchability and number of eggs laid).

Sexual selection arises via competition for access to mates, and is thus intimately tied to the social environment. For example, individual mating success may depend strongly on how many rivals or mating partners are available. Studies of mate choice and sexual selection may vary the number of mates a subject is presented with during mating experiments, yet it is not clear how this influences the strength and shape of sexual selection acting on traits in either sex. In this thesis I investigate the effect of social environment on sexual selection acting in two closely-related species of lygaeid seed bug: Lygaeus equestris and Lygaeus simulans. Males in both species possess an extremely elongate intromittent organ, which is over two-thirds average male body length. I show that the strength of pre-copulatory selection acting on male processus length in Lygaeus equestris and genital clasper shape in Lygaeus simulans is significantly influenced by the social context. However, selection on male and female body size in Lygaeus equestris is not. Additionally, I use a meta-analysis of 38 published studies to show that mating preferences are significantly stronger when more than one mate option is available, compared to when only a single option is available. I also investigate the functional morphology of male genital traits in Lygaeus simulans, and use formal selection analysis to quantify the strength of selection acting on these traits before, during and after mating. Finally, I use experimental manipulations in Lygaeus simulans to confirm that male processus length directly influences sperm transfer, and that intact genital claspers are required for successful intromission. Overall, my results illustrate that sexual selection in the wild may vary both spatially and temporally depending on the social environment. It is thus especially important that experiments are performed under ecologically relevant conditions.

O cuidado paternal exclusivo à prole é a forma mais rara de investimento parental pós-zigótico na natureza, tendo evoluído independentemente em não mais do que 14 linhagens de artrópodes. Embora muitas dessas espécies sejam facilmente observadas e manipuladas, apenas recentemente os pesquisadores começaram a prestar atenção e a testar hipóteses sobre investimento parental e evolução de papéis sexuais nesses interessantes sistemas biológicos. O principal objetivo desta tese foi investigar características individuais e populacionais que poderiam afetar o sucesso reprodutivo de machos de opiliões (Arachnida: Opiliones) com cuidado paternal. No primeiro capítulo, fazemos uma revisão teórica detalhada, desde trabalhos clássicos de papéis sexuais até os mais recentes avanços, abordando também de maneira sistemática o conhecimento atual acerca de custos e benefícios do cuidado paternal em artrópodes, assim como o papel da seleção sexual sobre a evolução do comportamento parental e dos papéis sexuais. Em seguida, nos capítulos 2 e 3, acessamos os custos energéticos e em termos de sobrevivência do cuidado paternal nos opiliões Iporangaia pustulosa e Zygopachylus albomarginis. Comparando essas duas espécies, que apresentam diferentes níveis de investimento paternal, testamos previsões direcionadas de que os machos que investem mais na prole deveriam pagar maiores custos do cuidado. No quarto capítulo, por meio de informações da história natural e parâmetros populacionais estimados para I. pustulosa, fazemos previsões sobre qual dos sexos deveria ser criterioso ao escolher parceiros e as testamos utilizando observações comportamentais de interações entre machos e fêmeas. Por fim, no capítulo 5, avaliamos a importância relativa do sítio de oviposição, assim como do tamanho e do estado parental dos machos sobre a sua atratividade. Ao final, integramos os resultados obtidos em um corpo teórico sobre a inter-relação entre aparentes demandas conflitantes entre esforço parental e esforço reprodutivo, cuidado paternal e papéis sexuais, abrangendo não apenas as espécies estudadas, mas com um escopo bem mais amplo / Exclusive paternal care is the rarest form of post-zygotic parental investment in nature, which has independently evolved in no more than 14 arthropod lineages. Although many of those species are easily observed and manipulated, only recently researchers have started to pay attention and test hypotheses on parental investment and evolution of sex roles in such interesting biological systems. The main goal of this thesis was investigating individual and population characteristics that affect the reproductive success of males of harvestmen (Arachnida: Opilioes) with paternal care. In the first chapter, we revise the theory in details, since seminal works on sex roles until the most recent advances in the area, sistematically approaching the current knowledge abot costs and benefits of paternal care in arthropods, as well as the role of sexual selection on the evolution of parental behavior and sex roles. Then, in chapters 2 and 3, we access energetic and survival costs of paternal care in the harvestmen Iporangaia pustulosa and Zygopachylus albomarginis. Comparing these two species, that show different levels of parental investment, we test directional predictions that males which invest more should also pay more intense costs rekated to care. In the fourth chapter, based on natural history information and population parameters for I. pustulosa, we predict which sex should be choosier when selecting sexual partners, and test such predictions using behavioral data on male-female interactions. Finally, in chapter 5, we evaluate the relative importance of oviposition site, males\' body size and males\' parental state on their attractiveness. At the end, we integrate all the results obtained during the five chapters into a theoretical framework about the inter-dependence among trade-offs between parental and mating efforts, paternal care and sex roles, not only regarding the pair od species studied, but in a broad way.

Male mate choice occurs in species in which males face high mating costs, leading to few opportunities to copulate. Additionally, if male-male competition is strong, male mate choice should be influenced by male fighting ability. Good competitors should choose high quality females because they may be able to fight off contenders, while poor competitors should choose lower quality females. In Nephila clavipes spiders, males have limited sperm supply and fight for access to females. Here, using field experiments and observational data, we tested whether female quality and male size (a proxy of fighting ability) affect the pairing likelihood of males. In our experiments, we found that males did not express mate choice initially, but, after a few hours, chose their mates based on female size and female recent pairing status. Importantly, male mate choice direction and intensity varied with male size, as large males guarded larger females that were not recently paired and small males guarded smaller females that were recently paired. The observational data provided little evidence of assortative pairing regarding body size. With our field experiments, we show that crucial information can be collected by assessing mate choice in multiple moments. Taken together, our findings reveal the importance of considering male traits and the social context in understanding variation in male mate choice, which is often neglected in empirical studies / A escolha de parceiras por machos ocorre em espécies em que machos sofrem altos custos associados ao acasalamento, o que gera poucas oportunidades para copular. Adicionalmente, se a competição entre machos é intensa, a escolha de parceiras por machos deveria ser afetada pela habilidade de luta dos machos. Bons competidores deveriam escolher fêmeas de alta qualidade porque eles seriam capazes de afastar rivais, enquanto maus competidores deveriam escolher fêmeas de má qualidade. Em aranhas da espécie Nephila clavipes, machos possuem um estoque limitado de esperma e lutam pelo acesso a fêmeas. Usando experimentos de campo e dados observacionais, testamos se a qualidade das fêmeas e o tamanho dos machos (variável operacional de habilidade de luta) afetam a probabilidade de pareamento dos machos. Nos nossos experimentos, vimos que machos não expressam escolha de parceiras inicialmente, mas, depois de algumas horas, escolhem parceiras baseado no tamanho e no estado recente de pareamento delas. A direção e intensidade da escolha de parceiras por machos variou com o tamanho dos machos, pois machos grandes guardaram fêmeas maiores que não estavam pareadas recentemente, enquanto machos pequenos guardaram fêmeas menores que estavam pareadas recentemente. Nossos dados observacionais forneceram pouca evidência para pareamento assortativo referente a tamanho corporal. Com nossos experimentos de campo, mostramos que informação crucial pode ser coletada avaliando a escolha de parceiras em diferentes momentos. Em conjunto, nossos resultados revelam a importância de considerar características dos machos e contexto social no entendimento da variação na escolha de parceiras por machos, que é comumente negligenciada em estudos empíricos

Die Heuschreckenart Chorthippus biguttulus (Orthoptera: Acrididae) ist ein Modellorganismus für akustische Kommunikation. Die Männchen stridulieren durch Reiben des Hinterbeins gegen eine Flügelvene. Diese Dieser Gesang bietet Weibchen Informationen über Artzugehörigkeit, Geschlecht und u.U. die Qualität. Rezeptive Weibchen antworten auf arteigene und attraktive Gesänge. Ich untersuchte, welche Informationen der Männchengesang enthält, wie diese sich in Gesangsparametern manifestieren und welche Informationen rezipiert werden. Ich untersuchte Abhängigkeiten zwischen Gesang und Temperatur, Alter, Morphologie und Immunkompetenz. Ebenfalls testete ich auf eine Infektion mit Wolbachia sp.. Mit Playback-Versuchen wurde die Präferenz der Weibchen getestet. Der Sexualdimorphismus, Populationsunterschiede und Unterschiede zwischen Freiland- und F1-Populationen wurden untersucht. Es konnte gezeigt werden, dass die Männchengesänge in geringem Maße altersabhängig waren während sie Temperatur den Gesang stark beeinflusst. Länger andauernde Nymphenphasen induzierten veränderte Gesangsmerkmale. Größere und schwerere Beine korrelierten mit dem Onsetsowie der Versdauer und der Pausendauer. Die Phasenverschiebung der Hinterbeine hing stark mit der Störpausentiefe und der Thoraxbreite zusammen. Die Werte der Immunkompetenz korrelierten positiv mit dem Onset des Gesangs des jeweiligen Männchens sowie der Femurlänge. Die Weibchen bevorzugten Männchengesänge, die tiefe Offsets, lange Periode, bzw. Silben, geringe Störpausen und besonders lange Versdauern aufwiesen. Die Tiere zeigten einen hohen Grad an Sexualdimorphismus in Morphologie und Gesang. Ebenfalls waren starke Unterschiede in fast allen untersuchten Morphologiemerkmalen und den meisten Gesangsparametern verschiedener Populationen von Männchen festzustellen, wobei die Weibchenpräferenzen ähnlich waren und der artspezifische Parameter, das Silben-Pausen-Verhältnis, sich nicht unterschied. / The grasshopper Chorthippus biguttulus (Orthoptera: Acrididae) is a model organism for acoustic communication. The males stridulate by rubbing the hind legs against their forewings. The "song" is species-specific and contains information about the gender and perhaps about the quality. Receptive females answer by singing, if the male song is attractive. I worked on the question, which information about the male is in the song, which song parameters contain the information and which of these information is received by the females. I tested correlations between the song parameters and temperature, age, morphology and immunocompetence and I tested for an infection with Wolbachia sp.. The females’ preferences on male songs were tested with playback-experiments. I investigated the sexual size dimorphism and behavioral differences and the differences in these parameters of animals of different sites in Germany and of laboratory and field animals. The male songs were on a small scale age-dependent. Temporal parameters) depended very much from the temperature and decrease with higher temperatures. The developmental time correlated with the duration of the syllables, the onset variances and the gaps in the syllable. Males with longer and heavier legs produced higher onset, longer verses and longer pauses. The gaps in the syllable amplitude and the width of the thorax correlated with the phase shifting of the hind legs. The immunocompetence rate was positively correlated with the onset and the length of the femur. Females preferred male songs, which contained deep offsets, long periods (syllables), small gaps and long verse durations. The species showed a high degree on sexual dimorphism in morphology and the song parameters. The animals of different populations differed significantly in almost every morphology parameter and a lot of song parameters, while the syllable-to-pause-ration (species-specific) was constant. The females preference of the different sites were similar.

Au cours de leur vie, les animaux doivent sans cesse prendre des décisions qui impactent leur survie et leur succès reproducteur. L’objectif de cette thèse était d’étudier le rôle de deux sources de variabilité dans la prise de décision — la personnalité et l’état émotionnel — en contexte sexuel chez un poisson monogame, le cichlidé zébré. Nos travaux sur la personnalité ont mis en évidence son importance sur la compatibilité comportementale et le succès reproducteur des partenaires. De plus, les individus les plus réactifs se sont ajustés à leur partenaire et ont augmenté leur succès reproducteur. Ceci supporte l’hypothèse d’une plus grande flexibilité de ces individus qui compenseraient ainsi leur faible compétitivité. Les différents profils de personnalité peuvent ainsi être considérés comme des stratégies alternatives. Le maintien de la variabilité interindividuelle pourrait ainsi s’expliquer par le succès équivalent de ces stratégies. Les émotions sont, elles, une cause de variabilité intra-individuelle souvent négligée qui pourrait pourtant représenter une information interne utilisée par l’individu pour prendre ses décisions. En transposant le test cognitif du biais de jugement aux poissons, nous avons pu observer un lien étroit entre leur état émotionnel et la présence/absence du partenaire. Ces résultats suggèrent un rôle des émotions dans les processus d’appariement et interrogent sur leur utilisation dans les prises de décision. Les individus se basent-ils sur leurs émotions pour choisir un partenaire ? Est-ce adaptatif ? À travers l’étude de ces sources de variabilité comportementale, nous avons observé que, loin d’être distribuée aléatoirement, la variabilité était liée à des stratégies décisionnelles et pouvait influencer le succès reproducteur des individus. Il serait donc crucial de la prendre en compte pour appréhender l’évolution des processus décisionnels. / During their lives animals constantly need to make decisions that influence their survival and their reproductive success. The objective of this thesis was to evaluate the role of two variability sources in decision-making — personality and emotional states — in a sexual context in a monogamous fish, the convict cichlid. Our work about personality highlights its importance on pair compatibility and reproductive success. We also observe that reactive individuals adjusted their behaviour to their partner and thus increased their reproductive fitness. This result supports the hypothesis that reactive individuals are more flexible and thus compensate for their weak competitiveness.Personality traits are thus to be considered as co-existing alternative strategies. The maintenance of this inter-individual variability can be results from their equal success on the long run. Emotional states are source of intra-individual variability that has been largely underestimate. However they may represent an internal information used by individuals to make choice. We developed a protocol of cognitive judgment bias test in fish to evaluate their emotional states, and we observed a strong relationship with the presence/absence of the preferred partner. These results suggest that emotions is a key component of pair-bonding and then question how animals use them to make decision. Do they choose a partner based on their emotional states in an adaptive way? Through these different studies, we have shown that behavioural variability is not randomly distributed. On the contrary, it is linked to different strategies and it can influence reproductive success. It is thus crucial to take this parameter into account in order to understand the evolution of decision processes.

Dans ce travail de thèse, nous avons confronté l’explication du fitness model à celle du stéréotype beautiful is good, afin de mieux saisir l’influence de l’attractivité faciale d’un homme sur les préférences d’une femme. Selon le fitness model, une femme interprèterait l’attractivité faciale d’un homme comme l’indice de sa bonne santé (bonne condition génétique), profitable à la survie et au succès reproducteur de la progéniture. Mais selon des travaux en lien avec l’aisance cognitive (prototype, stéréotype beautiful is good), les traits attractifs et l’attention qu’une femme manifeste pour l’attractivité faciale d’un homme n’auraient pas de valeur reproductive, et s’expliqueraient plutôt en termes de facilité de traitement et d’économie cognitive, qui génèrent des réactions positives. Nous avons eu recours à un logiciel de ‘morphing’ afin de créer des visages artificiels d’hommes dont le genre, la correspondance à une moyenne et la symétrie variaient, et les avons fait évaluer par des femmes françaises et marocaines sur différents points : attractivité faciale, santé, revenus, rencontre, partenaire sur le long terme. Les résultats mettent en évidence que l’influence de l’attractivité faciale sur les préférences des femmes n’aurait pas seulement une valeur reproductive, et que l’économie cognitive permise par le recours au stéréotype beautiful is good expliquerait aussi les préférences. / In this work of thesis, we compared the fitness model explanation with the beautiful is good stereotype point of view to better evaluate the influence of men’s facial attractiveness on women preferences. According to the fitness model, a woman would interpret men’s facial attractiveness as an indicator of their good health (good genetic condition), profitable for the offspring’s survival and reproductive success. But according to studies in the field of cognitive ease (prototype, beautiful is good stereotype), the attractive facial features and the attention that a woman pay to men’s facial attractiveness is explained in terms of easy processing and cognitive economy, which generate positive reactions and would have no reproductive value. We used a software of morphing to create artificial men’s faces among which the masculine vs feminine, the averageness and the symmetry were manipulated. After, we submitted these faces to the evaluation of french and moroccan women on several aspects : facial attractiveness, health, income, meeting, long-term mate. The results suggest that facial attractiveness’s influence on women’s preferences would not only have a reproductive value, and that the cognitive economy allowed by the beautiful is good stereotype would also explain the preferences.

Sexual selection can influence the mating system of an organism through multiple mechanisms. These mechanisms result in variation in reproductive success among individuals, and include scramble competition, endurance rivalries, contests, mate choice and cryptic choice, and sperm competition. Understanding the mating system of a species requires the identification of which processes are occurring, and to what degree. In this thesis, I explored the influence of mate choice mechanisms on the mating system of the terrestrial red-legged salamander, Plethodon shermani. I also documented the potential for post-copulatory processes (such as sperm competition and cryptic choice) to influence mating system dynamics. The evolution of mate choice requires (among other factors) variation in the reproductive value of potential mates. This variation is made apparent to choosy individuals through cues. Most animals use multiples cues incorporating many modalities to assess the reproductive quality of potential mates. In Chapter 2, I tested the contribution of two cues (chemical and visual) to mate choice by female P. shermani. I found that a male visual cue ("foot-dancing") increased courtship success. In contrast, delivery of non-volatile pheromones during courtship did not influence courtship success in the laboratory setting, but did affect the duration of one of the courtship stages. In Chapter 4, I identified a tactile cue that was significantly correlated with male reproductive success. Thus, P. shermani females could use at least three modalities to assess the reproductive quality of potential mates. Mate choice can also evolve in males. In Chapter 3, I tested this possibility in P. shermani. I found that males vary the reproductive effort they invest in a particular courtship based on the reproductive value of their partner, indicating male mate choice is occurring. A male invested most when paired with a female with large, well developed ova, and invested less with females that were non-gravid or had small ova. In addition to documenting male mate choice, I showed that the male visual display ("foot-dancing") that affected female mate choice was correlated with male condition, implying foot-dancing may be an honest indicator of male quality. Finally, in Chapter 5, I explored the potential for post-copulatory processes to influence the P. shermani mating system. The opportunity for sperm from multiple males to overlap in the female reproductive tract (i.e., the opportunity for females to mate multiply) is necessary for post-copulatory processes such as cryptic choice and sperm competition. The capacity for long-term sperm storage by females can increase the likelihood that this overlap in sperm from multiple males will occur. I found that females can store viable sperm for at least 9 months and in some cases beyond oviposition. In addition, I documented one female with sperm in her sperm storage organ from a mating that occurred 17 months earlier. Such lengthy sperm storage allows the possibility of sperm from one breeding season to interact with sperm from a subsequent season. Thus, the potential for post-copulatory sexual selection within this salamander system is high. / Graduation date: 2012

The long-term genetic consequences of supportive breeding programs are not well understood. Nevertheless, stocking populations with hatchery-produced fish to compensate for losses of natural production are common practice, for example after constructions of hydroelectric power dams. Hatcheries typically fertilize eggs using ‘mixed-milt fertilizations’, without consideration to natural reproductive behaviours, and hence, natural selective regimes would be altered. Here, a series of experiments with focus on Mhc and mate choice in a population of brown trout (Salmo trutta L.) with a history of long-term stocking are presented. The major histocompatibility complex (Mhc) constitutes of genes coding for antigen presentation in the vertebrate immune system. In addition to the immunological function, Mhc genes might also influence reproductive behaviours such as mate choice. For example, in some species individuals are able to recognize Mhc genotypes of potential mates and to some extent base their mate choice on this information. Here, I address these questions on brown trout. Can the phenomena be observed in brown trout? Could such mechanisms help individuals to avoid inbreeding, or are other mechanisms important? How does the artificial rearing of fish for enhancement of natural populations relate to these issues? The results presented here, in combination with previous work, shows that several factors are important in the process of pair formation in salmonid species. For example, females of the studied population used more than a single criterion when choosing among the available mates Mhc genes and males with certain Mhc genotypes achieved more matings, possibly an effect from increased fighting ability. Further, the population appears to contain an unnatural high level of Mhc variation, and some results indicate that the population might suffer from outbreeding depression at the Mhc. These negative effects are most likely derived from compression of sub-populations after dam-construction, in combination with supportive breeding with no consideration to natural spawning behaviour.

Orientador: Rodrigo Egydio Barreto / Resumo: Os caranguejos-chama-maré são espécies semiterrestres, sociais, que habitam margens de praias abertas, manguezais e marismas, tanto em zonas tropicais como temperadas. Cada indivíduo concentra suas atividades em torno de uma toca, com as fêmeas possuindo os dois quelípodo de mesmo tamanho, enquanto os machos possuem um dos quelípodo hipertrofiado, usados como armas durante interações agressivas para proteção do território ou durante a corte em um movimento característico de display, sendo excelentes modelos para estudos de competição e seleção sexual. Além disso, a escavação do solo para construção de suas tocas acarreta na maior oxigenação do mesmo, altera as condições de drenagem, distribuição de partículas, disponibilidade de matérias orgânicas e nutrientes, sendo assim considerados engenheiros do ecossistema. Portanto, alterações nos manguezais que influenciam na distribuição desse grupo de caranguejos podem intensificar potenciais impactos nessas regiões. A presente tese de doutorado foi dividida em três capítulos. O estudo do capítulo 1 foi realizado em manguezais do litoral centro/sul do Estado de São Paulo, onde investigamos o efeito do sombreamento na distribuição espacial, comportamento e fisiologia de duas espécies de caranguejos-chama-marés: Leptuca leptodactyla e Leptuca urugayensis. Já o estudo do capítulo 2 foi concretizado durante período de doutorado sanduíche no exterior, realizado na Austrália. Nele, examinamos o efeito da migração de espécies de áreas adja... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor