Cavidades naturais constituem um recurso reprodutivo monopolizável, cuja disponibilidade determina a intensidade da competição macho-macho que, por sua vez, pode influenciar os custos do cuidado paternal, pois quanto maior o risco de perda do recurso, menor deve ser a freqüência de forrageio dos machos. Fêmeas do opilião Magnispina neptunus utilizam cavidades naturais como sítios de nidificação, que são monopolizados por machos em um sistema de poliginia por defesa de recursos. Após a oviposição, as fêmeas abandonam os ninhos e todo o cuidado parental é exercido pelos machos. O objetivo deste trabalho foi avaliar o efeito da disponibilidade de ninhos sobre a competição intrassexual e os custos do cuidado paternal em M. neptunus. Dois grupos experimentais foram estabelecidos em laboratório: alta (8 ninhos) e baixa (4 ninhos) disponibilidade de sítios reprodutivos. Cada grupo era composto por sete terrários contendo 12 machos e 12 fêmeas. Apesar da redução dos sítios de nidificação ter reduzido o número de machos detentores de ninhos, o tamanho dos indivíduos não exerceu nenhum efeito sobre o sucesso de monopolização de ninhos. Aparentemente, o pequeno diâmetro de entrada dos ninhos experimentais reduz a importância do tamanho dos machos sobre sua probabilidade de monopolizar um sítio de nidificação. Apenas a residência prévia parece determinar o resultado das disputas entre machos e, portanto, os custos de abandonar os ninhos devem ser altos. De fato, machos guardiões permanecem quase todo o tempo dentro dos seus ninhos em ambos os grupos experimentais, o que aumenta os custos do cuidado. Como conseqüência, o canibalismo filial é freqüente, pois os custos em termos de redução no tamanho da desova são menores do que os benefícios de manter a posse do ninho e dos ovos, que sabidamente aumentam a atratividade dos machos e suas chances de obterem novas desovas / Natural cavities are a reproductive resource that can be monopolized, and their availability determines the intensity of male-male competition, which in turn may influence the costs of paternal care since the higher the risk of loosing the resource, the low should be male foraging frequency. Females of the harvestman Magnispina neptunus use natural cavities as nest site, which are monopolized by males in typical resource defense polygyny mating system. After oviposition, females leave the nests and all parental activities are in charge of males. The goal of this study was to evaluate the effect of nest site availability on the intrasexual competition and the costs of paternal care in M. neptunus. Two experimental groups were established in the laboratory: high (8 nests) and low (4 nests) nest site availability. Each group was composed of seven terraria containing 12 males and 12 females. Although the reduction of in the number of nests sites has indeed reduced the number of males holding nests, male size did not influence the probability of acquiring and maintaining a nest. Apparently, the small diameter of entrance in the experimental nests reduces the importance of male size on their resource holding power. Only previous residence seems to influence the output of agonistic interactions between two males and, therefore, the costs of leaving the nest to forage are likely to be high. In fact, guarding males remain almost all the time inside their nests, which increases the costs of paternal care. As a consequence, filial cannibalism is frequent in both experimental groups because the costs in terms of reduction in clutch size are likely to lower than the benefits of holding a nest containing eggs, which is known to increase male attractiveness and his chance of acquiring additional eggs

Die vorliegende Dissertation verbindet Ergebnisse aus neuroethologischen, verhaltensbiologischen, quantitativ genetischen und genomischen Ansätzen bei Feldgrillen (Gryllus), um neue Erkenntnisse über die Rolle von sexueller Selektion bei Artbildung zu erlangen. Es wird gezeigt dass multivariate Gesangspräferenzen von Grillenweibchen von wenigen Merkmalen abhängen und zwischen Arten ähnlich sind, während sich Männchengesänge in allen Merkmalen unterschieden. Verschiedene Ebenen der Gesangserkennung sind durch unterschiedliche Präferenzfunktionen charakterisiert. Multivariate Präferenzen können also gleichzeitig verschiedene Indikatoren für Paarungspartnerqualität aus den Gesangsmerkmalen erkennen. Eine polygene genetische Architektur der Gesangsmerkmale und der Präferenz wurde beobachtet und weist auf eine eher langsamere Divergenz hin, obwohl gonosomale Vererbung mehrerer Gesangsmerkmale höhere Evolutionsraten zulässt. Starke Kovarianz zwischen den Merkmalen die direkt sexueller Selektion unterliegen und Merkmale, die nicht direkt von Weibchen gewählt werden, zeigen, dass indirekte Selektion teilweise für die markante Divergenz der Gesänge verantwortlich sein könnte, trotz begrenzter Divergenz der Präferenzen. Ferner zeigte ein Artvergleich der multivariaten Gesangsmerkmale, dass die Form der Präferenzfunktion die Ausrichtung der Kovarianzen und damit die erwartete Selektionsantwort der männlichen Gesänge beeinflussen kann. Simulationen ergaben starke Hinweise auf Genfluss zwischen zwei nahverwandten Arten über einen langen Zeitraum . Nur wenige Contigs zeigten hohe genetische Divergenz und hohe Raten nicht-synonymer Polymorphismen. Diese stimmten aber mit Genen überein, die experimentell nachgewiesene Funktionen in neuromuskulärer Entwicklung und im Paarungsverhalten haben. Zusammen zeigen die Ergebnisse das Potential von sexueller Selektion bei der Entstehung und Aufrechterhaltung von reproduktiver Isolation zwischen Arten. / This thesis integrates insights from neuro-ethological, behavioural, quantitative genetics, and genomic approaches in field crickets to provide novel insights in the role of sexual selection in speciation, in particular focusing on speciation with gene flow. It was shown that song preferences depend on few traits and are similar across species while the male song has diverged strongly in all traits. Because the different levels of song recognition are characterized by different types of preference functions, it is conceivable that multivariate preferences can extract various cues for mate quality from different traits simultaneously. A polygenic genetic architecture was found for song traits and preferences, probably limiting divergence rates. However, sex-chromosomal inheritance of some song traits may have allowed for somewhat higher rates. Strong covariance was found between traits that are under sexual selection and traits that are not directly selected by females. This indicates that indirect selection may be responsible in part for striking multivariate divergence in the male calling song despite limited divergence in female preferences. Furthermore, comparing multivariate song traits among species showed that the shape of the preference function can affect the orientation of trait covariance and thereby the selection responses of the male song. Coalescent simulations revealed evidence for a long history of gene flow between two closely related cricket species. Only few contigs with high genetic divergence and high rates of non-synonymous SNPs were found, but many of those that were highly diverged matched genes with experimentally proven functions in neuromuscular development and courtship behavior. Together, these findings underline the potential for sexual selection to drive reproductive isolation.

Pendant de nombreuses années, les femelles ont été décrites comme passives dans les interactions mâles-femelles et ont parfois été négligées dans les études sur les comportements reproducteurs et la communication animale. Pourtant, il est de plus en plus évident que les comportements des femelles influencent ceux des mâles et que les mâles peuvent ajuster leurs comportements de parades aux comportements des femelles. L’objectif principal de cette thèse est de mieux comprendre les signaux que les femelles émettent lors d’interactions avec un mâle dans un contexte de reproduction chez le canari domestique. L’ensemble de mes résultats montre tout d’abord que les femelles utilisent des signaux de parades visuels et acoustiques, c’est-à-dire des postures de sollicitation à l’accouplement et des trilles-spécifiques de femelles, comme une invitation à s’accoupler, mais qu’elles peuvent aussi les utiliser pour inciter le mâle à parader et l’aider à échantillonner la qualité de partenaires potentiels. D’autre part, ces deux signaux n’auraient pas la même efficacité selon le contexte d’émission. Ensuite, il semblerait que les signaux véhiculés par la modalité visuelle pourraient jouer un rôle plus important qu’on ne le pensait jusque-là dans les interactions intersexuelles chez cette espèce. Enfin, cette thèse a aussi pu apporter de nouveaux éléments concernant les préférences des femelles pour les chants de mâles et a montré que les méthodes utilisées en laboratoire pour tester les préférences des femelles étaient fiables et congruentes. Cette thèse permet de contribuer aux recherches grandissantes mettant en évidence le rôle important de la femelle dans les interactions intersexuelles. / Much studies on reproduction and animal communication have considered the female as the passive sex; the role of the female during male-female interactions have often been overlooked. However, there is growing evidence that female behaviours can affect those of the males and that males can adjust their courtships to female behaviours. The aim of this thesis is to understand the signals produced by females during interactions with a male in a reproductive context in the domestic canary. Overall, my results show that females not only use their visual and acoustic signals, the copulation solicitation display and the female-specific trills, as an invitation to copulate but also to incite male to sing as an aid to sample potential mates. Then, these two signals could not have the same efficacy in different contexts of transmission. Moreover, the visual components of the communication seem to be more important than previously thought during intersexual interactions in this species. Finally, this thesis provides new elements about the female preferences for male songs and shows that methods used to test female preferences in laboratory are reliable and congruent. This thesis contributes to the growing number of researches showing that females play an active role in intersexual interactions.

Within the evolutionary framework of sexual selection and parental investment theory, the study employed four experiments to examine the effects of mating and parenting awareness on the perception and assessment of high risk sports. In Study 1, participants were exposed, in random order, five types of pictures---attractive female, regular female, attractive male, regular male, and award winning pictures. After the activation of each of these pictures, participants were asked to respond to pictures depicting high risk sport events. The reaction time to high risk sport events was shortest when men saw attractive female pictures. The same effect was not found in female participants viewing attractive male pictures. Study 2 used the same mating awareness manipulation (attractive female pictures versus other pictures) but also added parenting and child rearing pictures depicting pregnant women or young children with their mothers. The results showed that men's reaction time to high risk sports was shorter when exposed to attractive female pictures than other conditions and was longer when exposed to parenting-related pictures. Study 3 included socialsexual orientation as a covariate and results similar to Study 1 were obtained after controlling for the extraneous influence of socialsexual orientation. Study 4 focused on risk assessment in different domains including entertainment, financial investment, health and social risk. The results showed that men under-assessed risk in the entertainment domain when exposed to attractive female pictures than to award winning pictures. However, the same effect was not found with other risk domains. Overall, the findings support the evolutionary account of risk taking which is sexually selected male attribute as an ornament to attract mating partners and which is reduced when men shift from mating to parenting and child rearing concerns. One practical implication for controlling risk taking behaviors among adolescents is the knowledge that risk taking behavior may be more likely in mixed- than in single-gender social groups. / 李宏利. / Adviser: Lei Chang. / Source: Dissertation Abstracts International, Volume: 70-06, Section: A, page: 1923. / Thesis (doctoral)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (p. 93-118). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in Chinese and English. / School code: 1307. / Li Hongli.

O processo de seleção sexual influencia de forma intensa o sucesso reprodutivo de cada indivíduo. Desde sua formulação teórica durante o século XIX, evidências cumulativas a respeito da poliandria em fêmeas permitiram a ampliação de seu conceito inicial, uma vez constatada que a disputa pela paternidade da prole não se limitava à competição pelo acesso à fêmea, mas poderia também prolongar-se mesmo após a cópula. Durante a década de 1970, essa disputa pós-copulatória entre machos foi formalizada sob o conceito de competição espermática, a qual visa a maximizar o sucesso do esperma de um macho sobre um rival na fertilização dos ovos. Evidências para um número crescente de táxons demonstram que a intensa competição pré e pós-copulatória entre machos é também uma das fontes responsáveis pela evolução e manutenção de táticas alternativas de reprodução dentro de uma mesma espécie, nas quais machos com menor sucesso na monopolização de fêmeas e combate com intraespecíficos adotam comportamentos furtivos para acesso ao sexo oposto, como forma de assegurar algum sucesso reprodutivo. Em muitas espécies, a adoção de táticas alternativas de reprodução são relacionadas não somente às diferenças comportamentais entre os machos, mas também à diversidade fenotípica dentro do mesmo sexo, caracterizada por descontinuidades morfológicas, fisiológicas e de ciclo de vida, conhecida pelo termo ‘dimorfismo intrassexual’. Em lulas da família Loliginidae, a existência de morfos alternativos, denominados machos consort e sneaker, já foi constatada para diversas espécies e é associada a diferenças comportamentais entre eles, principalmente relacionadas à posição de cópula e sítio de deposição de espermatóforos no interior da fêmea. No entanto, a associação entre táticas alternativas de reprodução e dimorfismo intrassexual em machos é praticamente desconhecida, com exceção à espécie Heterololigo bleekeri, para a qual esse dimorfismo tem sido estudado extensivamente ao longo da última década. Nesse contexto, a presente Dissertação de Mestrado teve como principal objetivo investigar a existência de dimorfismo intrassexual masculino em Doryteuthis plei (Blainville, 1823), uma espécie de importância comercial para as regiões Sul e Sudeste do Brasil e para a qual, apesar de evidências indiretas sugerirem sua presença, tal dimorfismo nunca havia sido averiguado. Por meio de análises morfológicas e modelos estatísticos, o primeiro capítulo descreve a existência desse dimorfismo na espécie, o qual foi reconhecido a partir da constatação da presença de duas classes de tamanho de machos sexualmente maduros, caracterizadas pela produção de espermatóforos e espermatângios com morfologias descontínuas. Além disso, espermatângios amostrados de machos das duas classes de tamanho mostraram-se congruentes àquelas implantados nos dois sítios distintos da fêmea, resultado que permitiu associar o dimorfismo intrassexual à adoção das táticas de sneaker e consort na espécie. A partir dessa constatação, o primeiro capítulo explorou ainda o investimento gonadal exibido por machos dimórficos. Os resultados mostraram que machos sneakers apresentavam maiores investimentos relativos em gônadas do que machos consorts, um resultado que se enquadra nos modelos teóricos de “sneaks and guarders” de competição espermática. No entanto, enquanto as premissas teóricas propõem também que machos sneakers devem apresentar maiores investimentos por fêmea, constatamos que, na espécie de estudo, machos sneakers produzem espermatóforos com menor proporção de massa espermática do que machos consorts. Esses resultados, somados a observações comportamentais realizadas ao longo desse trabalho, sugerem que a estratégia adotada por machos sneakers deve estar relacionada ao fracionamento de seu investimento em produtos ejaculatórios, de forma que investimentos menores por fêmea permitiriam a realização de maior número de cópulas. Dando continuidade à caracterização do dimorfismo intrassexual na espécie, análises comparativas entre machos dimórficos com relação a estruturas do sistema reprodutor, tema do segundo capítulo, demonstraram que as diferenças quanto à morfologia funcional de espermatóforos intactos estavam associadas às divergências encontradas quanto à reação espermatofórica, liberação de espermatozoides e morfologia de espermatângios entre machos sneakers e consorts. Além disso, sob o contexto da competição espermática, o segundo capítulo discute como o padrão de reprodução de lulas da família Loliginidae, e.g., a existência de dois sítios de fertilização e diferenças nos intervalos entre cópulas e desovas, resultaria em pressões seletivas divergentes sobre os produtos ejaculatórios de machos dimórficos e influenciaria a evolução e manutenção do dimorfismo intrassexual na espécie. Por fim, o terceiro capítulo aborda a descoberta de machos com espermatóforos e espermatângios com morfologias intermediárias entre os fenótipos de sneakers e consorts, além da questão da diferença de idade entre machos dimórficos. Combinados, os resultados desse capítulo permitiram a proposição de uma hipótese ontogenética sobre a expressão de fenótipos alternativos na espécie, uma questão extremamente inovadora para cefalópodes. Apesar de tratar-se de um campo ainda completamente inexplorado para o grupo, espera-se que esses resultados contribuam para a compreensão dos fatores responsáveis pela expressão sequencial de fenótipos alternativos e pela determinação do dimorfismo intrassexual em lulas / Sexual selection comprises a powerful force that intensively influences the reproductive success of each individual. Since its theoretical formulation in the nineteenth century, cumulative evidence regarding the existence of polyandry in females has expanded its initial concept, once it became clear that offspring paternity disputes were not limited to the competition for female access, but that they could in fact be prolonged even after copulation. In the 1970s, this male post-copulatory dispute was formalized under the concept of sperm competition, which aims at maximizing the success of one male’s sperm over its competitors in the fertilization of females’ eggs. Evidence gathered from a growing number of taxa has shown that intense pre and post-copulatory competition between males is also one of the responsible sources for the evolution and maintenance of alternative reproductive tactics within a species, in which males that are less successful in mate guarding and fighting contests with conspecifics adopt sneaking and opportunistic behaviors as a way to ensure some mating success. In many species, alternative mating tactics are not restricted to behavioral differences between males, being also related to a phenotypic diversity, with discontinuous morphological and physiological traits and distinct life histories between conspecifics, a phenomenon known as intrasexual dimorphism. In loliginid squids, the existence of alternative morphs (sneaker and consort males) has already been reported for several species, and it is has been correlated to behavioral differences, specially related to mating position and spermatophore deposition sites within the female\'s body. However, the association between alternative mating tactics and male intrasexual dimorphism is virtually unexplored, except for the species Heterololigo bleekeri, in which such dimorphism has been extensively studied over the last decade. In this context, the present Master’s Dissertation aimed to investigate the existence of male intrasexual dimorphism in Doryteuthis plei (Blainville, 1823), a squid of commercial importance in southern and southeastern Brazil, and for which such dimorphism has never been investigated, although indirect evidence suggests its existence. Using morphological analyses and statistical models, the first chapter describes the presence of such dimorphism in the species, which was detected based on the identification of two body size classes of sexually mature males, characterized by spermatophores and spermatangia displaying discontinuous morphologies between each other. Moreover, spermatangia sampled from both body size classes were congruent with those implanted on distinct female sites, a result that allowed the association between intrassexual dimorphism and adoption of sneaker and consort mating tactics in the species. Additionally, the first chapter also investigated the gonadal investment from dimorphic males, showing that sneakers exhibited higher investments in gonads than consorts, a result that fits into the theoretical ‘sneaks and guards’ models of sperm competition. However, while theoretical assumptions propose that sneakers should also present larger investments per female, we show that D. plei sneaker males produce spermatophores with lower concentrations of sperm mass than consorts. Combining these results with behavioral observations obtained throughout this study, we suggest that the sneaker strategy might be related to partitioning their ejaculate expenditure into extra mating opportunities, thus investing less per female but more in number of copulations. A further characterization of intrasexual dimorphism in this species was the main subject of the second chapter. Through comparative analyses of reproductive structures from dimorphic males, the results revealed that differences in the structural morphology of intact spermatophores were associated to differences regarding the spermatophoric reaction, spermatozoa release and spermatangia morphology between sneakers and consorts. Furthermore, under the context of sperm competition, the second chapter also provided a discussion on how the reproductive pattern of loliginid squids, e.g., the existence of two sites for fertilization of eggs and differences in the interval between mating and egg-laying, might result in divergent selective pressures on ejaculates from dimorphic males, influencing the evolution and maintenance of intrasexual dimorphism in this species. Finally, the third chapter describes the discovery of males that produced spermatophores and spermatangia displaying intermediate morphologies between both sneaker and consort phenotypes, and age differences reported for dimorphic males in the species. Combined, these results allowed the formulation of an ontogenetic hypothesis regarding alternative phenotype expression, which is extremely innovative for cephalopods. Although this hypothesis comprises a completely unexplored field for this group, it is highly expected that these results might contribute to the further understanding of possible factors that may be responsible for the sequential expression of alternative phenotypes, and ultimately for the determination of intrasexual dimorphism in squids

La sélection sexuelle est une composante de la sélection naturelle qui génère des différences de succès reproducteur entre les individus par le filtre de la reproduction, et influence donc la transmission intergénérationnelle des gènes. Dans le cadre de cette thèse, l’effet de la variabilité de l’environnement hydraulique sur la sélection sexuelle chez la truite commune a été étudié à différentes échelles : intra- et inter-populationnelle. Des méthodes nouvelles permettant de mieux appréhender l’investissement reproducteur, ainsi que de décomposer l’effet des traits sur la fitness des individus en fonction des différentes étapes de la sélection sexuelle, ont été mises au point. Les expériences réalisées en milieux naturel et semi-naturel indiquent que la variabilité environnementale n’affecte pas le choix d’habitat de reproduction par les femelles, mais peut affecter l’investissement reproducteur dans la compétition par exemple, ainsi que les flux de gènes entre des populations génétiquement distinctes. Ces résultats permettent une première projection de l’évolution de la sélection sexuelle dans le contexte du changement climatique qui prédit l’augmentation de la variabilité hydrologique en zone tempérée. / As a component of natural selection, sexual selection produces variation in reproductive success throughout the reproductive period, and therefore impacts genes transmission between generations. During this PhD, the effect of variation in hydraulic environment on sexual selection in brown trout was investigated at both within and between populations scales. New approaches to improve estimation of reproductive investment, as well as models to decompose the effect of traits on individual fitness at each stage of sexual selection, were developed. Experiments in natural and semi-natural environments indicate that environmental variation does not impact reproduction habitat choice by females, but it can modify reproductive investment in some populations, as well as it can control gene flow between genetically distinct populations. These results help to understand the evolution of sexual selection in the broad context of increasing stochastic variations of river systems hydrology as predicted by climate change models in temperate areas.

Para avaliar a quantidade ótima de energia e recursos a ser investida em reprodução, um animal deve não só acessar informações sobre sua própria condição corporal, como acessar também informações sobre coespecíficos presentes no ambiente em que vive. Este trabalho investigou essas duas vias (endógena e exógena) de obtenção de informação. Utilizando como organismo modelo a aranha Paratrechalea ornata (Trechaleidae), uma espécie em que os machos produzem presentes nupciais, este estudo investigou: (a) se machos investem mais tempo de busca quando na presença de pistas químicas de fêmeas virgens; (b) se machos aumentam ou diminuem o investimento na produção do presente nupcial quando há pistas da presença de machos competidores; (c) se restrições alimentares impõem efeitos de curto e longo prazo sobre o comportamento de construção de presentes nupciais. Machos mostraram preferência por locais com pistas da presença de fêmeas, mas não diferenciaram pistas de fêmeas virgens e copuladas. Diante de pistas da presença de um macho competidor, machos produziram presentes de menor qualidade, com menos seda. Por fim, restrições alimentares provocam efeitos de curto e longo prazo no comportamento reprodutivo dos machos, diminuindo a frequência de produção do presente nupcial e o tamanho do presente construído. Conjuntamente, os três experimentos realizados mostram que machos de P. ornata utilizam tanto informações exógenas quanto endógenas para ajustar seu investimento em reprodução. A combinação das informações obtidas deve aumentar a eficiência no gasto de energia, maximizando o sucesso reprodutivo dos machos sem que isso prejudique a manutenção de seu organismo / To evaluate the optimal amount of energy and resources to be invested in reproduction, animals should not only obtain information about their own body condition, but they should also obtain information about conspecifics in the environment where they live. This study investigated these two ways (endogenous and exogenous) of acquiring information. Using as model organism the spider Paratrechalea ornata (Trechaleidae), a species in which males produce nuptial gifts, this study investigated: (a) if males invest more time searching for sexual partners in the presence of chemical cues of virgin females; (b) if males increase or decrease the investment in nuptial gift construction in the presence of chemical cues of competitor males; (c) if food deprivation imposes short- and long-term effects on nuptial gift construction. Males showed a preference for sites with cues of females, but they did not discriminate cues of virgin from cues of copulated females. When males detected cues of a male competitor, they produced lower quality gifts, with less silk. Finally, food deprivation imposed both short- and long-term negative effects on male reproductive behavior, decreasing the frequency of nuptial gift construction and also the size of the gift. Together, the three experiments show that males of P. ornata use both exogenous as endogenous information to adjust their investment in reproduction. The combination of information obtained may increase the efficiency in energy use, maximizing male reproductive success without compromising self maintenance

O processo de seleção sexual influencia de forma intensa o sucesso reprodutivo de cada indivíduo. Desde sua formulação teórica durante o século XIX, evidências cumulativas a respeito da poliandria em fêmeas permitiram a ampliação de seu conceito inicial, uma vez constatada que a disputa pela paternidade da prole não se limitava à competição pelo acesso à fêmea, mas poderia também prolongar-se mesmo após a cópula. Durante a década de 1970, essa disputa pós-copulatória entre machos foi formalizada sob o conceito de competição espermática, a qual visa a maximizar o sucesso do esperma de um macho sobre um rival na fertilização dos ovos. Evidências para um número crescente de táxons demonstram que a intensa competição pré e pós-copulatória entre machos é também uma das fontes responsáveis pela evolução e manutenção de táticas alternativas de reprodução dentro de uma mesma espécie, nas quais machos com menor sucesso na monopolização de fêmeas e combate com intraespecíficos adotam comportamentos furtivos para acesso ao sexo oposto, como forma de assegurar algum sucesso reprodutivo. Em muitas espécies, a adoção de táticas alternativas de reprodução são relacionadas não somente às diferenças comportamentais entre os machos, mas também à diversidade fenotípica dentro do mesmo sexo, caracterizada por descontinuidades morfológicas, fisiológicas e de ciclo de vida, conhecida pelo termo ‘dimorfismo intrassexual’. Em lulas da família Loliginidae, a existência de morfos alternativos, denominados machos consort e sneaker, já foi constatada para diversas espécies e é associada a diferenças comportamentais entre eles, principalmente relacionadas à posição de cópula e sítio de deposição de espermatóforos no interior da fêmea. No entanto, a associação entre táticas alternativas de reprodução e dimorfismo intrassexual em machos é praticamente desconhecida, com exceção à espécie Heterololigo bleekeri, para a qual esse dimorfismo tem sido estudado extensivamente ao longo da última década. Nesse contexto, a presente Dissertação de Mestrado teve como principal objetivo investigar a existência de dimorfismo intrassexual masculino em Doryteuthis plei (Blainville, 1823), uma espécie de importância comercial para as regiões Sul e Sudeste do Brasil e para a qual, apesar de evidências indiretas sugerirem sua presença, tal dimorfismo nunca havia sido averiguado. Por meio de análises morfológicas e modelos estatísticos, o primeiro capítulo descreve a existência desse dimorfismo na espécie, o qual foi reconhecido a partir da constatação da presença de duas classes de tamanho de machos sexualmente maduros, caracterizadas pela produção de espermatóforos e espermatângios com morfologias descontínuas. Além disso, espermatângios amostrados de machos das duas classes de tamanho mostraram-se congruentes àquelas implantados nos dois sítios distintos da fêmea, resultado que permitiu associar o dimorfismo intrassexual à adoção das táticas de sneaker e consort na espécie. A partir dessa constatação, o primeiro capítulo explorou ainda o investimento gonadal exibido por machos dimórficos. Os resultados mostraram que machos sneakers apresentavam maiores investimentos relativos em gônadas do que machos consorts, um resultado que se enquadra nos modelos teóricos de “sneaks and guarders” de competição espermática. No entanto, enquanto as premissas teóricas propõem também que machos sneakers devem apresentar maiores investimentos por fêmea, constatamos que, na espécie de estudo, machos sneakers produzem espermatóforos com menor proporção de massa espermática do que machos consorts. Esses resultados, somados a observações comportamentais realizadas ao longo desse trabalho, sugerem que a estratégia adotada por machos sneakers deve estar relacionada ao fracionamento de seu investimento em produtos ejaculatórios, de forma que investimentos menores por fêmea permitiriam a realização de maior número de cópulas. Dando continuidade à caracterização do dimorfismo intrassexual na espécie, análises comparativas entre machos dimórficos com relação a estruturas do sistema reprodutor, tema do segundo capítulo, demonstraram que as diferenças quanto à morfologia funcional de espermatóforos intactos estavam associadas às divergências encontradas quanto à reação espermatofórica, liberação de espermatozoides e morfologia de espermatângios entre machos sneakers e consorts. Além disso, sob o contexto da competição espermática, o segundo capítulo discute como o padrão de reprodução de lulas da família Loliginidae, e.g., a existência de dois sítios de fertilização e diferenças nos intervalos entre cópulas e desovas, resultaria em pressões seletivas divergentes sobre os produtos ejaculatórios de machos dimórficos e influenciaria a evolução e manutenção do dimorfismo intrassexual na espécie. Por fim, o terceiro capítulo aborda a descoberta de machos com espermatóforos e espermatângios com morfologias intermediárias entre os fenótipos de sneakers e consorts, além da questão da diferença de idade entre machos dimórficos. Combinados, os resultados desse capítulo permitiram a proposição de uma hipótese ontogenética sobre a expressão de fenótipos alternativos na espécie, uma questão extremamente inovadora para cefalópodes. Apesar de tratar-se de um campo ainda completamente inexplorado para o grupo, espera-se que esses resultados contribuam para a compreensão dos fatores responsáveis pela expressão sequencial de fenótipos alternativos e pela determinação do dimorfismo intrassexual em lulas / Sexual selection comprises a powerful force that intensively influences the reproductive success of each individual. Since its theoretical formulation in the nineteenth century, cumulative evidence regarding the existence of polyandry in females has expanded its initial concept, once it became clear that offspring paternity disputes were not limited to the competition for female access, but that they could in fact be prolonged even after copulation. In the 1970s, this male post-copulatory dispute was formalized under the concept of sperm competition, which aims at maximizing the success of one male’s sperm over its competitors in the fertilization of females’ eggs. Evidence gathered from a growing number of taxa has shown that intense pre and post-copulatory competition between males is also one of the responsible sources for the evolution and maintenance of alternative reproductive tactics within a species, in which males that are less successful in mate guarding and fighting contests with conspecifics adopt sneaking and opportunistic behaviors as a way to ensure some mating success. In many species, alternative mating tactics are not restricted to behavioral differences between males, being also related to a phenotypic diversity, with discontinuous morphological and physiological traits and distinct life histories between conspecifics, a phenomenon known as intrasexual dimorphism. In loliginid squids, the existence of alternative morphs (sneaker and consort males) has already been reported for several species, and it is has been correlated to behavioral differences, specially related to mating position and spermatophore deposition sites within the female\'s body. However, the association between alternative mating tactics and male intrasexual dimorphism is virtually unexplored, except for the species Heterololigo bleekeri, in which such dimorphism has been extensively studied over the last decade. In this context, the present Master’s Dissertation aimed to investigate the existence of male intrasexual dimorphism in Doryteuthis plei (Blainville, 1823), a squid of commercial importance in southern and southeastern Brazil, and for which such dimorphism has never been investigated, although indirect evidence suggests its existence. Using morphological analyses and statistical models, the first chapter describes the presence of such dimorphism in the species, which was detected based on the identification of two body size classes of sexually mature males, characterized by spermatophores and spermatangia displaying discontinuous morphologies between each other. Moreover, spermatangia sampled from both body size classes were congruent with those implanted on distinct female sites, a result that allowed the association between intrassexual dimorphism and adoption of sneaker and consort mating tactics in the species. Additionally, the first chapter also investigated the gonadal investment from dimorphic males, showing that sneakers exhibited higher investments in gonads than consorts, a result that fits into the theoretical ‘sneaks and guards’ models of sperm competition. However, while theoretical assumptions propose that sneakers should also present larger investments per female, we show that D. plei sneaker males produce spermatophores with lower concentrations of sperm mass than consorts. Combining these results with behavioral observations obtained throughout this study, we suggest that the sneaker strategy might be related to partitioning their ejaculate expenditure into extra mating opportunities, thus investing less per female but more in number of copulations. A further characterization of intrasexual dimorphism in this species was the main subject of the second chapter. Through comparative analyses of reproductive structures from dimorphic males, the results revealed that differences in the structural morphology of intact spermatophores were associated to differences regarding the spermatophoric reaction, spermatozoa release and spermatangia morphology between sneakers and consorts. Furthermore, under the context of sperm competition, the second chapter also provided a discussion on how the reproductive pattern of loliginid squids, e.g., the existence of two sites for fertilization of eggs and differences in the interval between mating and egg-laying, might result in divergent selective pressures on ejaculates from dimorphic males, influencing the evolution and maintenance of intrasexual dimorphism in this species. Finally, the third chapter describes the discovery of males that produced spermatophores and spermatangia displaying intermediate morphologies between both sneaker and consort phenotypes, and age differences reported for dimorphic males in the species. Combined, these results allowed the formulation of an ontogenetic hypothesis regarding alternative phenotype expression, which is extremely innovative for cephalopods. Although this hypothesis comprises a completely unexplored field for this group, it is highly expected that these results might contribute to the further understanding of possible factors that may be responsible for the sequential expression of alternative phenotypes, and ultimately for the determination of intrasexual dimorphism in squids

Successful captive-breeding and re-introduction programs must have the ability to breed a surplus of genetically suitable animals for release into the wild. Unfortunately, many individuals in captive breeding programs often do not reproduce even when they are apparently healthy and presented with genetically appropriate mates. Mate choice can affect multiple parameters of reproductive sperformance, including mating success, offspring production, survival, and fecundity. We investigated the role of mate preference and personality on the reproductive performance of male and female giant pandas (Ailuropoda melanoleuca) as measured by intromission success and litter production. We conducted these studies on giant pandas at the China Conservation and Research Center for the Giant Panda (Bifengxia, Sichuan, China.) from February-May 2011, 2012, and 2013. In Chapter 2, we compared reproductive performance between individuals mated with preferred and nonpreferred males of the focal female (female preference), the focal male (male preference), and mutual mate choice perspective. There were four types of reproductive pairings in our mutual mate choice analyses: females and males that preferred each other (P-P), females that preferred the male but the male did not prefer the female (P-NP), females that did not prefer the male but the male preferred the female (NP-P), and females and males that did not prefer each other (NP-NP). Pairing giant pandas with a preferred partner increased the probability of intromission success and producing a cub. Of the 25 females mated to a preferred partner, 72% had successful intromission, 64% produced cubs, and 52% reared their own cubs versus 31%, 12%, 12% for females mated to their nonpreferred partner (N = 16). Male giant panda mate preference showed similar results. Of the 24 males that were mated with their preferred females, 75% had successful intromission, 77.8% produced cubs, and 92.9% produced cubs that were maternally reared versus 31%, 60%, 66.7% for males mated with their nonpreferred females (N = 16). There was a statistically significant difference in intromission success and cub production for P-P pairings versus NP-NP pairings. Of the twelve P-P mate dyads 83% had successful intromission, 90% produced cubs, and 88.9% had mothers rear their cubs. Of the four P-NP mate dyads 50% had successful intromission, 50% produced cubs, and 100% had the mother rear their cub. Of the seven NP-P mate dyads 57% had successful intromission, 50% produced cubs, and 100% had the mothers rear their cubs. Of the three NP-NP mate dyads 0% had successful intromission resulting in 0% producing cubs and having mother-rear cubs. In addition, we took into account various life and breeding history factors that may have affected reproductive performance such as birth location, rearing, previous sexual history with the opposite sex and familiarity status directly prior to breeding. Mate pairings that were familiar with each other as measured by successfully producing a cub in the past, had increased intromission success. Females mated to heavier males had more intromissions and produced more cubs than females mated to smaller males. In Chapter 3 and 4, we investigated the effect of personality on reproductive performance measurements. Recently, personality of individual animals has been implicated in the failure or success of captive management and breeding of threatened and endangered species. Measurements of personality included novel object tests (where behaviors of individual giant pandas were scored toward a novel object for one hour) and keeper surveys (where the primary keeper rated giant pandas on 23 adjectives describing personality); both measures significantly correlated with variation in long-term and specific mating dyad reproductive performance. In Chapter 3 we evaluated the effect of personality on long-term reproductive performance. Our results show that for both male and female giant pandas, `fearful' individuals had lower natural mating success and cub production. In addition, `aggressive' female giant pandas had increased natural mating success but decreased cub production. Males did not show these relationships between `aggressive' personality types and reproductive performance. Female giant pandas that were labeled as `aggressive' had higher frequencies of positive mating behaviors but `fearful of conspecifics' females had lower frequencies. Males labeled `fearful of conspecifics' and with high `playful-clever' component scores had a lower frequency of positive mating behaviors. In Chapter 4 we further investigated the effects of personality within a specific mating dyad. Recent studies suggest that mate compatibility within personality types can improve reproductive performance measurements such as mating success, offspring survivorship, and offspring quality. We investigated the effect of personality compatibility on reproductive performance through analyzing mate dyad similarity in personality (similar versus dissimilar), specific personality combinations, and relative personality scores (male scores higher or lower than female scores). The specific personality combinations were: females and males that were both low on the personality component (L_L), females were low but males were high (L_H), females were high but males were low (H_L), and females and males were both high (H_H). Our results suggest that giant pandas appear to be assortatively mating based on aggressive, fearful, and stereotypical-excitable personality traits. Mate dyads that were dissimilar on the stereotypical-excitable component score were more likely to have successful intromission than pairs that were similar. L_H mate dyads on the aggressive and stereotypical-excitable personality traits had increased intromission success and cub production than all other possible personality combinations. L_L on fearfulness had higher intromission success but not higher cub production than all other possible personality combinations. Mate dyads composed of males ranked high on the aggressive component relative to the female resulted in higher reproductive performance and cub production. In captive breeding programs, mates are traditionally selected solely on the basis of genetic parameters to minimize loss of genetic diversity and inbreeding coefficients. Our results suggest that integrating genetic with behavioral measures of preference, breeding history factors, and personality would increase the reproductive output of the giant panda captive-breeding program. We stress the importance of considering husbandry practices to accommodate personality traits and ultimately increase reproductive performance in the captive population while simultaneously maintaining both genetic and behavioral diversity.

<p>Sexual selection arises through variation in reproductive success. This thesis investigates different aspects important in sexual selection, namely nest building, sperm competition, paternity and paternal care, and their mutual interrelationships. In the studied species, the sand goby (<i>Pomatoschistus minutus</i>) and the common goby (<i>Pomatoschistus microps</i>), sperm competition did arise when small males, so called sneakers, sneaked into other males nests and released sperm. They seemed to use female behaviour as their prime cue for a sneaking opportunity. However, also nest-holders, both with and without eggs, were found to fertilize eggs in the nests of other males.</p><p>Clearly, nest-holding males tried to prevent other males from spreading their sperm in their nests, since they showed aggression towards such males. A nest building experiment indicated that the small nest-openings found in the sneaker male treatment were sexually selected through protection against sneaking or by female choice. Yet, no behavioural or genetical support for the hypothesis that the nest functions as a physical or visual defence, or that sneaker males prefer to sneak upon nests with wide nest-openings, were found in the other studies. Still, individual nest-holding males showed a higher mucus preparation effort inside the nest in the presence of a sneaker male than when alone. In close relatives, such mucus contains sperm, suggesting an importance in sperm competition. However, the mucus may also have pheromone and anti-bacterial functions and may constitute a mating effort, as found in other gobies. Both a behavioural and a mate choice experiment suggested that the males were not less eager to spawn in the presence of a sneaker male.</p><p>Sneak intrusion did not affect nest defence, fanning or filial cannibalism, nor had paternity an effect on filial cannibalism. This and various life history aspects, together with the fact that the parasitic male only fertilized a fraction of the clutches, would predict females to ignore sneaker males. This was also the case, as the presence of sneaker males was found not to affect female spawning decision. Still, several females spawned in two nests, which coincided with parasitic spawnings, suggesting a cost of disturbance for the females and thus a substantial cost to the nest-holding males in terms of lost mating success. However, females paid attention to other traits in their choice of mate since spawning was associated with sand volume of the nest, but not with nest-opening width. Also, female (but not male) courtship was correlated with partial clutch filial cannibalism, indicating that females are able to anticipate future male cannibalism.</p><p>In a partial correlation of nest opening, sand volume, male courtship display, displacement fanning and male size, a large number of traits were correlated both positively and negatively with regard to how we may expect them to be appreciated by females. For instance, males which fan well also build large nests or display intensely (but not both). Together with all the other results of this thesis, this shows the entangled selection pressures working on breeding animals, as well as the different male and female tactics employed to maximize their reproduction.</p>