Adaptation to local environments via natural selection is a powerful mechanism for population divergence and likely one of the primary causes of speciation. To understand how specific habitats shape local adaptation, it is helpful to study closely-related populations from widely differing ecosystems that have not had sufficient time to diverge by genetic drift. Throughout the following chapters I examine the distribution of morphological, behavioral, and reproductive phenotypes within and between two subspecies of the swamp sparrow. These two populations, the tidal salt marsh endemic Melospiza georgiana nigrescens and the nominant inland subspecies, M. g. georgiana were incompletely isolated from each other following the retreat of the Wisconsin glaciation. Since that time the increased nest predation, temperature, season length, salinity and tidal flow of the coastal marshes relative to inland wetlands has resulted in a number of adaptations among coastal sparrows due to natural selection, sexual selection, and phenotypic plasticity. Specifically I examine the habitat preferences of the coastal plain swamp sparrow, the difference in clutch size between the two subspecies, the rates of extrapair fertilization relative to male quality, the ecosystem-specific interactions between natural and sexual selection on plumage badges, and the role of conspecific attraction in nest placement. The environmental differences of the tidal salt marsh have played strong roles in the local adaptation and divergence of coastal plain swamp sparrows from their freshwater ancestors. Many of these divergent mechanisms may be similar among other tidal marsh endemics, although some (especially those related to sexual selection) may be specific to the swamp sparrow. In general, however, we see that the added environmental challenges of tidal ecosystems strongly alter selection regimes on a terrestrial vertebrate inhabiting this dynamic ecotone. The swamp sparrow system can further increase our understanding of how the interplay between environmental resources, sexual selection, and natural selection affects the local adaptations leading to evolutionary divergence. / Ph. D.

Humor is likely to serve as signals of fitness in potential partners. Less is known about how different styles of humor affect partner attractiveness. This study aimed to test the attractiveness of the four different humor styles proposed by Martin et al. (2003) categorized according to being benign (affiliate, self-enhancing) or detrimental (aggressive, self-defeating). Participants were presented with a series of potential partners, much like on a dating site. Each partner was described by a portrait picture and a vignette, which included examples of one of the four humor styles. The participants’ task was to rate a number of items about partner preference (date, intercourse, shortand long-term relationships) and mate value (intelligence, health, social status and parenting skill). A total of 170 women and 81 men between 18-40 years of age completed the experiment. The results showed significant effects on all measurements of partner interest and mate value for women with the aggressive humor style being rated as less attractive and lower in mate value than the other humor styles. For men there was a significant effect on two measurements on mate value (social status, parenting skill), showing that the self-defeating style was rated less attractive. The results support the notion that humor is used as a fitness signal, that this is used to a substantially greater extent by women, and that women find the aggressive humor style to be particularly unattractive in potential partners.

Sexually selected ornaments are among the most spectacular traits in nature. Indeed, the extreme costs associated with producing sexual traits seem to play a crucial role in their evolution by enforcing honest levels of advertisement: only males with high levels of acquired resources (or high ‘condition’, as it is known in the literature) can afford to produce extravagant signals, a phenomenon which maintains signal reliability in a constant environment. In my thesis I examine many implications of this condition-dependent model of ornament and preference evolution for variation in age-dependent allocation to sexual signals and other life history traits. In Chapter 1, I review theoretical implications of condition-dependent signalling for life history and sexual selection theory. I note that a universal cost of expenditure in sexual advertisement is metabolic in nature: metabolites used to fund ornament expression are by definition unavailable to other life history traits that compete for a limited resource pool. This universal constraint on expenditure does more than maintain honesty (as noted above), however: the reliance of sexual displays on high levels of nutrient acquisition may help maintain genetic variation in sexual signals that would otherwise be eroded by strong mate choice, and without which the selective basis for good-genes choice would disappear. Three mechanisms in particular probably help to maintain genetic variation in acquisition. 1) Because acquiring resources and converting them efficiently to useful forms depends on the high function of many biochemical pathways, condition is undoubtedly highly polygenic, which slows the erosion of genetic variation under strong directional selection by females (especially in the presence of epistatic interactions). 2) The highly polygenic nature of condition also presents a large target for mutation, which continually restores variation at the loci under selection. 3) The many loci underlying condition may also be particularly sensitive to environmental heterogeneity in time or space. By favouring the most ornate males, females acquire high performing genes for their offspring, regardless of the precise allele combinations that have conferred the ability to acquire resources. Selection on specific alleles is liable to fluctuate over time or space whenever allelic performance is strongly context-specific. I close by noting the considerable challenges in advancing research on sexual selection and life history allocation, including the fact that two key processes central to life history (acquisition and allocation) are latent variables that interact in complexways and are intrinsically difficult to measure empirically. In the remainder of my thesis I conduct a series of experiments involving decorated crickets, Gryllodes sigillatus, which are useful models for studying life history because they enable precise measurement of male reproductive effort. Male G. sigillatus face important allocation decisions owing to the highly polyandrous nature of females, and the substantial costs involved in signalling and mating. Chapter 2 examines sex differences in age-dependent reproductive effort as a function of diet and development stage. I reared outbred crickets using four combinations of diet nutritional quality, and studied the effects of these combinations on male and female reproductive effort (calling effort in males and fecundity in females) and longevity. While I expected males to be more sensitive than females to variation in diet and developmental changes in its quality, I actually observed the opposite: males in all treatments increased calling effort over time, exhibiting consistently positive covariance between calling effort and longevity across treatments. By contrast, the relationships between female reproductive effort and longevity changed dramatically across treatments, and females who lived to intermediate ages had the highest fecundity. Although my results support sex-specific selection on life history allocation over time, a compelling additional explanation for my findings relates to the strategic role of calling for achieving male fitness. In the absence of positive feedback from potential mates, perhaps male allocation to sexual advertisement is careful and only increases gradually as a function of accumulating metabolic resources and increasing risk of intrinsic mortality. Alleles underlying condition are expected to be particularly sensitive to environmental heterogeneity. While this sensitivity may help maintain additive variation in male quality (which is essential for the sustenance of adaptive good-genes mate choice, as noted in Chapter 1), too much environmental sensitivity could also underiii mine the signal value of the male trait. For example, if there are strong genotypeby- environment interactions (GEIs) for sexual advertisement, in a rapidly changing environment females risk favouring a male whose alleles are no longer best suited to current conditions. This problem is particularly pressing for animals like crickets where males exhibit a behaviourally plastic sexual display (such as calling), and so may dynamically adjust signalling effort over time. In Chapter 3, I used inbred lines of decorated crickets to quantify age and diet dependent genetic variation in male signalling. I demonstrate that while genetic correlations across diets were quite strong for morphological traits, correlations between measures of the male sexual trait rapidly approached zero as I increased the distance in time (i.e., across widely spaced ages) or diet (i.e., comparing more dissimilar dietary histories) between samples. While extrapolating from my laboratory experiments to nature is difficult, my findings nevertheless cast doubt on the value of behaviourally dynamic signals (such as cricket calls) for reliably indicating genetic quality in realistically complex environments. In Chapter 4 I used physiological assays to evaluate factors affecting metabolite storage and use over time in decorated crickets. I manipulated the acquisition ability of all males using artificial diets that varied linearly in nutrient quality, and manipulated access to female mates over the course of the second week of adult life. By sacrificing crickets at key stages before and after manipulating the diet and social environment, I was able to estimate changes in stored metabolites, and relate these changes to calling effort and longevity. During the first week of adulthood (in the absence of females), higher diet quality significantly increased calling effort and storage of lipid, glycogen, and carbohydrate (but not protein). The presence of females increased both the probability of calling and the amount of calling during the second week, whereas diet quality only improved calling effort. By the end of the second week, calling effort had decreased, even by high quality males in the presence of females, suggesting a depletion of resources. Furthermore, the loss of condition during week 2 covaried with calling effort during the previous week irrespective of diet. Males who started the second week in high condition lost more glycogen and carbohydrate than rivals; meanwhile, lipid accumulation covaried positively with calling effort during week 2. The contrasting patterns of storage and use for lipids compared to the ‘quick-release’ metabolites (glycogen and carbohydrates) affirms starkly distinct functions for the different storage components, and underlines the importance of specific physiological measures in life history research. Finally, in the general discussion, I attempt to synthesise my thesis’s contributions to the study of life history trade-offs involving behavioural sexual displays.

The aim of this study was to obtain an understanding of the basis to female mating decisions in the Chinese rose bitterling (Rhodeus ocellatus). Bitterling have a resource-based mating system that involves the female laying her eggs inside the gills of a freshwater mussel. Male bitterling perform elaborate courtship behaviour and are territorial and aggressively guard mussels in their territory from other territory holders and non-territorial males. Using a series of laboratory experiments it was shown in this study that females were choosy over the males they mated with, but females were not congruent in their preferences. Female mate preferences correlated positively with offspring growth rates and survival during early development. Female mate choice did not correspond with male dominance, and there may be an intersexual conflict between female mate preferences and male dominance as a result. Females tended to prefer males with functionally dissimilar MHC alleles. MHC alleles may influence male odour cues, and females showed a preference for mussels in which the sperm of multiple males had been released, possibly indicating that females use odour cues associated with sperm release in mating decisions. Bitterling show an innate preference for the colour red in a foraging context and there may be a receiver bias for red nuptial colouration in female mating preferences. Despite a significant role for mate preferences, direct (oviposition) mating preferences were shown to be more important in the mating system. Choice of oviposition sites has both immediate (survival) consequences for offspring, as well as longer-term fitness effects.

<p>Natural and sexual selection and sexual conflict are forces shaping the evolution of reproductive behaviour, while constrained by factors like environment, physiology and life-history trade-offs. Parental care is costly both in terms of time and energy. In fish, filial cannibalism is a strategy for caring males to compensate for some of the energy loss. Human impact like eutrophication also alters the basics for animals living in that environment. It is fundamental to any species to adjust its behaviour to a changing environment. Studying sand goby males, I found trade-offs both regarding parental care allocations, like ventilation vs. predator defence, and investment in present vs. future reproductive success. Paternal sand gobies exposed to water with low oxygen levels increased their fanning effort but did not compensate by eating more eggs, even though an increased current parental effort should affect future reproductive success negatively. Investigating if patterns of filial cannibalism change with time of season, I found no correlation. Theory predicts that it should pay more to eat eggs early, when future mating potential is higher than late in the season. However, as early hatching fry are likely to gain higher fitness through larger size the next breeding season, this may provide an opposing selection pressure. In species with male care the only way a female can affect the level of post-spawning care is by choosing a good mate. A female preference to spawn in nests that already contain eggs of other females has been interpreted as a means to avoid filial cannibalism through a dilution effect or to decrease the costs of search time. Yet, in my study females did not avoid filial cannibalism by preferring large clutches to small ones. Oxygenation of the eggs might be a key factor, since both large and small females preferred spawning in nests with small clutches. Thus, as in most animals, trade-offs clearly govern the reproductive behaviour of sand gobies.</p>

Dans un contexxte de sélection sexuelle, les signaux émis par les mâles sont censés refléter honnêtement leur condition. Etant donné que la condition est un concept multifactoriel, il a été propposé que les différentes composantes des signaux sexuels reflètent différents aspects de la condition de l'émetteur (Hypothèse des messages multiples). Ma thèse a pour but de tester la condition-dépendance des signaux sexuel et l'hypothèse des messages multiples en manipulant différents aspects de la condition mâle ; et d'étudier les moyens de contourner un système de signalement honnête par des tactiques de reproduction alternatives. Nous avons conduit ces expériences chez Hyla arborea, espèce chez laquelle les mâles émettent des signaux comprenant des composantes accoustiques et visuelles impliquées dans le choix du partenaires sexuel. Nos résultats suggèrent que le taux de chant intra-bout, une propriétédynamique, est un indicateur de la condition actuelle, alors que la fréquence dominante, une prpriété statique du chant, semble indépendante de la condition actuelle mais liée à la condition passée. Les composantes visuelles du signal sont indépendantes des variations du statut mutirtionnel à court terme mais pourraient être des indicateurs de la condition passée. L'adoption d'une tactique satellite dépend plus de la condition passée que de l'actuelle. Plusieurs composantes du signal sont liées à différents aspects de la condition du mâle, ce qui supporte l'hypothèsedes messages multiples. CEpendant, les relations entre les composantes et les aspects de la condtion sont faibles et nous poussent à considérer également la dynamique évolutive des systèmes de signalements. / In a sexual selection context, signals displayed by males are supposed to reflect honestly their condition. Given that condition is a mutlifactorial concet, it has been propposed that the multiple compopnenets often involved in sexual signal reflects differents aspect of emitter's condition (multiple messages hypothesis). My thesis aimed at testing the condition-dependance of sexual signals and the muliple messages hypothesis by manipulating different aspects of male condition ; and at investigating ways to circumvent an honest signalling systems through alternative reproductive tactics. We conduced these experiments on the European treefrog (Hyla arborea), a species in wich males display signals with both accoustic ansd visual components used by females during mate choice. Our results suggest that the within-bout call rate, a dynamic call property, is a reliable indicator of current condition while call dominant frequency, a static call property, seems to be independant from current conditions but is linked to past condition. Visual signal components are independant from variations in nutritional status on short term but are linked to male condition in the field and may be indicators of past condition. The adoption of satellite tactic depends more on past condition than on current condition.. As several signal components are related to the emitter'scondition and seem to be independant upon distinct aspects of this condition, our results mainly support the multiple messages hypothesis. However, the weak correlations betxeen signal components and condition aspects found in this study highlight the necessity to consider also the evolutionary dynamics of signalliings systems.

In this dissertation, I report new information that is necessary for future mating system studies in a little studied species, the marbled salamander (Ambystoma opacum). I studied female mating behavior, sexual selection, and the consequences of polyandry for individual females and salamander populations. I also compared the performance of several statistical approaches for analyzing genetic mating system data. The first chapter summarizes the characteristics of several novel microsatellite DNA loci as well as cross-amplified loci for marbled salamanders and mole salamanders that may be used for future studies. In the second chapter, I report estimates of sire number for 13 marbled salamander clutches based on microsatellite data from 32 hatchlings per clutch. Females mated with as many as three different males as indicated by conservative techniques. Less than half of females mated with multiple males. Based on comparative analyses, I recommend the parental reconstruction approach with the computer program GERUD for assessing multiple paternity. The third chapter describes an experiment designed to study sexual selection. As expected, in breeding mesocosms, the potential for sexual selection was much higher for males than for females. Size was unrelated to variance in male reproductive fitness. Only opportunity for selection and Morisita’s index conformed to theoretical expectations of the relationship between operational sex ratio and the potential for sexual selection among males. Because opportunity for selection has intuitive links to formal sexual selection theory, I recommend its continued use. In the fourth chapter, I compared polyandrous and monandrous females to explore the potential fitness consequences of multimale mating. No fitness measure at the egg or hatchling stage (clutch size, hatching success, hatchling size, etc.) differed between the two types of clutches. Size of metamorphs was not different, but polyandrous clutches had significantly higher survival to metamorphosis. In the fifth chapter, I analyzed effects of increased polyandry and male availability on genetic diversity, effective population size (Ne), and fitness of experimental populations. Although no analyses were significant, some effects were moderate to high in size. Ne was higher when estimated from hatchlings than with metamorphs.

Nos estudos sobre a teoria da Seleção Sexual, as libélulas têm sido amplamente estudadas devido à grande variedade de padrões comportamentais, de coloração e táticas reprodutivas. Como forma de demonstrar táticas reprodutivas adotadas por duas espécies de libélulas, esta dissertação teve como objetivos principais: i) investigar o papel de traços secundários como a coloração corporal na competição intra-sexual de uma espécie territorial e ii) analisar se os traços corporais como tamanho e morfologia das asas predizem a tática de acasalamento adotada por machos de uma espécie nãoterritorial. Sugere-se que a coloração corporal pode predizer o resultado de lutas e também se correlacionar positivamente com a condição física dos machos territoriais de Tigriagrion aurantinigrum. Ademais, traços corporais como o tamanho e a morfologia das asas influenciam na tática reprodutiva utilizada por machos não-territoriais de Epipleoneura williamsoni. Portanto, com os resultados obtidos, conclui-se que a variação nos sinais visuais exerce um papel essencial na comunicação animal e na resolução de conflitos, indicando ainda que pode haver uma sinalização da condição física dos machos. Além disso, os resultados mostraram evidências em como diferentes táticas reprodutivas se relacionam com traços corporais como agilidade e tamanho corporal, os quais podem influenciar no sucesso reprodutivo dos indivíduos. / In studies concerning Sexual Selection theory, dragonflies and damselflies have been well studied due to their wide range of behavioral, color and reproductive tactics patterns. To demonstrate reproductive tactics adopted by two damselfly species, this study aimed to: i) investigate the role of secondary traits such as body coloration in intrasexual competition of a territorial species and ii) analyze if body traits such as size and wing morphology predicts the adopted tactic by non-territorial males. It is suggested that body coloration can predict the fight outcome and also positively correlates with males physical condition in territorial males of Tigriagrion aurantinigrum and body traits such as body size and wing morphology influence the reproductive tactic adopted by non-territorial males of Epipleoneura williamsoni. Therefore, with these results, it is concluded that the visual signalling variation plays an important role on the animal comunication and conflict resolution, which also may indicate that there is a signalling on the males physical condition. Furthermore, the results showed evidence in how different reproductive tactics are related to body traits such as agility and size, which can influence on individuals reproductive success.

A musicalidade, concebida como o conjunto da capacidade cognitiva subjacente à dança e à comunicação sonora por meio de melodias harmonizadas e ritmadas, satisfaz vários critérios que caracterizam as adaptações biológicas. A música é muito antiga, universal e um importante aspecto em todas as culturas e épocas conhecidas. Ela provoca emoções e reações estéticas fortes, se desenvolve segundo um roteiro ontogenético padrão, envolve uma capacidade neurocognitiva especializada em receber, processar e produzir música, traz benefícios à saúde e apresenta fatores hereditários nas diferenças individuais, consome muita energia e tempo, e tem análogos na sinalização acústica de outras espécies sugerindo homologia e convergência adaptativa. Existem duas principais teorias acerca do valor adaptativo para a musicalidade: coesão grupal e seleção sexual. Elas não são excludentes ou incompatíveis e apresentam muitas sobreposições. Ambas buscam, em diferentes contextos sociais, as pressões seletivas envolvidas na valorização ancestral dos responsáveis pela produção musical e sua apreciação. Entretanto, elas diferem quanto ao grau de diferenças sexuais previsto: a coesão de grupo prevê poucas diferenças sexuais, mas para a seleção sexual as mulheres seriam mais voltadas para apreciação musical, enquanto os homens seriam mais voltados para a exibição musical via instrumento musical. O maior desafio para o enfoque adaptacionista da musicalidade é a ampliação do teste experimental de hipóteses. O objetivo geral desta tese é investigar empiricamente, por meio de diferentes propostas metodológicas, aspectos divergentes e convergentes das influências da seleção sexual e da coesão de grupo na evolução da musicalidade humana integrada às outras artes. Esta tese consiste de quatro estudos que abrangem experimentos naturais e verdadeiros controlados, acessando de forma direta e 13 através de auto-relato tanto a apreciação quanto a produção musical, usando metodologias que requerem a colaboração dos participantes (questionários e gravações do canto), e outras com medidas discretas (como estatísticas oficiais de vestibulares desde 1980), amostrando ampla variedade de cursos de graduação e pós em diferentes regiões do Brasil (São Paulo e Natal) e no exterior (Holanda e Canadá). O conjunto dos resultados revela interculturalmente e temporalmente a existência de diferenças sexuais mais quanto às motivações e disposições para e musicalidade e outras artes do que para capacidades específicas. Os homens são mais voltados para a produção musical instrumental, enquanto as mulheres são mais voltadas para a produção musical cantada, dança, apreciação musical e outras manifestações artísticas. As estratégias sexuais se relacionaram à exibição musical cantada e tocada para os homens, e à importância e apreciação musical para as mulheres. Imaginar-se em um contexto de coesão grupal influencia mais o julgamento dos músicos a partir da música para os homens e num contexto amoroso mais para as mulheres. Ambas, seleção sexual e a coesão de grupo se mostraram inter-relacionadas de novas maneiras. Uma visão ampla e integradora sobre a evolução da musicalidade e das outras artes emergiu do conjunto de resultados e suas implicações / The human musicality, considered as a set of underlying cognitive abilities to dance and sound communication through harmonized rhythmic melodies, meets several criteria which characterize biological adaptations. Music is very old, and an important aspect in all cultures and known past historical periods. It provokes strong emotions and aesthetic responses, it unfolds according to a standard developmental schedule, involves a specialized neurocognitive ability in its perception, processing and production, it gives health and psychological benefits, and there is some hereditary factors on individual differences. It is also very energy-intensive and time consuming, and there are some similarities to the acoustic signalling of other species, suggesting homology and adaptive convergence. There are two main theories about the adaptive values for human musicality, group cohesion and sexual selection. They are not mutually exclusive or incompatible, and exhibit much overlap. Both seek, in different social contexts, the selective pressures involved in the ancestral advantages for music production and appreciation. However, they differ in predictions related to sexual differences: the group cohesion predicts few sex differences, whereas sexual selection predicts that women would be more dedicated to music appreciation, while men would be more focused on displaying via musical instrument. The biggest challenge to the adaptationist approach to musicality is the expansion of the empirical testing of hypotheses. The aim of this thesis is to empirically investigate, using different methodological approaches, divergent and convergent aspects of the influence of sexual selection and group cohesion in the evolution of human musicality, integrating it with the other arts. This thesis consists of four studies covering natural experiments and real controlled ones, using direct and self-report assessments of both the 15 musical appreciation and production. We used methods that require the collaboration of the participants (questionnaires and recordings of the singing), and methods using discrete measurements (such as official statistics of vestibular since 1980). And we sampled a wide variety of undergraduate and graduate courses in different regions of Brazil (Sao Paulo and Natal) and abroad (the Netherlands and Canada). The overall results revealed cross-culturally and temporally the existence of sex differences, more on the motivational side to music and other arts than on specific skills. Men are more focused on instrumental music production, while women are more devoted to singing, dance, music appreciation and all other art forms. Sexual strategies were related to displays such as singing and playing for men, and the importance of music and music appreciation for women. Imagining oneself in a context of group cohesion influenced the person perception of the musicians by their music for men, and romantic context influenced womens judgment about the musicians. Both sexual selection and group cohesion proved to be interrelated in new ways. A broad and inclusive way of viewing the evolution of human musicality and other arts has emerged from the confluences of results as their implications

O comportamento animal associado a características morfológicas fornece evidências para um melhor entendimento de como o comportamento sexual tem evoluído, e como os organismos podem maximizar seu sucesso reprodutivo. Fatores como tamanho, reservas de energia e outros caracteres sexuais como a coloração são essenciais para o melhor desempenho em relação a outros indivíduos da mesma espécie. Estes podem transmitir informação da qualidade do macho para outros machos co-específicos como também para às fêmeas. Esta qualidade, guarda relação com a condição física (reservas de energia) que possuem, e é necessária para ter sucesso na reprodução. Sendo a reprodução uma das mais custosas em términos energéticos em comparação a outras atividades, é de se esperar que os animais invistam a maioria das reservas no comportamento reprodutivo, o qual influencia no tipo de estratégia que eles adotam e à duração em tempo das interações relacionadas a reprodução, entre outras. Portanto indivíduos com características melhor desenvolvidas ou com boa condição física, terão uma vantagem na reprodução que os outros indivíduos da comunidade. Zenithoptera lanei é uma espécie neotropical presente no Brasil, da qual se tem poucos estudos sobre sua ecologia comportamental, sendo uns dos mais importante o realizado por Guillermo-Ferreira no 2015, para descrever as estruturas que conformam esta pruinosidade e sua função na comunicação intraespecífica. Neste estudo, descrevemos o comportamento sexual de Z. lanei (Libellulidae), com a hipótese que nesta espécie apresentam machos territoriais, e que a coloração de suas asas, o tamanho corporal e a reserva de energia (gordura) devem desempenham um papel importante na condição territorial. Assim, os machos com maior quantidade de energia e maior tamanho deveriam ganhar disputas, defender territórios e, portanto, manter a condição territorial. Além, avaliamos também se essa condição de territorialidade poderia influenciar o tempo de duração das cópulas e a oviposição pelas fêmeas. Os resultados mostraram que machos são territoriais, e esta territorialidade está relacionada com a condição física e tamanho. Sendo que, machos com maior tamanho corporal e maior quantidade de reservas de energia ganharam mais disputas e mantiveram um território. Apesar dos machos serem territoriais, não houve diferença entre a duração do tempo das interações reprodutivas para machos vencedores em comparação aos machos perdedores, indicando que o tempo de duração das interações reprodutivas não são influenciadas pela condição de territorialidade do macho. / Animal behavior associated with morphological characteristics supplies evidence for a better understanding of how sexual behavior has evolved, and how organisms can maximize their reproductive success. Factors such as size, fat reserves and other sexual characters such as coloration are essential to individual better performance in relation to conspecifics. These factors? Can bring information of the male quality to other conspecifics and females. This quality keeps relation with the physical condition (energy reserves) that they have which is required to succeed in breeding, as reproduction is one of the most expensive activity in energy cost in relation to other activities. The reproductive behavior is related to the individual fat reserves that influences, among other factors, in the condition that they adopt and to the duration in time of the related interactions to reproduction. Therefore, individuals with more developed characteristics or with better physical conditions will have an advantage in the reproduction comparing with other individuals of the community. The dragonfly Zenithoptera lanei is a Neotropical species present in Brazil, only studied so far by Guillermo-Ferreira in 2015, when structures that conform this pruinosity and his function in the intraspecific communication were described. In this study, describe the sexual behavior of Z. lanei (Libellulidae). Was hypothesized that in this species males present territorial behavior, and that the coloration of wings, body size and the energy reserves (fat) may play an important role in territorial condition and reproductive success. Thus, males with higher quantity of energy and larger size should win more disputes, defend territories and, therefore, maintain the territorial condition. In addition, was also assessed whether this condition of territoriality may influence the duration of the copulation and oviposition by females. The results showed that males are territorial, and its territoriality keeps relation with size and the physical condition. In other words, males with larger body and higher energy reserves have won more disputes and maintained a territory. Although males were territorial, there was no difference between the duration of reproductive interactions, winning males and losers, thus indicating that the reproductive interactions are not influenced by the condition of territoriality of the male.