Buzz-pollination or pollination by vibration occurs in several families of angiosperms including some important commercial crops such as potatoes and tomatoes. Buzz-pollinated flowers release pollen via small pores or slits on the anther’s tip that require the use of vibrations by specialized pollinators, usually bees, to remove the pollen. Some buzz-pollinated species have elaborate floral morphologies including dimorphic anthers within the same flower (heteranthery), and mirror-image flowers (enantiostyly) where the style is reciprocally deflected to either the left or right side of the floral axis. The complex floral morphology and buzz-pollination syndrome seen in these species require a close physical interaction between the sexual organs of the flowers and the bodies of insect visitors. Despite the broad taxonomic distribution of buzz-pollination in angiosperms (more than 60 families are buzz-pollinated) relatively few studies have described the pollination ecology of these species under natural conditions. The main goal of the present work was to characterize the pollination biology, mating patterns and antagonistic interactions (e.g. pollen theft) in natural populations of a buzz-pollinated species. For this purpose, I studied Solanum rostratum (Solanaceae), a buzz-pollinated, self-compatible, annual weed with complex floral morphology (both enantiostylous and heterantherous flowers). This species usually grows in disturbed areas in its native range (Mexico) and has become invasive around the world. My research was divided into three components. First, I characterized the pollination and reproductive biology of natural populations in Mexico. I performed floral manipulations in six natural populations of S. rostratum to estimate fruit and seed set. In three of these populations, I carried out 115 hours of pollinator observations and quantified the incidence of pollinators versus pollen thieves. I also measured the efficiency of a subset of floral visitors in triggering fruit set after single visits. Second, I investigated whether morphological correspondence between the size of the pollinator’s body and floral morphology influences pollen transfer. In experimental arrays, I exposed flowers of S. rostratum that varied in the distance between their sexual organs, to bumblebees (Bombus terrestris) of different sizes, and recorded pollen deposition and fruit and seed production. Finally, I determined the mating system (i.e. the proportion of self- and cross-fertilized offspring) of natural populations in Mexico and of introduced populations in the United States of America, using newly developed microsatellite markers. My results show that S. rostratum is visited by a wide range of bees of different sizes (0.9–9.8 mm in thorax diameter), but that only a small subset of these visitors act as pollinators. Most visitors act as pollen thieves, consuming pollen while effecting little or no pollination. I also found that correspondence between a pollinator’s size and the separation of the S. rostratum sexual organs determines pollen deposition and fruit production; pollen deposition decreased when bees were small relative to the distance between the sexual organs visited the flowers. My genetic analyses show that natural populations of S. rostratum maintain a relatively high outcrossing rate (tm = 0.75 ± 0.03) across the native and introduced range. Furthermore, genetic diversity is reduced in invasive populations, but this is not accompanied by changes in mating system. My work shows that the morphological fit between the pollinator and the flowers is important in determining the dynamics of pollen transfer and fruit production in this buzz-pollinated plant. Distinguishing between pollinators and pollen thieves in buzz-pollinated plants is essential for understanding the evolution of buzz-pollination, as pollen theft could be a major selective force for these species.

Understanding how floral traits covary with one another and with mating patterns is an important step in understanding how and why mating systems evolve. I examined the evolution of floral and mating system variation in Camissoniopsis cheiranthifolia (Onagraceae), a species that exhibits divergence in key floral traits expected to be associated with variation in the relative importance of outcrossing vs. self-fertilization. I combined geographic surveys of floral variation with genetic estimates of the proportion of seeds outcrossed (t) and confirmed that t covaried with corolla width and herkogamy in a predictable way both within and among populations. I then performed geographic surveys, manipulative experiments and genetic analyses to evaluate the potential role that; inbreeding depression (ID), interactions between flowers, pollinators and florivores, and reproductive assurance (RA) may have played in shaping and/or maintaining the geographic pattern of mating system variation in this species. The main selective factor maintaining outcrossing in large flowered (LF) populations appears to be ID, which was much stronger in LF compared to small flowered (SF) populations. These results are also consistent with purging of ID in SF populations. Increased selfing appeared to alleviate pollen limitation (PL) because it was associated with higher and less variable fruit set and reduced florivory by a microlepidopteran. However, evidence that florivores preferentially attacked larger flowers was equivocal. LF experienced stronger PL than SF populations suggesting that one condition for the evolution of selfing via RA is met in outcrossing populations. Floral emasculation experiments revealed that the timing of selfing also covaried with flower size among and within populations. SF self-pollinate before flowers open but LF do not, suggesting that selfing evolved in response to chronic outcross PL. Negative side effects of emasculation were detected which prevented a clear interpretation of the RA value of selfing. Given that much of what is known about RA comes from emasculation experiments, my results suggest that the assumptions of this approach, which are rarely verified, require more serious consideration. Taken together my results suggest that C. cheiranthifolia has evolved multiple stable mixed mating systems perhaps in response to selection for RA. / Thesis (Ph.D, Biology) -- Queen's University, 2012-12-30 14:13:46.366

Gaining a good understanding of marine turtle mating systems is fundamental for their effective conservation, yet there are distinct gaps in our knowledge of their breeding ecology and life history, owing largely to the difficulty in observing these highly mobile animals at sea. Whilst multiple mating by females, or polyandry, has been documented in all marine turtle species, the fitness consequences of this behaviour have not been fully investigated. Furthermore, male mating patterns, operational sex ratios and the number of males contributing to breeding populations are poorly understood, impeding accurate assessments of population viability. In this thesis, I use molecular-based parentage analysis to study, in detail, the genetic mating system of two green turtle (Chelonia mydas) populations. In the focal population in northern Cyprus, I show that, despite exhibiting a strongly female-biased hatchling sex ratio and contrary to our expectations, there are at least 1.3 breeding males to every nesting female. I go on to assess the breeding frequency of male turtles in the population and determine that males do not breed annually at this site, demonstrating that the observed relatively equal sex ratio of breeders is not the result of a few males mating every year, but that the number of breeding males in the population is greater than expected. I show that 24% of nesting females in the population produce clutches with multiple paternity, but do not detect any fitness benefits to polyandrous females, and discuss the potential role of sexual conflict in influencing female mating decisions. Finally, I reveal a high frequency of multiple paternity in green turtle clutches on Ascension Island, one of the largest green turtle rookeries in the world, and discuss possible causes of variation in the level of polyandry among marine turtle populations. The results presented here shed new light on aspects of marine turtle mating systems that are challenging to study, and illustrate the value of molecular data, not only in describing mating patterns, but in elucidating aspects of life history and behaviour that would otherwise be very difficult to ascertain.

This thesis investigates the pattern of parental educational homogamy and its implications for parenting practices and children’s early development in contemporary Britain. At the heart of the thesis lies an interest in the mechanisms behind the intergenerational transmission of educational success and, more specifically, the consequences for children of new patterns of parental resemblance in education. The thesis is composed of three empirical chapters, each of which is concerned with a different outcome: 1) trends in educational attainment and educational assortative mating amongst parental couples; 2) parents’ childrearing values and stimulation-oriented interactions with children; and 3) children’s early cognitive and behavioural skills. The first chapter combines data from four birth cohort studies from 1958, 1970, 1990 and 2000-01 while the second and third chapters rely exclusively on the latter study. The empirical analyses use Log-linear and Diagonal Reference models. With regard to trends in educational assortative mating, the thesis finds that the strength of homogamy increased between 1958 and 1970 to decrease thereafter and remain stable, at its lowest level, throughout the 1990s. Moreover, amongst recent cohorts of parental couples the percentage of unions where mothers are more educated than their male partners equalled that of unions exhibiting the opposite pattern. The findings concerning the dynamics of parenting in heterogamous couples suggest a pattern of female dominance in the attitudinal domain as fathers align with the views that can be expected on the basis of the mother’s level of education rather than their own; however, no significant adjustments between partners are observed in parenting behaviours. Lastly, the thesis finds a positive gradient in the association between parental education and children’s early cognitive and socio-emotional development but little or no support for the hypotheses of differential effects for sons and daughters or gender biases in parental preferences for children. That is, no significant interactions are observed between the gender of children and the impact of parents’ absolute and relative levels of education. Taken together, the findings of the thesis qualify concerns about the increase of educational assortative mating in industrialised societies and its potential consequences for the intergenerational reproduction of inequalities in education.

La phénologie du débourrement est un caractère adaptatif majeur, sensible aux variations de température. Prédire l'évolution des forêts naturelles tempérées sous l'influence de changements environnementaux nécessite de pouvoir expliquer l'origine des patrons de différentiation clinaux observés pour ce caractère à l'échelle de paysages. Il a été démontré expérimentalement que le débourrement végétatif se produisait en même temps que la floraison. Cela suggère que les croisements se font préférentiellement entre arbres présentant des phénologies du débourrement similaires ; c'est ce que l'on appelle l'homogamie. Alors que la plupart des interprétations de clines de différenciation génétique soulignent l'influence de la sélection divergente, les spécificités de la phénologie du débourrement et ses conséquences sur le système de reproduction sont rarement considérées. A travers une approche par modélisation nous montrons ici dans un premier temps que la seule interaction entre homogamie et flux de pollen peut générer une différentiation génétique clinale à l'échelle d'un paysage sans aucune pression de sélection. Dans un tel contexte théorique, le filtragedes flux de pollen réalisé par l'homogamie en présence d'un gradient environnemental différencie progressivement et durablement les populations. Dans un second temps, nous montrons que l'homogamie amplifie la réponse adaptative des populations à la sélection co-gradient alors qu'il la contraint dans le cas de sélection contre-gradient. Nous montrons par ailleurs que l'homogamie peut induire une différentiation clinale en cas de sélection uniforme. / Timing of bud burst (TBB) is a key adaptive trait affected by temperature variations. Predicting the evolution of natural forests undergoing environmental variations requires to understand the evolutionary dynamics that have resulted in the strong patterns of differentiation characterized for this trait. It has been shown experimentally that the TBB was strongly correlated with the timing off lowering. This suggests that trees having similar TBB tend to mate preferentially, making assortative mating at TBB the default reproduction regime within tree species. Clinal patterns of genetic differentiation have been mostly interpreted as resulting from divergent selection, however, few studies have considered the peculiar features of timing of bud burst. Through a modelling approach based on quantitative genetics models, we first demonstrate here that the sole interaction between assortative mating at TBB and pollen flow can induce a clinal differentiation among populations without any selection pressure. In a such theoretical context, assortative mating filters pollen flow in presence of environmental gradients and progressively shifts the genetic values of populations. Then, we demonstrate that assortative mating amplifies the adaptive response of populations to co-gradient selection, and constrains it in the case of countergradient selection. Finally, we show that assortative mating differentiates populations even in the case of uniform selection.

Worldwide, pharmaceutical compounds continue to increase in our aquatic environment. The predominant route into nature is through wastewater treatment plants since the elimination of residual pharmaceuticals is still not mainstream in WWTPs. Fluoxetine is an antidepressant which is commonly prescribed to treat human depression. Wastewater residual fluoxetine is typically found in waters around the world, and can thus affect exposed organisms, such as fish and invertebrates. However, how fluoxetine may affect mating behaviour in exposed organisms remains poorly understood, and particularly so in invertebrates. This is hampering our understanding of the consequences of our medicine leaking into nature because mating behaviour often affects fitness, and invertebrates are key organisms in food chains. Therefore, I here experimentally investigated long-term effects of environmental relevant concentration of fluoxetine (20 ng L-1) on mating behaviours of male and female freshwater isopod Asellus aquaticus. I demonstrate that fluoxetine reduced male mating attempts with receptive females. Further, there was a tendency for fluoxetine exposure to increase latency to form pre-copula. There was no effect of fluoxetine exposure on male latency to encounter females or female responses toward males. These results indicate that fluoxetine also can affect isopods by reducing mating behaviour. In the long-term, if reproduction is delayed or reduced, it may cause a reduction in populations and thus, alter the whole ecosystem.

O bioma Mata Atlântica tem sofrido com a fragmentação florestal e como forma de reestabelecer ambientes florestais são realizados plantios de restauração. Porém, por muito tempo houve preocupação somente com a composição florística das áreas e a diversidade genética foi negligenciada. Além disso, muitas áreas são implantadas a partir de sementes coletadas em áreas florestais geralmente pouco conservadas, pequenas e isoladas, o que pode comprometer a qualidade genética das mudas, produzindo indivíduos menos adaptados em decorrência da depressão endogâmica. Assim este trabalho teve como objetivo principal analisar o aspecto genético em áreas de restauração na região do Pontal do Paranapanema e área natural de referência, o Parque Estadual Morro do Diabo (PEMD), utilizando o jatobá (Hymenaea courbaril L.) como espécie modelo. No capítulo 1 com o objetivo de verificar a diversidade genética de H. courbaril em áreas de restauração florestal, foram selecionadas duas áreas de plantio com espécies nativas. Nestas áreas e no PEMD foram coletadas amostras foliares de indivíduos adultos que foram genotipadas para oito locos microssatélites. No PEMD ainda foram coletados frutos em 12 matrizes para caracterização do sistema reprodutivo. As três áreas estudadas apresentaram diversidade genética e níveis de endogamia similares. Nas três áreas de estudo foi identificada baixa estruturação genética espacial. Houve predomínio de fecundação cruzada para a produção de frutos na área natural, porém a taxa de cruzamentos entre indivíduos aparentados foi até dez vezes maior que a observada em outras populações da espécie. No capítulo 2 com o objetivo de verificar se há depressão endogâmica em progênies provenientes do PEMD foram selecionadas 320 sementes de 12 matrizes. Estas e seus frutos foram medidos. As plântulas a que deram origem também foram mensuradas, mensalmente, durante 15 meses. Todos os indivíduos foram genotipadas para oito locos microssatélites. A coancestria, foi estimada e os indivíduos separados em: não aparentados (tu), aparentados (tr) e autofecundação (s). Foi verificada diferença entre as métricas das plantas de acordo com o nível de coancestria entre indivíduos. Também foram estimados os valores de depressão endogâmica (ID). A quantidade de indivíduos irmãos de autofecundação foi muito pequena, sendo a maioria proveniente de cruzamento entre indivíduos não aparentados. A depressão endogâmica por autofecundação foi mais evidente no peso e tamanho dos frutos, e amena ou inexistente para os demais caracteres. Isto provavelmente por estas sementes terem sido coletadas em um fragmento grande e bem conservado e que ainda não sofre as consequências da depressão endogâmica. Assim, nosso trabalho mostrou que áreas de restauração florestal que seguiram as recomendações genéticas de implantação, apresentam diversidade genética suficiente para H. courbaril, podendo estas áreas serem fonte de coleta de sementes no futuro. E que os indivíduos provenientes de sementes do PEMD não apresentaram efeito de depressão endogâmica até 15 meses de desenvolvimento em viveiro. / The Brazilian Atlantic Forest was severely deforested and restoration initiatives are necessary to reestablish environments. However, for a long time there is only concern over floristic composition and the genetic diversity has been neglected. In addition, several restoration areas are planted from seeds collected in forest areas that are generally poorly preserved, small and isolated, which may compromise the genetic quality of the seedlings, producing less adapted individuals due to inbreeding depression. The aim of this work was to analyze the genetic aspects of Hymenaea courbaril L. in restoration areas in Pontal do Paranapanema region, and a natural reference forest, the Morro do Diabo State Park (PEMD), where seeds were also collected. In Chapter 1, to verify the genetic diversity of H. courbaril in areas of forest restoration, using eight microsatellites, two restoration areas were selected. In these areas and in the PEMD, leaf samples from adult individuals were collected. In the PEMD, fruits were collected in 12 seed trees for mating system characterization. The three areas presented similar genetic diversity and levels of inbreeding. Low spatial genetic structure was identified in the three studied areas. In the natural forest, fruits were mainly produced through outcrossings, but the rate of mating among relatives was up to ten times higher than the observed in other H. courbaril populations. In Chapter 2, to verify the inbreeding depression in the PEMD were selected 320 seeds from eight seed trees. The seeeds and their fruits were measured. The seedlings were also measured monthly, during 15 months. All seedlings were genotyped with eight microsatellite loci. From the pairwise coancestry the seedlings were separated into three categories: outcrossing among unrelated individuals (tu), outcrossing among related individuals (tr), and selfing (s). We verified differences among groups in the metrics of seedlings according to the level of coancestry among individuals. The values of inbreeding depression (ID) were also estimated. The number of selfed seedlings were very small, and the majority were from outcrossing among unrelated individuals. Inbreeding depression by selfing was more evident in weight and size fruit, and was insignificant or non-existent for other characters. This is probably because these seeds were collected in a large and preserved forest fragment, that does not suffer the consequences of inbreeding depression yet. Thus, our work showed that forest restoration areas that followed the genetic recommendations present enough genetic diversity for H. courbaril, and these areas may be a source of seeds for collection in the future. Besides that, seedlings from seed trees in PEMD did not present inbreeding depression effect up to 15 months of nursery development.

In some species with uniparental care, when the parental individual deserts the offspring or dies, its mate may adopt the parental responsibilities, a behaviour known as flexible compensation of uniparental care. However, for most of the species in which this behavioural response has been reported in the literature, there was no thorough investigation of its effects upon offspring fitness to support it. In the Neotropical harvestman Serracutisoma proximum, a species with female uniparental care, harem-owning males stand on unattended clutches when the egg-tending females desert or die. Here, we investigate if this species constitutes an actual example of flexible compensation of uniparental care by evaluating the effects of ecological (namely climatic conditions and mate availability) and life-history factors (namely male attractiveness, clutch size and filial cannibalism) on males\' behaviour and, ultimately, on offspring survival. We expect unfavourable climatic conditions, as well as low mate availability and male attractiveness, to negatively affect the exhibition of compensatory behaviours, but a positive effect of clutch size. Moreover, we expect an increase in the extent of filial cannibalism to be a strategy that alleviates the costs of compensation. However, males\' behaviour towards unattended offspring has no effect on offspring survival, and other results were inconsistent with our predictions except for climatic conditions affecting the extent of both the presumed behaviour of standing on unattended clutches and filial cannibalism. Our results, therefore, do not support the existence of flexible compensation of uniparental care in S. proximum. Rather than a parental activity, we argue that males’ behaviour corresponds to a mating tactic that increases fertilization and mating success with the returning egg-tending females or newcomer mates foraging on the unattended offspring. This study demonstrates that for presumed cases of flexible compensation of uniparental care it is necessary to evaluate the effects on offspring fitness since not always an apparent parental behaviour is what it seems to be / Em algumas espécies com cuidado uniparental, quando o individuo parental deserta a prole ou morre, seu parceiro pode adotar as responsabilidades parentais, um comportamento conhecido como compensação flexível do cuidado uniparental. No entanto, para a maioria das espécies em que esta resposta comportamental tem sido relatada na literatura, não houve uma investigação completa de seus efeitos sobre a aptidão da prole para apoiá-lo. No opilião Neotropical Serracutisoma proximum, uma espécie com cuidado uniparental da fêmea, os machos donos de harem ficam sobre desovas desatendidas quando as fêmeas que deveriam cuidar dos ovos desertam ou morrem. Aqui, investigamos se esta espécie constitui um exemplo real de compensação flexível do cuidado uniparental, avaliando os efeitos de fatores ecológicos (condições climáticas e disponibilidade de parceiras) e de história de vida (atratividade do macho, tamanho da desova e canibalismo filial) sobre o comportamento dos machos e, em última instância, sobre a sobrevivência da prole. Esperamos que condições climáticas desfavoráveis, assim como baixa disponibilidade de parceiras e atratividade do macho, afetem negativamente a exibição de comportamentos compensatórios, mas que o tamanho da desova tenha um efeito positivo. Além disso, esperamos que um aumento na intensidade do canibalismo filial seja uma estratégia que alivie os custos da compensação. Entretanto, o comportamento dos machos em relação à prole desatendida não tem efeito sobre a sobrevivência da prole, e os outros resultados foram inconsistentes com nossas previsões, exceto pelas condições climáticas que afetam tanto a intensidade do comportamento dos machos sobre as desovas quanto o canibalismo filial. Nossos resultados, portanto, não apoiam a existência de compensação flexível do cuidado uniparental em S. proximum. Ao invés de uma atividade parental, argumentamos que o comportamento dos machos corresponde a uma tática de acasalamento que aumenta o sucesso de fertilização e de acasalamento com as fêmeas que retornam às suas desovas ou com novas fêmeas que se alimentam dos ovos desprotegidos. Este estudo demonstra que, para os casos em que se pressupõe compensação flexível de cuidado uniparental, é necessário avaliar os efeitos sobre a aptidão prole, uma vez que nem sempre um aparente comportamento parental é o que parece ser

O processo reprodutivo é de extrema importância para os organismos vivos, é através dele que os indivíduos transmitem as informações contidas em seus genes para as próximas gerações. Para que qualquer indivíduo seja bem-sucedido nesse processo, o primeiro desafio a ser superado é encontrar um parceiro sexual. Para cumprir essa tarefa, machos e fêmeas comunicam sua presença utilizando uma variedade de canais sensoriais. Nas abelhas sociais,o encontro entre machos e fêmeas é um processo complexo e resultado de um refinado sistema de comunicação, mediado principalmente por sinais químicos. Embora Meliponini seja o maior e mais diverso grupo de abelhas sociais, existem poucas informações sobre a comunicação sexual desses insetos. Um fenômeno comum nesse grupo de abelhas é a formação de grandes agregados de machos nas proximidades de colônias que possuem uma rainha virgem. No entanto, os sinais envolvidos na atração dos machos e na formação desses agregados são pouco conhecidos. Desse modo, este trabalho objetivou investigar os fatores envolvidos na comunicação sexual de Meliponini. Para explorar esse problema, nós realizamos uma revisão sobre a biologia reprodutiva dessas abelhas (cap. 1), testamos o papel das forrageiras na atração de machos (cap.2), identificamos os compostos presentes nas marcas depositadas por machos nas agregações (cap.3) e investigamos os fatores relacionados à escolha dos machos por uma determinada colônia (cap. 4). Os resultados obtidos apontam que as forrageiras têm um papel central na atração dos machos e que os machos depositam ativamente seus hidrocarbonetos cuticulares nos locais de agregação. Além disso, foi possível identificar que a atratividade de uma colônia está relacionada com a sua biomassa. Assim, esses resultados contribuem para ampliar nosso conhecimento sobre o processo reprodutivo em abelhas sem ferrão e mostram que a comunicação sexual desse grupo de insetos é um processo tão complexo quanto fascinante que envolve machos, rainhas e operárias / Reproduction is the utmost important process for living organisms since it is through this process that individuals can transmit their genetic information to the next generation. To be successful in this process, the first challenge individuals need to overcome is finding a sexual partner. To accomplish this task, males and females communicate their presence using several sensorial modalities. In highly eusocial bees, this complex process is the outcome of a precise chemical communication system. Stingless bees (Meliponini) represents the most species-rich group of eusocial bees and although a lot of information related to the group can be found in the literature, very little is known about their mating communication. A common phenomenon in this group of social bees is the formation of large male aggregations in front of nests during reproductive events. However, the factors involved in the formation of such male aggregation are poorly understood. Therefore, the aim of this study was to investigate the mating communication of stingless bees. To explore this problem, we reviewed the mating biology of the bees (chapter 1), tested the role of foragers in the attraction of males (chapter 2), identified the compounds that drones deposit at the aggregation site (chapter 3) and investigated the factors related to the differential attraction of males to colonies (chapter 4). Our results suggest that foragers have a central role in the long-range attraction of males and that males actively deposit their cuticular hydrocarbons at the aggregation site. Furthermore, we observed that the number of attracted males increased with the weight of colonies, showing that the attractiveness of colonies is related to their biomass. Thus, these results contribute to improve our knowledge about the reproductive process of stingless bees and show that the sexual communication of these bees is as complex as fascinating and involves males, queens and workers

This PhD thesis addresses several aspects of the biology and ecology of the squid Doryteuthis plei in the coast of São Paulo, SE Brazil, at both the population and individual levels. On the population structure of the exploited stock, it includes the patterns of reproductive activity, size-at-maturity, and biometrics of reproductive organs associated with squid size, as well as feeding habits and ontogenetic, sexual, and spatial-temporal shifts. Generalized Additive Models for Location, Scale, and Shape (GAMLSS) were used to identify such population patterns and spatial and temporal factors based on the particular small-scale fishery that targets the species around the São Sebastião Island. At the individual level, the study focused on behavioural traits in two periods of the life-cycle: (1) the reproductive phase, where the body patterns were described, generating a comprehensive ethogram for the species, and (2) the paralarval phase, where the development of swimming and predatory behaviours was detailed. Size-at-maturity was found to be 151-175 mm of mantle length (ML) for females, and 187-190 mm ML for males, that also showed the co-occurrence of two distinct maturation groups (Chapter 1). A significant peak of females gonad weight occurs in February and March especially in the island\'s South and Southeastern areas, and of males in March. An ethogram analysis showed 19 chromatic, 5 locomotor, and 12 postural components and behavioural sequences for the species, including agonistic, courtship, and mating behaviour (Chapter 2). Light chromatic components (clear and iridophore splotches) showed a longer duration than dark chromatic components, especially those associated with calm behaviour, more frequent in females. Males appeared more dedicated to disputes over resources and used fast miscellaneous visual signalling. In respect to feeding habits (Chapter 3), prey composition differed among sexes, size, maturity, and spatio-temporal pattern. Females do not stop feeding during sexual maturation and the amount of food increases with size. Cephalopods were significant preys for mature females, as well as fish and crustaceans to the largest females, while pelagic polychaetes were dominant prey for largest males. Observations and filming of D. plei paralarvae (Chapter 4) show a complex predatory behaviour on live preys, with different hunting types differing in speed and position. Aggressive intra-specific behaviour was found in the absence of prey when paralarvae show both a pursuit strategy and a rapid backward escape after attack. These findings contribute to better understand the population biology and behavior of the species and also in the future definition and guidance of fisheries management plans. / A presente tese aborda diferentes aspectos da biologia e ecologia da lula Doryteuthis plei na costa de São Paulo, SE do Brasil, tanto em nível individual quanto populacional. Com relação à estrutura populacional do estoque explorado, foram analisados padrões da atividade reprodutiva, tamanho de primeira maturação, morfometria dos órgãos reprodutivos associados às fases de desenvolvimento e também hábitos alimentares e mudanças ontogenéticas, sexuais e espaço-temporais. Modelos aditivos generalizados para localização, escala e forma (Generalized Additive Models for Location, Scale, and Shape - GAMLSS) foram utilizados com intuito de identificar padrões populacionais, espaciais e temporais baseados em desembarques da pesca de pequena escala em torno da Ilha de São Sebastiao. Em nível individual, o estudo abordou padrões comportamentais em 2 diferentes períodos do ciclo de vida: (1) fase de reprodução, onde padrões corporais foram descritos, tendo como resultado um abrangente etograma (2) fase paralarval, onde o desenvolvimento de comportamento natatório e predatório foram detalhados. O tamanho de primeira maturação foi estimado entre 151 e 175 mm de comprimento do manto (ML) para as fêmeas e entre 187 e 190 mm ML para os machos, também foi identificada a co-ocorrência de 2 grupos de maturação para os machos. (Capitulo 1). Um pico significativo com relação ao peso das gônadas foi identificado entre os meses de Fevereiro e Março para as fêmeas e em Março para os machos, especialmente nas áreas Sul e Sudeste da ilha. Uma análise dos comportamentos reprodutivos e dos padrões corporais, resultando em um amplo etograma, revelou 19 componentes cromáticos, 5 locomotores e 12 posturais, como também, sequências comportamentais para a espécie, incluindo comportamentos agonístico, de corte e acasalamento (Capitulo 2). Componentes cromáticos claros (manchas claras e irridóforos) apresentaram maior duração do que os componentes cromáticos escuros, particularmente aqueles relacionados ao comportamento calmo, mais frequente nas fêmeas. Machos aparentemente foram mais propensos a disputas por recursos usando sinalizações visuais rápidas e variadas. Em relação aos hábitos alimentares (Capítulo 3), a composição de presas diferiu entre sexos, tamanhos, maturidade e padrões espaço-temporais. As fêmeas não deixaram de se alimentar durante a maturação e foi observada uma relação positiva entre a quantidade de alimentos e o tamanho dos indivíduos. Pequenos cefalópodes, assim como peixes e crustáceos foram às presas mais significativas entre as fêmeas maduras, enquanto que para os machos foram os poliquetas. Através de observações e filmagens de paralarvas de D. plei (Capitulo 4), identificou-se um comportamento predatório complexo sobre presas vivas, com diferentes tipos de caça que diferem em velocidade e posição. Comportamentos agressivos entre indivíduos da mesma espécie (estratégias de ataque e fuga) foram identificados quando na ausência de presas. Estes achados contribuem para melhor compreender a biologia populacional, comportamento da espécie, e também na futura definição e orientação nos planos do manejo pesqueiro.