Machos dos opiliões goniosomatíneos Serracutisoma spelaeum e Serracutisoma guaricana, cujas fêmeas copulam com mais de um parceiro em um único período reprodutivo, apresentam uma grande variedade morfológica, especialmente relacionada a caracteres sexuais secundários. Considerando-se que machos menores frequentemente perdem disputas por fêmeas, esta tese objetivou verificar possíveis estratégias reprodutivas alternativas, resultantes de seleção sexual pré e pós-copulatória, adotadas por machos de pequeno porte dessas espécies assim como o papel da fêmea nesses mecanismos. Este trabalho foi, então, dividido em três capítulos, cada um com objetivos específicos. O primeiro deles refere-se à organização do trato reprodutor feminino e caracterização das espermatecas, órgãos de armazenamento de espermatozóides. Imagens de microscopia de luz e de microscopia eletrônica de varredura associadas às obtidas sob estereomicroscópio revelaram a existência de quatro espermatecas inseridas na musculatura da porção distal do ovipositor. Cada uma delas é constituída por quatro sáculos individuais de fundo cego e se comunica com a luz do ovipositor através de um único canal. A complexidade das espermatecas indica que a fêmea pode ser capaz de armazenar separadamente os espermatozóides dos diferentes machos com os quais vier a copular, enquanto a musculatura ao redor dessas estruturas sugere que ela possa determinar a paternidade de sua progênie através de contrações diferenciais. O capítulo 2 abrange observações comportamentais e características morfológicas e morfométricas do trato reprodutor masculino, objetivando identificar possíveis estratégias alternativas utilizadas por machos de pequeno porte na obtenção de sucesso reprodutivo. Para tal, foram efetuados acompanhamento do comportamento sexual e estudos morfométricos de genitália e da gônada. Machos de pequeno porte parecem adotar a estratégia de machos-satélites, copulando com as fêmeas quando machosguardiões estão com a atenção desviada. A ausência de diferenças estatísticas significativas na largura da placa ventral sugere que o pênis de machos grandes e de machos pequenos se ajustam à genitália feminina da mesma maneira e, portanto, sejam vii avaliados pelas fêmeas da mesma forma. Já a semelhança no comprimento da genitália e o menor tamanho corpóreo dos machos pequenos indicam que, durante a cópula, eles poderiam alcançar regiões mais profundas da espermateca, removendo ou deslocando os espermatozóides dos outros machos e, consequentemente, diminuindo o risco de competição espermática. A análise ultraestrutural dos espermatozóides (compostos por núcleo, citoplasma e acrossomo, além de diversas projeções na superfície) mostrou que, provavelmente, todos os machos possuam espermatozóides viáveis, visto que espermatozóides não-férteis, em geral, não possuem acrossomo. As similaridades entre machos de grande e de pequeno porte tanto na morfologia dos gametas como em seu comprimento indicam que tais características possam ter sido objeto de seleção sexual pós-copulatória. O terceiro capítulo propõe uma hipótese para a formação das projeções encontradas nos espermatozóides das duas espécies e que lhes confere uma morfologia peculiar. Para isso foi utilizada a associação de três técnicas de microscopia: microscopia eletrônica de transmissão, de varredura e confocal de varredura a laser. Os resultados obtidos evidenciam que essas estruturas são formadas ao longo do processo de espermatogênese. Uma rede de proteínas situada logo abaixo da membrana plasmática exerceria uma pressão sobre o citoplasma, que extravasaria pelos espaços existentes nessa espécie de malha. Dessa forma, as projeções seriam constituídas de citoplasma envolto por membrana plasmática. Em conclusão, os resultados obtidos na presente tese sugerem que a competição espermática e a escolha críptica da fêmea, componentes da seleção sexual póscopulatória, são pressões seletivas atuantes nessas duas espécies de opilião. / Males of the goniosomatine harvestmen Serracutisoma spelaeum and Serracutisoma guaricana, which females may copulate with more than one partner during the same reproductive season, show a large morphological variation, especially considering secondary sexual features. Since smaller males frequently lose fights against larger males for females, the present thesis aimed at verifying the occurrence of alternative reproductive strategies among these smaller males as a result of pre- and postcopulatory sexual selection, as well as the role of the female in these mechanisms. This study is composed of three chapters, each one with specific objectives, as described as follows. The first chapter describes the general organization of the female reproductive system and the spermathecae, structures for the storage of sperm. Ligth and scanning electronic microscopy images revealed the presence of four spermathecae inserted in the musculature of the distal portion of the ovipositor. Each spermatheca is composed of four individual dead-end sacs and is connected to the ovipositor lumen through a single channel. This complex spermathecae structure indicates that the female is able to store sperm from different males with which she copulates in different places, and that the musculature that involves these structures may be responsible for differential contractions which would result in different paternity for the females descendants. The second chapter includes behavioral observations and morphological and morphometric analysis of the male reproductive system (genitalic and gonadal features), aiming at identifying possible alternative reproductive strategies used by small males to achieve reproductive success. Small males seem to adopt a satellite-male strategy, copulating with females when larger guardian-males are not paying attention. The absence of significant statistic differences in the width of its ventral plate suggests that the penis of both large and small males may adjust to the female genitalia in the same way and, therefore, will be similarly evaluated by the female during copulation. In turn, the smaller length associated to the same sized penis of smaller males in comparison to the larger ones may indicate that they may reach deeper regions of the female genitalia during copulation, possibly removing or displacing the sperm of other males and, in consequence, reducing the risk of sperm competition. The ultrastructure analysis of the spermatozoa (which are composed of a nucleus, cytoplasm and an acrosome, in addition to several surface projections) showed that probably males of different sizes all have viable sperm, since generally non-fertile spermatozoa lack an acrosome. Similarities in the morphology and size of the gametes of both small and large males may indicate that these features have been subjected to postcopulatory sexual selection. The third chapter suggests a new hypothesis for the development of the projections found in the surface of the spermatozoa of the two species here studied. For this study, three microscope techniques were used: transmission electronic microscopy, scanning electronic microscopy, and confocal laser scanning microscopy. The results show that these projections are formed during the spermatogenesis. A net of proteins situated just below the plasmatic membrane restrains the cytoplasm, which flows through the spaces formed in the net, forming the projections, which are externally limited by plasmatic membrane. In conclusion, the results obtained in the present study suggest that sperm competition and female cryptic choice, which are components of the postcopulatory sexual selection process, are selection pressures working on the species studied herein.

A seleção sexual atua de forma significativa na evolução de características reprodutivas. Os machos apresentam diversas estratégias para garantir a fertilização da fêmea, a qual, por sua vez, possui papel crucial em processos pré- e pós-copulatórios. Nesse contexto, cefalópodes apresentam aspectos reprodutivos peculiares, apresentando transferência de espermatozoides via espermatóforos e, em alguns casos, armazenamento desses gametas em órgãos especializados (i.e., receptáculos seminais). Entretanto, pouco se sabe sobre a morfologia, funcionamento e mecanismos de captação, armazenamento e liberação dos espermatozoides pelos receptáculos seminais. Neste contexto, a presente dissertação teve como objetivo investigar a estrutura e função do receptáculo seminal de Doryteuthis plei, espécie de lula adotada como modelo, como base para compreensão de mecanismos pós-copulatórios de seleção sexual em cefalópodes. Para atingir esse objetivo, a morfologia do receptáculo seminal foi analisada com base em microscopia integrativa (microscopia óptica com emprego de técnicas histoquímicas, microscopia eletrônica de varredura e de transmissão, microscopia confocal e microCT), visando a uma caracterização detalhada da estrutura do órgão. Além disso, a morfologia e histologia/histoquímica do receptáculo seminal foi analisada em três situações experimentais distintas: (1) antes de cópula recente, (2) após cópula recente (e antes da desova) e (3) após a desova, para investigar alterações morfológicas no órgão e no volume de espermatozoides armazenados, como base para compreensão dos mecanismos de captação, armazenamento e liberação de gametas masculinos pela fêmea. Os resultados revelaram enorme complexidade do receptáculo seminal com relação à diversidade de células secretoras e de fibras musculares associadas. Constatou-se que há alteração das células secretoras após a cópula recente e após a desova, com liberação do conteúdo de parte dessas células. Com base nos resultados obtidos, discute-se o papel dessas secreções na captação, armazenamento e liberação de espermatozoides. Além disso, a estrutura dos sistemas nervoso e muscular associados ao receptáculo seminal sugere que a fêmea tenha controle sobre deformações precisas do órgão relacionadas à captação e liberação de espermatozoides. Entretanto, outros mecanismos seriam igualmente possíveis, como atração química, natação ativa dos espermatozoides e ação ciliar do órgão. Alguns receptáculos seminais foram encontrados com espermatângios (i.e., espermatóforos evertidos) bloqueando total ou parcialmente sua abertura. Devido à frequência, posição e morfologia dos espermâtangios dentro do receptáculo seminal, propõe-se a hipótese de que essas estruturas poderiam atuar também como plugues copulatórios. Esses plugues seriam mais eficientes nas primeiras 24 horas, sua eficiência sendo gradualmente reduzida com o tempo após a cópula, devido ao esvaziamento do conteúdo espermático e consequente redução de sua turgidez. Embora plugues copulatórios sejam conhecidos em inúmeras espécies de animais, este é o primeiro registro para cefalópodes, sendo, portanto, marco importante nos estudos de seleção sexual para o grupo. Cefalópodes são considerados modelos interessantes para o estudo de seleção sexual e os resultados desta dissertação contribuem para compreensão dos complexos mecanismos pós-copulatórios em lulas, como escolha críptica da fêmea e competição espermática / Sexual selection exerts a significant pressure on the evolution of reproductive attributes. Males show a diverse array of strategies to gain advantage in mating and fertilization success, but females also play a crucial role in pre- and post-copulatory sexual selection processes. Within this context, cephalopod mollusks show peculiar reproductive strategies, including sperm transfer via spermatophores, and the presence of female sperm-storage organs (seminal receptacles). However, the knowledge of the functioning of the cephalopod seminal receptacles is scarce, the mechanisms involved with sperm uptake, storage and release being unknown. To shed light on post-copulatory mechanisms in cephalopods, the present dissertation aimed at investigating the structure and function of the seminal receptacle of the squid Doryteuthis plei. To achieve this goal, the morphology of the seminal receptacle was thoroughly analyzed applying integrative microscopy (light microscopy including histochemical techniques, scanning & transmission electron microscopy, confocal microscpy and microCT). Moreover, to investigate morphological and sperm volume changes associated with possible mechanisms of sperm uptake, storage and release by the organ, the morphology and histology/histochemistry of the seminal receptacle was also analyzed under three distinct experimental manipulations: (1) before recent mating (2) after recent mating (and before egg release) and (3) after egg release. The results show a complex and striking diversity of secretory cells and associated muscle fibers in the seminal receptacle. There were changes in the composition and predominance of secretory cells between major reproductive events, suggesting a secretory activity associated with mating and spawning. The possible roles of these secretions in sperm uptake, storage and release are discussed in light of our data. Moreover, the structure of the nervous and muscular systems associated with the receptacle suggests that females have control over precise deformations of the organ, possibly related to sperm uptake and release. However, other mechanisms would be possible, such as chemical attraction, sperm active swimming, and ciliary action. Seminal receptacles were sometimes found with spermatangia (i.e., everted spermatophores) blocking totally or partially their openings. Given their frequency, position, and morphology, we hypothesize spermatangia might function as copulatory plugs that physically obstruct the female storage organ. Plug efficiency should be high within the first 24 hours after mating, gradually decreasing its efficiency with time, when spermatangia lose their turgidity by releasing part of their sperm content. Although copulatory plugs have been reported for numerous taxa, this is the first record for cephalopods, and as such this finding has an impact for sexual selection studies based on these mollusks. Cephalopods are considered interesting models to investigate sexual selection, and this study has cast some light on the understanding of complex post-copulatory mechanisms in squids, such as cryptic female choice and sperm competition

<p>Menstruationscykelns inverkan på kvinnors preferenser för mäns ansikten</p><p>Sammanfattning</p><p>Detta är en systematisk replikation av Penton-Voaks och Perrets studie (1999) då en preferens hos kvinnor för maskuliniserade ansiktsdrag under hög befruktningsrisk i menstruationscykeln hittades. Dessa drag tros vara en ärlig signal för goda gener och immunokompetens hos män. Oklarhet råder huruvida detta gäller för olika populationer. 36 svenska universitetsstuderande kvinnor fick därför välja ut de mest fysiskt attraktiva ansiktena, utifrån maskuliniserade och feminiserade bildserier, vid hög respektive låg befruktningsrisk. Ingen signifikant skillnad hittades mellan de olika faserna. Resultaten indikerar att fynden för menstruella preferensskiften inte är robusta över olika populationer och att det eventuellt är flera evolutionära mekanismer som opererar samtidigt. Alternativt kan kulturella faktorer spela en större roll än vad som tidigare förutsatts.</p> / <p>Women’s Preferences for Male Facial Masculinity Across the Menstrual Cycle</p><p>Abstract</p><p>This is a systematic replication of the Penton-Voak and Perret study (1999) where a preference for masculinized faces was found at high conception risk in the menstrual cycle. These traits are believed to be honest signals of good genes and immunocompetence. It is uncertain if these findings are robust across different populations. 36 Swedish college students were asked to pick out the most “physically attractive” male faces from masculinized and feminized stimuli at high and low risk of conception. No significant differences were found between the phases. The results indicate that the findings for a menstrual preference shift are not consistent with the original study . Perhaps several evolutionary mechanisms are operating at the same time, and cultural factors might have a greater influence than previously supposed.</p>

<p>This thesis integrates the fields of sexual selection, parental investment and sex role theory by investigating mutual mate choice and mate competition in the sex role reversed deep snouted pipefish <i>Syngnathus typhle</i> (Pisces: Syngnathidae) through a series of laboratory experiments. In<i> S. typhle</i>, the female transfers her eggs to the male's brood pouch where they are nourished and oxygenated for about a month, when the male gives birth to the independent fry.</p><p>Mate choice was found to be adaptive. Both sexes benefited from mating with preferred partners in terms of increased offspring viability and got larger, or faster growing, offspring when mating with large fish. Females were also shown to prefer males with thicker brood pouches. Thus, females, the more competitive sex, had multiple preferences. Both male and female choice behaviour was found to be flexible and influenced by available information on partner quality. In addition, males, but not females, copied the mate choice of consexuals. </p><p>Both sexes were found to take their own quality in relation to surrounding competitors into account when deciding whether to display to potential partners. Male-male competition was found to influence both the mate choice of males and, potentially, overrule the mate choice of females. Males did not compete as intensely as females, nor did they use their sexual ornament in this context as females do. Rather, the ornament was used in interactions with females, and males that displayed more received more eggs.</p><p>The findings in this thesis emphasise the importance of not viewing mate choice and competition as opposite behaviours, but rather to apply a dynamic approach in mate choice studies, integrating choice and competition in both sex</p>

Whether microevolutionary processes can explain macroevolutionary patterns has long been a matter of contentious debate. The debate has persisted largely because of the challenging task of connecting microevolutionary theory, which examines population-level phenomena on the generation scale, to data collected across larger spatial and temporal scales. My dissertation research broadly examines phenotypic evolution across multiple scales by connecting microevolutionary theory to macroevolutionary phenomena such as speciation and large-scale phenotypic change. In particular, I focus on the so-called "paradox of stasis"; which wrestles with the apparent conflict between frequently-observed cases of rapid evolution on short timescales and the frequent appearance of stasis in the fossil record. I attempt to link micro and macroevolution by using the theoretical framework of evolutionary quantitative genetics for modeling the effects of drift and selection. My four dissertation chapters examine four different systems (1) connecting quantitative genetic models of sexual selection to speciation (2) connecting microevolutionary and macroevolutionary body size data across scales of time (3) using phylogenetic comparative methods and quantitative genetic models to examine the evolution of a classic example of stasis, mammalian body temperature and (4) finally, using multi-locus phylogeography to understand the evolutionary processes that contribute to the diversification of a widespread snake across broad spatial scales. In chapter 2, I demonstrate that genetic drift combined with sexual selection can promotes speciation and diversification of male ornaments. Furthermore, I demonstrate that drift promotes the evolution of elaborate ornaments even when preferences are costly. In chapter 3, I combine data from microevolutionary field studies, the fossil record, and phylogenetic comparative data into a single analytical framework to resolve apparent conflicts between micro and macroevolutionary patterns. To do so, I compiled and analyzed the largest database of phenotypic divergence data in existence. I demonstrate that patterns of stasis persist until a million-year threshold, after which divergence begins to accumulate in a time-dependent manner. This pattern is best fit with a hierarchical model that describes evolution as occurring in bursts on the million-year timescale, but that allows for rapid, but bounded, evolution on short timescales. In chapter 4, I demonstrate that mammalian body temperature -- which has been previously presented as a classic example of stasis -- does in fact evolve extensively across the mammalian radiation (albeit slowly). Furthermore, I show that mammalian body temperature evolves in response to changing environmental conditions. Finally, I evaluate the role that genetic constraints play in the apparent slowness of body temperature evolution. In chapter 5, I examine a well-studied empirical system of garter snakes in which a strong signature of stabilizing selection has been found for phenotypic traits. Using multiple mitochondrial and nuclear loci, I show that introgression is rampant between species, and dynamic patterns of range expansion, contraction, and introgression among clades have led to a complex pattern of genetic variation. This structure of genetic variation underscores the need to examine range-wide processes for generating phenotypic divergence across clades. Overall, these chapters suggest that apparent disconnects between microevolutionary processes and macroevolutionary patterns could be explained by the scaling of population-level theory over large spatial and temporal scales. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from Oct. 25, 2012 - Oct. 25, 2013

Thesis (M.A.)--State University of New York at New Paltz, 2007. / Also issued in electronic version. Includes bibliographical references (leaves 29-31). Online version available via the SUNY New Paltz Sojourner Truth Library : http://hdl.handle.net/1951/39633

Understanding the processes that govern mating behaviors is a fundamental goal of evolutionary biology and behavioral ecology. Population-level patterns of mate acquisition and offspring production, otherwise known as the genetic mating system, play a central role in the sexual selection on morphological and behavioral traits and may facilitate speciation. The central hypothesis of this research is that variation in environmental conditions, such as temperature, turbidity, and habitat, and demographic influences such as population density, sex ratios and temporal availability of mates, may limit mating and reproductive success in a predictive manner. Therefore the goal of this dissertation is to examine the contributions of geographic and temporal variation on the plasticity of the genetic mating system in two species of pipefish. The first study examined whether meaningful variation in the genetic mating system exists between two natural populations of the dusky pipefish, Syngnathus floridae. Results of this investigation provide evidence that the genetic mating system differs among different geographic locations. The second study considered the relative contributions of environmental conditions and population demographics on differences in the genetic mating system of dusky pipefish from five natural populations. The results of this investigation show strong trends for demographic and environmental factors to strongly influence the genetic mating system between populations. The third study considered how variation in the number of available mates predicts the outcome of sexual selection during the course of a breeding season in the broad-nosed pipefish, Sygnathus typhle. The results of this study indicate a strong influence of the operational sex ratio on the genetic mating system. In addition to these studies, a study was conducted to investigate whether phylogeographic relationships may be responsible for geographic variation in the genetic mating system of the dusky pipefish of pipefish. Mitochondrial DNA analysis does not substantiate subspecies designations for this species and microsatellite analysis show a clear pattern of isolation by distance. Taken together, these studies significantly enhance the understanding of how mating systems are organized over broad environmental gradients and temporal/spatial scales and to the evolution of sexual selection on the whole.

This thesis integrates the fields of sexual selection, parental investment and sex role theory by investigating mutual mate choice and mate competition in the sex role reversed deep snouted pipefish Syngnathus typhle (Pisces: Syngnathidae) through a series of laboratory experiments. In S. typhle, the female transfers her eggs to the male's brood pouch where they are nourished and oxygenated for about a month, when the male gives birth to the independent fry. Mate choice was found to be adaptive. Both sexes benefited from mating with preferred partners in terms of increased offspring viability and got larger, or faster growing, offspring when mating with large fish. Females were also shown to prefer males with thicker brood pouches. Thus, females, the more competitive sex, had multiple preferences. Both male and female choice behaviour was found to be flexible and influenced by available information on partner quality. In addition, males, but not females, copied the mate choice of consexuals. Both sexes were found to take their own quality in relation to surrounding competitors into account when deciding whether to display to potential partners. Male-male competition was found to influence both the mate choice of males and, potentially, overrule the mate choice of females. Males did not compete as intensely as females, nor did they use their sexual ornament in this context as females do. Rather, the ornament was used in interactions with females, and males that displayed more received more eggs. The findings in this thesis emphasise the importance of not viewing mate choice and competition as opposite behaviours, but rather to apply a dynamic approach in mate choice studies, integrating choice and competition in both sex

Menstruationscykelns inverkan på kvinnors preferenser för mäns ansikten Sammanfattning Detta är en systematisk replikation av Penton-Voaks och Perrets studie (1999) då en preferens hos kvinnor för maskuliniserade ansiktsdrag under hög befruktningsrisk i menstruationscykeln hittades. Dessa drag tros vara en ärlig signal för goda gener och immunokompetens hos män. Oklarhet råder huruvida detta gäller för olika populationer. 36 svenska universitetsstuderande kvinnor fick därför välja ut de mest fysiskt attraktiva ansiktena, utifrån maskuliniserade och feminiserade bildserier, vid hög respektive låg befruktningsrisk. Ingen signifikant skillnad hittades mellan de olika faserna. Resultaten indikerar att fynden för menstruella preferensskiften inte är robusta över olika populationer och att det eventuellt är flera evolutionära mekanismer som opererar samtidigt. Alternativt kan kulturella faktorer spela en större roll än vad som tidigare förutsatts. / Women’s Preferences for Male Facial Masculinity Across the Menstrual Cycle Abstract This is a systematic replication of the Penton-Voak and Perret study (1999) where a preference for masculinized faces was found at high conception risk in the menstrual cycle. These traits are believed to be honest signals of good genes and immunocompetence. It is uncertain if these findings are robust across different populations. 36 Swedish college students were asked to pick out the most “physically attractive” male faces from masculinized and feminized stimuli at high and low risk of conception. No significant differences were found between the phases. The results indicate that the findings for a menstrual preference shift are not consistent with the original study . Perhaps several evolutionary mechanisms are operating at the same time, and cultural factors might have a greater influence than previously supposed.

At the centre of the vertebrate immune system is a group of proteins called MHC (major histocompatibility complex) molecules. These function in self – non self recognition and activation of the immune defence against intruding parasites and pathogens. In this thesis I have investigated individual variation in MHC class II genes and antibody producing ability in relation to ecology and behaviour in the great snipe (Gallinago media), a lekking bird, breeding in northern Europe. There was much variation in the MHC genes of the great snipe and the sequence data show that balancing selection has been acting on these genes. I found genetic differentiation in the MHC between two separate geographic regions of the great snipe distribution. Furthermore, this structure was more pronounced than that previously found in neutral genetic markers, suggesting that different selection pressures (possibly resulting from variation in parasitic fauna) are acting in these different regions. The birds produced specific antibodies following injection with two novel antigens. Males that were chosen as mates, had higher antibody titers than their neighbouring males, suggesting that this ability may be important in female mate choice. Such choice could give the offspring an enhanced immune system or could favour females directly by avoidance of sexually transmitted diseases. Females choosing to mate with a male having a different set of MHC genes than their own could give the offspring immune system the ability to react to a wide range of parasites. No such mate choice could, however, be found in the great snipe. Instead, females preferred males with certain MHC alleles, irrespective of their own MHC type. If those alleles confer resistance to parasites currently prevailing in the population, such resistance would be inherited by the offspring, thereby enhancing their fitness.