Um dos grandes problemas que afetam a produção in vitro de embriões é a variação entre touros em relação à fertilidade e o maior nascimento de embriões do sexo masculino. Muitos fatores podem alterar a razão de 1:1 entre os gêneros tanto na produção in vitro de embriões, como no método de Inseminação Artificial. No sentido de tentar alterar esta proporção sexual in vitro, estudamos em um primeiro momento, a variação entre touros no desenvolvimento de embriões machos e fêmeas, distribuídos nas fases de blastocisto jovem, blastocisto, blastocisto expandido e blastocisto eclodido, bem como, a proporção macho: fêmea em relação a fase do blastocisto. Para tanto, oócitos foram coletados de ovários oriundos de matadouro e maturados em meio de maturação em incubadora por 24h. Espermatozóides viáveis de 17 touros do Programa de Melhoramento Genético da Raça Nelore, obtidos por centrifugação em gradiente de Percoll, foram utilizados para Fecundação in vitro. Após 12h, os supostos zigotos foram cultivados em meio de cultivo e células do cumulus em incubadora. Ao sétimo dia após a fertilização in vitro foi feita a seleção dos blastocistos viáveis que foram sexados com a utilização de primers Y-específico bovino e autossômico bovino, com visualização dos fragmentos amplificados em gel de agarose. Posteriormente, para obtenção de maior conhecimento a respeito dos animais testados, coletamos dados de progênie a campo destes animais e verificamos a proporção sexual de seus filhos nascidos pelo método da inseminação artificial, monta natural e possíveis correlações com características quantitativas. Diferenças entre touros foram observadas em relação à proporção dos sexos para as fases de blastocisto inicial e blastocisto expandido. Não foi observado desvio da proporção sexual em relação ao touro utilizado na produção in vitro de embriões e progênie a campo. Nosso dados sugerem que é possível alterar a proporção macho:fêmea em sistemas de produção in vitro de embriões pela seleção do estágio do blastocisto para transferência, e ainda, sugerem que touros apresentam variação em relação ao desenvolvimento in vitro de embriões machos e fêmeas de acordo com o estágio do blastocisto. / Some of the main problems that affect the in vitro production of embryos is the variation among bulls in relation to fertility and the greater birth of male embryos. Many factors can change the ratio 1:1 between the genders, both in the in vitro production of embryos and in the method of artificial insemination. To try to change this sex ratio in vitro, we studied at first, the variation among bulls in the development of female and male embryos, the blastocyst-stage distributed in young blastocyst, blastocyst, expanded blastocyst and hatched blastocyst and the proportion male: female in relation to the blastocyst stage. For this, oocytes were collected from slaughterhouse ovaries and matured in maturation medium in an incubator for 24h. Viable sperm from 17 bulls belonging to the Breeding Program of Nellore, obtained by Percoll gradient centrifugation were used for in vitro fertilization. After 12 hours, the presumptive zygotes were cultured in culture medium and cumulus cells in an incubator. After 168 hours of in vitro fertilization the viable embryos in the blastocyst stage were classified. The determination of the sex of the blastocysts was performed by Polymerase Chain Reaction (PCR) using a Y-specific sequence and bovine autosomal sequence visualized in agarose gel. Data analysis was conducted using the Statistical Analysis System software. Later, to obtain more knowledge about the animals tested, data was collected from the field progeny of these animals and established the sex ratio of the offspring produced by the method of artificial insemination, natural mating and possible correlations with quantitative traits. Differences between bulls were observed relating to the proportion of genders at the initial stages of blastocyst and expanded blastocyst. No deviation was observed in the sex ratio in relation to the bull used for in vitro production of embryos and offspring in the field. Our data suggest that it is possible to change the male to female proportion in production systems of in vitro embryos through the selection of the blastocyst stage for transfer, and also suggest that bulls show variation in relation to the in vitro development of male and female embryos, depending on the blastocyst stage.

Submitted by Mariana Dornelles Vargas (marianadv) on 2015-03-17T19:15:15Z No. of bitstreams: 1 caracterizacao_demografica.pdf: 744506 bytes, checksum: 42673cbee87c239733082fd6c361167a (MD5) / Made available in DSpace on 2015-03-17T19:15:15Z (GMT). No. of bitstreams: 1 caracterizacao_demografica.pdf: 744506 bytes, checksum: 42673cbee87c239733082fd6c361167a (MD5) Previous issue date: 2010 / Nenhuma / No presente estudo são apresentados os primeiros parâmetros populacionais para a população de Phrynops hilarii do Lago dos Pedalinhos no Parque Farroupilha (30º02'13"S; 51º13'03"W), Porto Alegre, Brasil. Esta população foi analisada quanto a sua estrutura, abundância, razão sexual e existência de dimorfismo sexual em tamanho. As capturas dos espécimes foram realizadas semanalmente entre 8:30h e 15:00h, em dois dias consecutivos, entre maio e dezembro de 2009. Todos os indivíduos capturados foram pesados, sexados (sempre que possível) e marcados com um número individual de identificação. Em adição, em cada espécime capturado foram realizadas nove medidas lineares externas. Após o fim do procedimento, todos os indivíduos capturados foram liberados no mesmo local onde foram coletados. A abundância da população foi estimada através do método para populações abertas de Jolly-Seber e a razão sexual foi obtida através da divisão do número total de machos pelo total de fêmeas. A existência de dimorfismo sexual nas medidas externas foi testada pelo teste-t, apenas para os indivíduos sabidamente adultos e de sexo conhecido. Como resultados foram capturados 53 espécimes de P. hilarii durante o período de estudo, dos quais 16 eram machos, 25 eram fêmeas e 12 indivíduos tiveram o sexo não determinado. Além disso, 77% eram adultos e 22% subadultos. A abundância populacional de P. hilarii no Lago dos Pedalinhos foi estimada em 282,67 indivíduos e a razão sexual foi significativamente diferente de 1:1 e inclinada a favor das fêmeas, com a existência de um macho para cada 1,56 fêmeas. O resultado do teste-t indicou a existência de um acentuado dimorfismo sexual no tamanho, sendo as fêmeas, de uma maneira geral, maiores que os machos, à exceção das medidas da distância máxima da base da cauda ao orifício cloacal e da distância máxima da base à ponta da cauda. Nos quelônios o dimorfismo sexual no tamanho é comum e isto poderia ser um dos fatores que influenciam na maturação e no crescimento diferencial entre os sexos de uma mesma espécie. Acredita-se que a população de P. hilarii do Lago dos Pedalinhos é resultante, principalmente, de indivíduos descartados pela comunidade local, após terem sido mantidos em cativeiro (como animais de estimação) por algum período. Os dados obtidos no presente estudo demonstram que apesar das populações de quelônios de parques urbanos estarem vivendo em áreas altamente antropizadas, elas ainda seriam capazes de manter parâmetros populacionais semelhantes aos das populações naturais de vida livre, sugerindo que estes animais seriam extremamente resistentes às pressões antrópicas. A maior causa de mortalidade dos quelônios em parques urbanos é em decorrência de maus-tratos, atropelamentos, predação e ataque de animais domésticos, bem como por poluição e competição com espécies afins que ocupam o mesmo ambiente (Trachemys dorbigni e T. scripta elegans). Por fim, as populações de P. hilarii de parques urbanos também poderiam servir de modelo na compreensão dos reais efeitos da atividade humana sob quelônios de vida livre em outras áreas impactadas. / In this study is presented the first population parameters to the population of Phrynops hilarii from “Lago dos Pedalinhos” (30º02'13"S; 51º13'03"W), an urban lake from the city of Porto Alegre – Brazil. The population structure, size, abundance, and sex ratio as well sexual dimorphism in size were analyzed. The captures and data collection were conduced weekly, between May and December 2009. All the captured specimens were weighed, sexed (whenever possible) and marked with a number of identification. In order to evaluate the differences in size between sexes nine body measurements were taken from adult males and females. After completed the procedure, all individuals captured were released in the same place that they were caught. The population abundance was estimated by Jolly-Seber method for open populations and the sex ratio was calculated by the division between the total number of males and females. The sexual dimorphism in body measurements were tested between sexes using t-test, just for adult individuals with known sex. As a result, 53 specimens of P. hilarii were captured, which 77% were adults and 22% subadults. From this total, 16 were males, 25 females and 12 were of unknown sex. The population abundance of P. hilarii in the study area was estimated in 282.67 specimens. The sex ratio was statistically different from the expected ratio 1:1 and was biased in favor of females (1 male to 1.56 females). The t-test results revealed pronounced sexual dimorphism in body size, with females being larger than males, with the exception of the tail’s measurements (CCD1 and CCD2). In chelonians the sexual dimorphism in size is common and it may be one of the factors that influence the maturation and differential growth between the sexes. It is believed that studied population is formed, mainly, by animals released by the local co mmunity, after being kept in captivity, like pets. The observed results suggest that the ch elonian populations that live in urban parks are able to keep the regular population parameters similar to the wild populations of the species, even living in highly impacted areas. In addition, it indicates that this population is extremely resistant to anthropogenic pressure. The mortality of chelonians in urban parks generally is due to direct human actions, such as maltreatment, running over, predation and by the attack of domestic animals, as well pollution and competition with related species that live in the same area (Trachemys dorbigni and T. scripta elegans). Finally, the study of chelonians from urban parks could be used as a model for under standing the real effects of the human activity on the wild populations of freshwater turtles

Orientador: Luiz Claudio Nogueira Mendes / Coorientador: Sergio Moraes Aoki / Banca: Flavia Lombardi Lopes / Banca:Gisele Zoccal Mingotti / Banca:Maria denise Lopes / Banca: Eduardo Harry Birgel Junior / Resumo: Novas metodologias para a sexagem de sêmen são buscadas devido à citometria de fluxo apresentar limitações e desvantagens e os aptâmeros surgem como potenciais candidatos para a identificação de espermatozoides conforme a presença do cromossomo X ou Y. Os objetivos foram avaliar o uso de três aptâmeros desenvolvidos para se ligarem especificamente ao espermatozoide Y na separação magnética por sexo de espermatozoides de touro, e desenvolver uma técnica de qPCR que permita realizar facilmente o diagnóstico da proporção sexual em amostras de sêmen. Protocolos de separação por magnetismo utilizando aptâmeros biotinilados foram utilizados em sêmen comercial, e duas frações de espermatozoides foram obtidas para cada aptâmero testado (livre e retida). A proporção relativa de espermatozoides Y foi analisada em reações de qPCR desenvolvidas para este objetivo. A curva padrão utilizada na qPCR foi eficiente para a quantificação da proporção sexual relativa em amostras de sêmen convencional e sexado. Diferença significativa da proporção relativa de Y foi encontrada na fração de espermatozoides livres do aptâmero C12 em relação ao controle (47,7% vs. 51,3%, respectivamente; P = 0,009); as demais separações não apresentaram diferença significativa. Os aptâmeros selecionados não produziram o efeito desejado de separação do sêmen conforme a presença do cromossomo X ou Y, nestas condições utilizadas, mas a diminuição da proporção relativa de Y em uma das frações não retidas indica ser possí... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sex preselection of livestock offspring represents a big potential for genetic improvement. There are a search for new methods to sex-sort bull semen in order to avoid the limitations of flow cytometry/cell sorting technique. Aptamers emerge as potential candidates for sperm identification relative the presence of chromosome X or Y. In this work, the objectives were 1, to evaluate three aptamers developed to specifically binding to the Y-bearing sperm in magnetic separation by sex of bovine sperm and 2, to develop a SYBR Green Real-Time PCR method to determinate sex ratio in bovine semen in semen samples. Separation protocols by magnetism using biotinylated aptamers were used in commercial semen, and two fractions of sperm were obtained for each tested aptamer (free and trapped). The relative ratio of Y-bearing spermatozoa was analyzed in qPCR reactions developed for this purpose. The standard curve for qPCR was efficiently designed to quantify the sex relative ratio of sorted and unsorted semen samples. Significant difference in the relative proportion of Y-bearing sperm was found in the fraction of free sperm samples from aptamer C12 compared to the control samples (47.7% vs. 51.3%, respectively; P = 0.009); other separations showed no significant difference. Selected aptamers did not produce the wanted effect of sperm separation by the presence of chromosome X or Y, in these conditions used, but decreased relative proportion of Y-bearing sperm in one of the free fractions ... (Complete abstract click electronic access below) / Doutor

The traditional view of a lifelong monogamy between a king and a queen has recently been challenged in termites. In several species, multiple parthenogenetically-produced secondary queens replace the primary queen and mate with the primary king; this strategy is referred to as “Asexual Queen Succession” (AQS). The aim of my thesis was to investigate the modalities of reproduction and the ecology of neotropical soil-feeding termites from the Termitinae, with a focus on the inquiline termite Cavitermes tuberosus in the Termes group.In the first axis, we investigated the modalities of reproduction of C. tuberosus. (i) AQS is the main reproductive strategy of this species. (ii) The evolution of AQS requires the propensity of parthenogens to develop into neotenic queens. In C. tuberosus, secondary queens develop from a developmental stage of “aspirants” which participate to the social tasks usually undertaken by workers, as long as the primary queen is alive. (iii) In AQS species, a female-biased sex ratio is expected in the dispersing reproductives. In C. tuberosus, sex ratio varies among years and according to the type of reproductives, and the population sex ratio is balanced. These results raise hints on queen-king conflict over the sex ratio.In the second axis, we described the ecology and symbioses of C. tuberosus. (iv) Wolbachia, an endosymbiotic bacterium mainly known for manipulating the reproduction of arthropods in order to enhance its own transmission, infects all individuals in societies. This bacterium, particularly abundant in a gut-associated bacteriome, may play a role in the nutrition of C. tuberosus; both partners would have evolved a mutualistic symbiosis. (v) Inquiline termites live in a nest built by other termite species and do not forage outside. Physico-chemical measures and microbiota sequencing revealed that C. tuberosus is a generalist nest-feeder.Finally, we expanded our study of the breeding systems in the phylogenetic proximity of C. tuberosus. (vi) We described Palmitermes impostor, a new genus and species as a sister-group to the genus Cavitermes. (vii) AQS is the main reproductive strategy in P. impostor, and queens of Spinitermes trispinosus and Inquilinitermes inquilinus are able to reproduce parthenogenetically. Therefore, it appears likely that the conditional use of sexual and asexual reproductions is a preadaptation common to the whole Termes group, and that it evolved into a stable element of their breeding system at least in some species.Overall, our results open new perspectives in the understanding of reproductive strategies in termites and their relationships with their bacterial symbionts. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

O Laboratório de Poluição Atmosférica Experimental da Faculdade de Medicina da Universidade de São Paulo desenvolve várias linhas de pesquisa sobre os efeitos da poluição nos organismos vivos. O objetivo deste trabalho foi estudar as alterações no sistema reprodutor de camundongos balb-c machos expostos a água de manancial localizado próximo a depósito de resíduos químicos. Oitenta camundongos balb-c foram divididos em quatro grupos: Grupo A (controle) recebeu água mineral, grupo B recebeu água de nascente na região do depósito, grupo C recebeu água de cidade abastecida por água originada na região do depósito e grupo D recebeu água de rio que passa ao lado do depósito. A exposição foi do desmame até a idade adulta. Ao atingir a idade reprodutiva eles foram acasalados e posteriormente sacrificados. Os parâmetros avaliados foram: peso das gônadas, espermograma, taxa de gravidez, proporção de machos na prole e contagem de células de Sertoli. A análise da água do grupo A e C não mostrou presença de poluentes, a do grupo B mostrou presença de cádmio nas concentrações de 3,58 ± 0,50 microgramas/L e de 2,92 ± 0,10 microgramas/L, a do grupo D mostrou a presença de hidrocarbonetos aromáticos policíclicos, de chumbo nas concentrações de 113 ± 11 microgramas/L e de 221 ± 16 microgramas/L, cádmio nas concentrações de 11,33 ± 0,50 microgramas/L, 12,6 ± 1,2 microgramas/L e 3,78 ± 0,35 microgramas/L e de mercúrio nas concentrações de 4,58 ± 0,92 microgramas/L e 5,3 ± 1,1 microgramas/L. Foram utilizados os testes de Levene e Kolmogorov-Smirnov para se verificar a homogeneidade das variâncias e a aderência a curva normal, respectivamente. Para as variáveis que apresentaram esses dois princípios satisfeitos foram utilizados testes paramétricos (ANOVA- analise de variância), caso contrario foram utilizados testes não paramétricos (Teste de Kruskall-Wallis). Quando diferenças foram observadas foi utilizado o teste de comparações múltiplas de Tukey (KLEIBAUM). Os resultados mostraram que houve redução significativa da proporção de machos na prole dos animais do grupo B e uma redução marginalmente significante nos animais do grupo D. Os outros parâmetros avaliados não mostraram diferenças entre os grupos. A alteração verificada na proporção de machos do grupo B não pode ser explicada pela presença de cádmio na água, pois o grupo D foi exposto a doses muito maiores e não apresentou a mesma alteração. No presente trabalho não identificamos diferenças que permitam afirmar que a exposição à água da região do depósito de lixo químico cause alterações no sistema reprodutivo de camundongos / The Atmospheric Pollution Laboratory of The Sao Paulo University Medical College develops research on the effects of environmental pollution in health. This study investigated the effects on the reproductive system of balb-c mice exposed to water from a river near a deactivated waste depositary. Eighty male mice were separated in four groups: Group A (mineral water); Group B (water from the water treatment station); Group C (water from Cubatao city); Group D (water from the waste depositary region). They were exposed to water since they were weaned until they reached sexual maturity. They were coupled with females in reproductive age and after this mating time they were sacrificed. The evaluated parameters had been testicle weight, sperm analysis, pregnancy rate, sex ratio of the offspring and Sertoli cell count. The analysis of the water did not show presence of pollutants in the group a and group c water. Group b showed low levels of cadmium, 3,58 ± 0,50 g/L and 2,92 ± 0,10g/L. Group d showed the presence of PAHs and high levels of lead (113 ± 11 g/L and 221 ± 16 g/L), cadmiun (11,33 ± 0,50 g/L and 12,6 ± 1,2 g/L) and mercury (4,58 ± 0,92 g/L and 5,3 ± 1,1 g/L . The tests of Levene and Kolmogorov-Smirnov had been used to verify the homogeneity of the variances and the tack to the normal curve, respectively. The parametric tests used ANOVA and the non parametric tests used Kruskall-Wallis test and the test of multiple comparisons of Tukey (Kleibaun). Results: There were no differences between groups in testicle weight, sperm analysis, pregnancy rate and Sertoli cell count. There was a significant reduction in sex-ratio of the offspring in group b. This alteration cannot be explained by the cadmium levels in group b water. In the present work we cannot associate the exposition to water from the waste depositary and reproductive alterations

O Laboratório de Poluição Atmosférica Experimental da Faculdade de Medicina da Universidade de São Paulo desenvolve várias linhas de pesquisa sobre os efeitos da poluição nos organismos vivos. O objetivo deste trabalho foi estudar as alterações no sistema reprodutor de camundongos balb-c machos expostos a água de manancial localizado próximo a depósito de resíduos químicos. Oitenta camundongos balb-c foram divididos em quatro grupos: Grupo A (controle) recebeu água mineral, grupo B recebeu água de nascente na região do depósito, grupo C recebeu água de cidade abastecida por água originada na região do depósito e grupo D recebeu água de rio que passa ao lado do depósito. A exposição foi do desmame até a idade adulta. Ao atingir a idade reprodutiva eles foram acasalados e posteriormente sacrificados. Os parâmetros avaliados foram: peso das gônadas, espermograma, taxa de gravidez, proporção de machos na prole e contagem de células de Sertoli. A análise da água do grupo A e C não mostrou presença de poluentes, a do grupo B mostrou presença de cádmio nas concentrações de 3,58 ± 0,50 microgramas/L e de 2,92 ± 0,10 microgramas/L, a do grupo D mostrou a presença de hidrocarbonetos aromáticos policíclicos, de chumbo nas concentrações de 113 ± 11 microgramas/L e de 221 ± 16 microgramas/L, cádmio nas concentrações de 11,33 ± 0,50 microgramas/L, 12,6 ± 1,2 microgramas/L e 3,78 ± 0,35 microgramas/L e de mercúrio nas concentrações de 4,58 ± 0,92 microgramas/L e 5,3 ± 1,1 microgramas/L. Foram utilizados os testes de Levene e Kolmogorov-Smirnov para se verificar a homogeneidade das variâncias e a aderência a curva normal, respectivamente. Para as variáveis que apresentaram esses dois princípios satisfeitos foram utilizados testes paramétricos (ANOVA- analise de variância), caso contrario foram utilizados testes não paramétricos (Teste de Kruskall-Wallis). Quando diferenças foram observadas foi utilizado o teste de comparações múltiplas de Tukey (KLEIBAUM). Os resultados mostraram que houve redução significativa da proporção de machos na prole dos animais do grupo B e uma redução marginalmente significante nos animais do grupo D. Os outros parâmetros avaliados não mostraram diferenças entre os grupos. A alteração verificada na proporção de machos do grupo B não pode ser explicada pela presença de cádmio na água, pois o grupo D foi exposto a doses muito maiores e não apresentou a mesma alteração. No presente trabalho não identificamos diferenças que permitam afirmar que a exposição à água da região do depósito de lixo químico cause alterações no sistema reprodutivo de camundongos / The Atmospheric Pollution Laboratory of The Sao Paulo University Medical College develops research on the effects of environmental pollution in health. This study investigated the effects on the reproductive system of balb-c mice exposed to water from a river near a deactivated waste depositary. Eighty male mice were separated in four groups: Group A (mineral water); Group B (water from the water treatment station); Group C (water from Cubatao city); Group D (water from the waste depositary region). They were exposed to water since they were weaned until they reached sexual maturity. They were coupled with females in reproductive age and after this mating time they were sacrificed. The evaluated parameters had been testicle weight, sperm analysis, pregnancy rate, sex ratio of the offspring and Sertoli cell count. The analysis of the water did not show presence of pollutants in the group a and group c water. Group b showed low levels of cadmium, 3,58 ± 0,50 g/L and 2,92 ± 0,10g/L. Group d showed the presence of PAHs and high levels of lead (113 ± 11 g/L and 221 ± 16 g/L), cadmiun (11,33 ± 0,50 g/L and 12,6 ± 1,2 g/L) and mercury (4,58 ± 0,92 g/L and 5,3 ± 1,1 g/L . The tests of Levene and Kolmogorov-Smirnov had been used to verify the homogeneity of the variances and the tack to the normal curve, respectively. The parametric tests used ANOVA and the non parametric tests used Kruskall-Wallis test and the test of multiple comparisons of Tukey (Kleibaun). Results: There were no differences between groups in testicle weight, sperm analysis, pregnancy rate and Sertoli cell count. There was a significant reduction in sex-ratio of the offspring in group b. This alteration cannot be explained by the cadmium levels in group b water. In the present work we cannot associate the exposition to water from the waste depositary and reproductive alterations

Les processus de prises de décisions, et les comportements que les animaux adoptent à l'issue de ces processus, ont nécessairement des conséquences sur leurs chances de survivre et de se reproduire. Dans un environnement variable, l'utilisation d'informations fiables apparaît donc comme essentielle pour maximiser sa valeur adaptative. Dans le cadre théorique de la sélection sexuelle, l'objectif principal de la thèse est de comprendre les informations utilisées par les hyménoptères parasitoïdes lors des différentes étapes de la séquence d'appariement et de l'allocation aux sexes. Le manuscrit débute par une importante synthèse bibliographique puis présente les expériences menées en laboratoire et sur le terrain, en prenant l'exemple du parasitoïde solitaire Venturia canescens. Les résultats soulignent l'importance cruciale des informations liées aux conspécifiques lors de la phase d'acquisition des partenaires. Lors de la localisation du partenaire sexuel, les mâles augmentent leur efficacité de recherche en combinant l'information olfactive émise par les femelles à celle reliée à leurs habitats. Lors du choix du partenaire sexuel, les femelles reconnaissent et évitent de s'accoupler avec leurs frères, probablement sur la base d'une signature chimique, ce qui s'explique par le coût délétère des accouplements consanguins chez cette espèce. Comme chez de nombreuses espèces de parasitoïdes, la sex-ratio est biaisée en faveur des femelles, mais contrairement aux prédictions des modèles théoriques, le choix du sexe de la descendance ne semble pas dépendre des informations liées aux conspécifiques. Des contraintes physiologiques pourraient être responsables de ce biais.

<p>Males and females differ in morphology and behaviour, so that selection acts differently on the two sexes. This changes the relative reproductive success of males and females, and it is beneficial for parents to bias the sex ratio of their broods in favour of the sex with the best survival and breeding prospects. Differences between the sexes and brood sex ratio in Tengmalm’s owl (Aegolius funereus) in northern Sweden were investigated, using a molecular sexing technique based on PCRamplification of sex-linked CHD1 genes. Among owls caught during autumn migration, females were commoner than males, especially within juveniles. However, in contrast to earlier studies, it was shown that adult males sometimes undertake migratory movements indicatory of nomadism. Measurements of these owls revealed that sexual size dimorphism in Tengmalm’s owl is not as great as previously reported from studies carried out during the breeding season. Females were slightly larger (4% by mass) than males, probably owing to the different roles of males and females during breeding, when this dimorphism is greater. The size difference between male and female nestlings was found to be similar to that for adults in autumn, and to investigate whether this led to differential mortality, the effect of supplementary feeding on mortality of male and female nestlings was studied. Supplementary feeding reduced male mortality when vole abundance was low, and it was concluded that larger female nestlings out-competed their smaller brothers, who then suffered increased mortality when food was scarce. Recruitment of male nestlings into the breeding population declined with decreasing food supply at the time of fledging, a pattern not observed in females. Juvenile males were therefore more vulnerable to food shortage than females, both in the nest and after fledging. Mean brood sex ratio varied significantly among years characterized by different phases of the vole cycle and associated vole abundance. Broods were male-biased (63% males) in a year when the food supply was favourable during spring and summer, neutral (50%) in a year with an intermediate food supply, and female-biased (35% males) in a year when food was in short supply. Parents appeared to adaptively adjust the sex ratio of their broods according to the relative mortality risk and reproductive potential of sons and daughters.</p>

Males and females differ in morphology and behaviour, so that selection acts differently on the two sexes. This changes the relative reproductive success of males and females, and it is beneficial for parents to bias the sex ratio of their broods in favour of the sex with the best survival and breeding prospects. Differences between the sexes and brood sex ratio in Tengmalm’s owl (Aegolius funereus) in northern Sweden were investigated, using a molecular sexing technique based on PCRamplification of sex-linked CHD1 genes. Among owls caught during autumn migration, females were commoner than males, especially within juveniles. However, in contrast to earlier studies, it was shown that adult males sometimes undertake migratory movements indicatory of nomadism. Measurements of these owls revealed that sexual size dimorphism in Tengmalm’s owl is not as great as previously reported from studies carried out during the breeding season. Females were slightly larger (4% by mass) than males, probably owing to the different roles of males and females during breeding, when this dimorphism is greater. The size difference between male and female nestlings was found to be similar to that for adults in autumn, and to investigate whether this led to differential mortality, the effect of supplementary feeding on mortality of male and female nestlings was studied. Supplementary feeding reduced male mortality when vole abundance was low, and it was concluded that larger female nestlings out-competed their smaller brothers, who then suffered increased mortality when food was scarce. Recruitment of male nestlings into the breeding population declined with decreasing food supply at the time of fledging, a pattern not observed in females. Juvenile males were therefore more vulnerable to food shortage than females, both in the nest and after fledging. Mean brood sex ratio varied significantly among years characterized by different phases of the vole cycle and associated vole abundance. Broods were male-biased (63% males) in a year when the food supply was favourable during spring and summer, neutral (50%) in a year with an intermediate food supply, and female-biased (35% males) in a year when food was in short supply. Parents appeared to adaptively adjust the sex ratio of their broods according to the relative mortality risk and reproductive potential of sons and daughters.

Captive husbandry programs in zoos have documented nesting behavior and have successfully hatched Manouria emys emys, but data on sex determining mechanisms and sex ratios are absent. A total of 30 M. e. emys eggs were artificially incubated at five different temperatures in constant humidity. Mean incubator temperatures were 24.99°C, 25.06°C, 27.18°C, 28.00°C, and 30.79°C. Incubation duration ranged from 60 days to 92 days, and hatching success was 50%. Sex determined by histology and laparoscopy resulted in male differentiation at low temperatures (24.99°C, 27.18°C) and female differentiation at high temperatures (30.79°C). Pivotal temperature was estimated to be 29.29°C. The following investigation into temperature-dependent sex determination (TSD), including its presence or absence, pattern, and pivotal temperature, has implications for studies of adaptive significance of reproductive behaviors and of chelonian phylogenetic history. Additionally, the proposed study can provide foundations for conservation management decisions, and for captive breeding programs.