A wide variety of factors are predicted to influence the intensity and outcome of agonistic interactions in animals, including the resource holding potential of the opponents and the nature and value of the resource over which the individuals are competing. Field crickets (Orthoptera: Gryllidae) have been used extensively as model organisms with which to study animal contests, but relatively few studies have examined the effect of mandible size or structure, or the level of contact with females on the intensity and outcome of agonistic interactions. To do so was the aim of the present thesis, using Gryllus bimaculatus as the study species. The first finding of this study was that there is a significant degree of sexual dimorphism for anterior components of the anatomy in G. bimaculatus. The mandibles, head and pronotum of male crickets were all relatively larger than those of females. This indicates that these traits may be acted upon by intrasexual selection. In many animal species that show sexual dimorphism, a trade-off in development sees enhanced weapon growth at the expense of testes size, but no such relationship was seen in this species. A comparison of the mandible structure of males that either won or lost at flaring and or wrestling showed that a relatively wider mandible span was a significant predictor of success during mandible displays. It was also found that specific components of tooth structure, namely the length of the incisor and length to distal tip, were significantly associated with victory at the jaw flaring stage. This is the first time that mandible shape has been shown to affect fight outcome in the Gryllidae, and also the first confirmed identification of a visual cue component of fighting behaviour. Despite the effectiveness of their weapons in fighting, body mass is a primary predictor of victory in combat between G. bimaculatus males, with the greater the degree of asymmetry in weight the more likely the heavier fighter will win. However, a study of fighting behaviour between asymmetrically matched opponents found that even males who were out-weighed by 40% were still likely to escalate the fight to grappling. Furthermore, males who were able to fend off their larger opponent in their first clash were significantly more likely to win their overall encounter. This hyper-aggressive response may therefore represent an adaptive mechanism to extreme odds and is worthy of further study. Female contact is known to be a significant promoter of male aggression and fighting enthusiasm, and mate guarding aggression is well documented in G. bimaculatus. A recreation of two contradictory studies, including one which concluded that mating makes males lose fights, highlighted that female contact after spermatophore transfer can overcome the loser effect and cause a male to re-engage with a previously dominant opponent. Fighting behaviour in this species is therefore highly flexible and factors affecting the outcome of contests are complex. There is much scope for further studies on this topic.

No description available.

Após a inseminação artificial, as fêmeas apresentam reação inflamatória transitória e fisiológica, que pode resultar em alterações na vascularização uterina. A ultrassonografia Doppler colorido é uma técnica não invasiva, que vem sendo utilizada para estudar a hemodinâmica do trato reprodutivo de bovinos. Os objetivos deste trabalho foram verificar a resposta inflamatória uterina por ultrassonografia Doppler colorido e a taxa de fertilidade em bovinos após inseminação artificial (IA) com sêmen avaliado por sondas fluorescentes. Para isso foram delineados dois experimentos. O experimento 1 foi realizado para estudar a hemodinâmica uterina por ultrassonografia Doppler colorido em bovinos após a IA. Foram utilizadas 18 vacas da raça Nelore, submetidas a um protocolo para a inseminação artificial em tempo fixo (IATF) e divididas em dois grupos: Grupo não inseminado (controle, GC, n=9) e grupo submetido à inseminação artificial (GIA, n=9). Avaliações por ultrassonografia foram realizadas em cinco momentos em modo espectral (30 horas antes da IA, 4, 24, 48 e 168 horas após a IA) para avaliar o índice de resistência (RI) da artéria uterina e em quatro momentos em modo color Doppler (4, 24, 48 e 168 horas após a IA) para avaliar a vascularização dos cornos uterinos. O diagnóstico de gestação foi feito após 30 dias da IA. No experimento 2 objetivou-se verificar se o percentual de espermatozóides com integridade das membranas plasmática e acrossomal e função mitocondrial (PIAIC) avaliadas por sondas fluorescentes influencia a fertilidade e estudar a hemodinâmica uterina após a deposição do sêmen com diferentes percentuais de espermatozóides PIAIC. Foram utilizadas 182 vacas paridas da raça Nelore, submetidas a um protocolo para IATF e divididas em três grupos de acordo com a qualidade do sêmen: Bom (B) 44,5%, Médio (M) 23% e Regular (R) 8,5% de espermatozóides PIAIC/palheta. Uma amostra de 30% das fêmeas (54, sendo 18 de cada grupo) foram submetidas a avaliações com ultrassonografia Doppler colorido 30 horas antes da IA, 4 e 24 horas após a IA. Foram considerados os RI das artérias uterinas direita (AD) e esquerda (AE) e vascularização subjetiva dos cornos uterinos direito (CD) e esquerdo (CE). Posteriormente, foram separados levando em consideração o lado do ovário contendo o folículo dominante para comparar RI das artérias ipsi (AI) e contralateral (AC) e vascularização subjetiva dos cornos uterinos ipsi (CI) e contralateral (CC). O diagnóstico de gestação foi realizado 30 dias após a IA. Para a análise estatística foi utilizado o programa SAS versão 9.2 (SAS 2010). As variáveis foram analisadas pelo PROC MIXED, utilizando modelo linear misto para medidas repetidas no tempo. Foram considerados os efeitos fixos de grupo, tempo e interação grupo x tempo. Os dados obtidos foram submetidos à análise de variância e ao teste de Duncan, pelo PROC GLM. A análise de Qui-Quadrado foi utilizada para determinar a taxa de prenhez, de acordo com a qualidade do sêmen pelo PROC FREQ. O nível de significância considerado foi de 5%. No experimento 1 não foram observadas diferenças dos parâmetros avaliados por ultrassom Doppler entre GIA e GC, mas foram notados efeitos do tempo para RI, sendo mais baixos 4 horas após a IA. Quando os dados foram avaliados de acordo com o lado do folículo dominante foi observado que 4 e 24 horas após a IA, RI da AC do GIA foi mais baixo do que o GC. No experimento 2 não houve diferença entre os animais inseminados com sêmen B, M ou R quanto a hemodinâmica uterina, mas houve efeito do tempo, sendo que 4 horas após a IA verificou-se menor valor de RI e maior fluxo sanguíneo. A taxa de prenhez dos animais inseminados com o sêmen B (64,7%) foi maior quando comparada ao sêmen R (36,2%), sendo que ambos não diferiram do sêmen M (50,0%). Pode-se concluir que não é possível detectar por ultrassonografia Doppler alterações na hemodinâmica uterina devido à IA em fêmeas bovinas. A deposição de sêmen com diferentes qualidades não altera a hemodinâmica uterina de forma detectável por ultrassonografia Doppler em bovinos. Por outro lado, é possível detectar por ultrassonografia Doppler mudanças na perfusão sanguínea do útero em relação ao tempo da IA, o que pode ser devido a alterações hormonais que ocorrem durante o ciclo estral. Por fim, a IA com sêmen contendo menor percentual de espermatozoides PIAIC causa redução na taxa de fertilidade em bovinos. / After insemination, females have physiological and transient inflammatory reaction, which can result in changes in the uterine vasculature. The color Doppler ultrasound is a noninvasive technique that has been used to study the hemodynamics of cattle reproductive tract.The purposes of this work were to verify uterine inflammatory response by color Doppler ultrasound and fertility rate in cattle after artificial insemination (IA) with semen evaluated by fluorescent probes. For this, two experiments were delineated. The first experiment was conducted to study the uterine hemodynamic by color Doppler ultrasound in cattle after AI. Were used 18 Nellore cows that were subjected to a protocol for fixed timed artificial insemination (IATF). The animals were divided in two groups: Not inseminated group (control, GC, n=9) and inseminated group (GIA, n=9). Ultrasonografic evaluation were done in five moments on spectral mode (30 hours before AI, 4, 24, 48 e 168 hours after IA) to evaluate the resistence index (RI) of uterine artery and in four moments in color Doppler mode to evaluate the uterine horns vascularization. The pregnancy diagnostic was done 30 days after IA. In the second experiment the objective was to evaluate whether the percentage of sperm with plasma membrane integrity and acrossomal and mitochondrial function (PIAIC) assessed by fluorescent probes influences fertility and study the uterine hemodynamic after the deposition of semen with different percentages of PIAIC sperm. Were used 182 caved Nellore cows submitted to a protocol for IATF and divided into three groups according to semen quality: Good (B) 44.5%, Medium (M) 23% and Regular (R) 8,5% of PIAIC sperm/blade. A sample of 30% of female (54, 18 in each group) were submitted to evaluation by color Doppler ultrasound 30 hours before IA, 4 and 24 hours after IA. Were considered RI of right (AD) and left (AE) uterine arteries and subjective vascularization of right (CD) and left (CE) uterine horns. Later, they were separated taking into account the side of the ovary containing the dominant follicle to compare RI of ipsi (AI) and contralateral (AC) arteries and subjective vascularization of ipsi (CI) and contralateral (CC) uterine horns. The pregnancy diagnostic was done 30 days after IA. Statistical analysis was performed using the program SAS version 9.2 (SAS 2010). The variables were analyzed by PROC MIXED, using mixed linear model for repeated measures in time. We considered effects of group, time and group x time interaction. The data obtained were submitted to ANOVA and Duncan test, using PROC GLM. The chi-square analysis was used to determine pregnancy rate, according to the quality of semen by PROC FREQ. the significance level was 5%. In experiment 1 there were no differences of the parameters evaluated by Doppler ultrasound between GIA and GC, but time effects were noted for RI, it was lower four hours after IA. When the data were evaluated according to the side of the dominant follicle was observed that 4 and 24 hours after IA, RI of AC of GIA was lower when it was compared with GC. In experiment 2 there was no difference between animals inseminated with semen B, M or R about uterine hemodynamics, but there were effects of time, so that 4 hours after IA showed lower value of RI and increased blood flow. The pregnancy rate of animals inseminated with semen B (64.7%) was higher when compared with semen R (36.2%), both of them did not differ of semen M (50.0%). It can be concluded that is not possible to detect uterine hemodynamic changes by Doppler ultrasound due to IA in cattle. The deposition of semen with different qualities does not change the uterine hemodynamics enough to be detectable by Doppler ultrasonography in cattle. On the other hand, is possible to detect changes in blood perfusion of the uterus in relation to the time of IA by Doppler ultrasound, which may be due to hormonal changes that occur during the estrous cycle. Finally, IA with semen containing a lower percentage of PIAIC sperm causes a reduction in fertility rate in cattle.

Territórios resultam de competição por interferência que leva ao uso exclusivo do espaço. A territorialidade então depende da variação espaço-temporal na disponibilidade de recursos e está, geralmente, associada ao sistema de acasalamento. A defesa de território deve ocorrer quando os benefícios superam os custos, e essa relação custo-benefício deve ser afetada por fatores ecológicos (disponibilidade de recursos e densidade populacional), assim como variações individuais (sexo e maturidade) e sazonais (época reprodutiva) que determinam quais e quando os recursos são importantes. Embora as estratégias territoriais dos indivíduos devam variar com as condições ambientais, potencialmente levando a diferentes sistemas territoriais⁄ de acasalamento em diferentes populações, estudos prévios sobre territorialidade geralmente avaliam somente uma população e⁄ou consideram condições ambientais relativamente homogêneas. Utilizando um banco de dados extenso de captura-marcação-recaptura em 9 populações de um roedor generalista (Akodon montensis), e usando a sobreposição da área de vida como proxy de não-territorialidade, pretendemos entender os determinantes ecológicos, individuais e sazonais das estratégias territoriais dos indivíduos, e avaliar se a variação nas estratégias individuais pode levar a uma transição entre sistemas territoriais⁄ de acasalamento. Como previsto, identificamos que a sobreposição das áreas de vida foi maior entre machos do que entre fêmeas e aumentou com a densidade populacional. Também aumentou de machos imaturos para machos maduros, mas diminuiu de fêmeas imaturas para fêmeas maduras, sugerindo que a diferença na territorialidade entre os sexos é definida após a maturidade sexual. O efeito negativo da disponibilidade de fêmeas na sobreposição da área de vida entre machos foi mais forte na época reprodutiva, como esperado. Mais importante, no entanto, o efeito da disponibilidade de fêmeas na sobreposição da área de vida foi fortemente dependente do sexo. À medida que a disponibilidade de fêmeas aumenta, a sobreposição da área de vida aumentou entre fêmeas, mas diminuiu entre machos, indicando que quando as fêmeas deixam de defender território (e ficam mais agregadas) devido ao aumento da competição entre elas, os machos passam a defender território. Nosso estudo ressalta que as estratégias territoriais são muito variáveis entre indivíduos, o que é consistente com a plasticidade ecológica e fisiológica em Akodon montensis reportada em outros trabalhos, e sugere que diferenças suficientes nas condições ambientais podem levar à transição entre sistemas territoriais⁄ de acasalamento / Territories result from interference competition that leads to exclusive use of space. Territoriality thus depends on the spatial and temporal variation in resource availability, and is usually associated with mating systems. Territorial defense should occur when benefits outweigh costs, and this balance should be determined by ecological factors (resource availability and population density), as well as individual (gender and sexual maturity) or seasonal (breeding season) variations that determine which and when resources are important. Although individual territorial strategies should vary with changing environmental conditions, possibly leading to multiple territorial⁄mating systems among populations, previous studies on territoriality focused mostly on single populations and/or on relatively homogeneous environmental conditions. Relying on an extensive capture-recapture dataset from 9 populations of a generalist rodent (Akodon montensis), and using home range overlap as a proxy of non-territoriality, we aim to understand the ecological, individual and seasonal determinants of individual territorial strategies, and investigate whether variation in individual strategies can lead to transitions between territorial⁄mating systems. We identified that home range overlap was larger between males than females and increased with population density, as expected. It also increased from immature to mature individuals among males, but the opposite was true among females, suggesting that differences in territoriality between genders is established after sexual maturity. The negative effect of female availability on home range overlap between males was stronger in the breeding season, as expected. More importantly, though, the effect of female availability on home range overlap was strongly gender dependent. As female availability increased, home range overlap increased between females but decreased between males, suggesting that when females become non-territorial (and thus more aggregated) because of increased competition with other females, males become territorial. Our study highlights territorial strategies are extremely variable among individuals, which is consistent with previously reported ecological and physiological plasticity in Akodon montensis, and suggests that sufficient changes in environmental conditions could lead to transitions between territorial⁄mating systems

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

Le champignon filamenteux, Podospora anserina, possède deux types sexuels, mat+ et mat-, caractérisés chacun par une séquence spécifique. La séquence mat+ contient un seul gène FPR1; la séquence mat- contient trois gènes : FMR1, SMR1 et SMR2. La fonction moléculaire de SMR1 est inconnue, les autres gènes codent des facteurs de transcription qui contrôlent la fécondation (reconnaissance intercellulaire), et le passage d’un syncytium à un hyphe spécialisé binucléé contenant un noyau mat+ et un noyau mat- (reconnaissance internucléaire). Il n’y a pas eu d’analyse exhaustive des gènes impliqués dans la reconnaissance intercellulaire et le mécanisme de la reconnaissance internucléaire est encore inconnu. Afin de déterminer les cibles de FPR1 et FMR1, et les différents mécanismes impliqués, nous avons utilisé une approche microarray. Le profil transcriptomique des souches mat+ et mat- compétentes pour la fécondation a permis d’identifier 157 gènes cibles, et l’analyse transcriptomique des souches mutantes fpr1- et fmr1- a révélé que ces cibles peuvent être soit réprimées, soit activées par FMR1 ou FPR1, ou être sous le contrôle de ces deux facteurs. Ces expériences ont aussi détecté l’existence de 10 gènes activés ou réprimés au même niveau dans mat+ et mat-. La délétion de 32 gènes choisis parmi ces 167 gènes cibles n’a permis de mettre en évidence que deux gènes impliqués dans la fécondation. Les comparaisons des gènes cibles des facteurs de transcription MAT de Gibberella moniliformis et Sordaria macrospora avec ceux de P. anserina révèlent un nombre significatif de gènes cibles communs entre ces espèces, mais ces gènes ont des profils transcriptomiques différents, soulevant la question du rôle de ces gènes cibles. La recherche des gènes cibles de FPR1, FMR1 et SMR2 impliqués dans la reconnaissance internuléaire a été effectuée en comparant le transcriptome des périthèces issus de deux croisements, l’un n’exprimant que les gènes spécifiques mat+, l’autre que les gènes spécifiques mat-. Les résultats ont été interprétés selon le modèle d’identité nucléaire et le modèle de ségrégation aléatoire. Le premier modèle a conduit à l’identification de 27 gènes cibles, tandis que 154 gènes cibles ont été identifiés en appliquant le deuxième modèle. Au total 46 souches mutantes ont été construites. Cependant aucune délétion n’a affecté le développement sexué. En parallèle de ces expériences transcriptomiques, nous avons invalidé tous les gènes à HMG-box de P. anserina. Les résultats montrent que ces derniers ont un rôle très important dans le développement sexué, particulièrement Pa_1_13940 qui code un régulateur des gènes des types sexuels, le premier identifié chez les Pezizomycotina. / The filamentous fungus, Podospora anserina, has two mating-type idiomorphs, mat+ and mat-. The mat+ sequence contains one gene FPR1, while mat- contains three genes: FMR1, SMR1 and SMR2. The molecular function of SMR1 is unknown, FPR1, FMR1 and SMR2 encode transcriptional regulators which control the fertilization (intercellular recognition) and the transition from a syncytium to a specialized dikaryotic hypha which contains one mat+ and one mat- nucleus (internuclear recognition). No exhaustive analysis is available for the genes involved in the intercellular recognition, while the mechanism of the internuclear recognition is unknown. In order to understand the mechanism of these events and to identify the target genes of mating-type transcription factors, we used a microarray approach. The transcriptomic profiles of the mat+ and mat- strains that are competent for fertilization revealed 157 differentially transcribed genes, and transcriptomic analysis of fmr1- and fpr1- mutant strains was used to determine the regulatory actions exerted by FMR1 and FPR1 on these differentially transcribed genes. All possible combinations of transcription repression and/or activation by FMR1 and/or FPR1 were observed. Furthermore, 10 additional mating-type target genes were identified that were up- or down-regulated to the same level in mat+ and mat- strains. Of the 167 genes identified, 32 genes were selected for deletion, which resulted in the identification of two genes essential for the sexual cycle. A comparison with similar data set from the two ascomycetes, Gibberella moniliformis and Sordaria macrospora, reveals significant numbers of orthologous pairs, although transcriptional profiles were not conserved between species, questioning the function of these target genes. Internuclear recognition was investigated by the transcriptomic analysis of perithecia from two crosses expressing mat+ and mat- genes, respectively. The tow internuclear recognition models: nuclear identity and random segregation, were used to interpret our results. According to the former model, 27 target genes have been identified, while 154 target genes were identified with the latter model. A total of 46 mutant strains were constructed. However, these strains showed no defects in sexual development. Besides this microarray experiences, we have invalidated all HMG-box genes of P. anserina. The results show that the HMG-box genes have a very important role in sexual development, especially Pa_1_13940 which encodes the first identified regulator of Pezizomycotinan mating-type genes.

As abelhas são insetos da ordem Hymenoptera e taxonomicamente estão reunidas na superfamília Apoidea. Os Meliponini, da subfamília Apinae, são popularmente chamados abelhas indígenas sem ferrão e algumas espécies são essenciais para a polinização de plantas selvagens e lavouras. As abelhas Nannotrigona testaceicornis, utilizadas neste trabalho, são pequenas, possuem o tórax marrom escuro e opaco e não são agressivas. No Brasil, elas são encontradas na Bahia, Espírito Santo, Goiás, Minas Gerais, Rio de Janeiro e São Paulo. Assim como muitas espécies de Hymenoptera, elas também podem nidificar em agregações e analisar a variabilidade genética dentro e entre os agregados foi um dos objetivos deste trabalho, além de avaliar os prováveis múltiplos acasalamentos que parecem ocorrer dentro dessa espécie de meliponíneos. Para tanto, foram coletados indivíduos de ninhos de N. testaceicornis no Campus da USP de Ribeirão Preto (SP), Campinas (SP), Bonfim Paulista (SP), Uberlândia (MG) e Caratinga (MG). 302 indivíduos (operárias) de um total de 32 ninhos foram macerados e tiveram seu DNA extraído. Foram utilizados oito loci microssatélites específicos para o estudo da variabilidade genética e múltiplos acasalamentos. Um total de 38 alelos foi observado. A diversidade genética média entre as agregações foi de 35,4%, a heterozigose média esperada foi de 41,4% e a observada foi de 28,3%. O coeficiente de endogamia (Fis) foi estatisticamente significativo para todas as agregações. Também foram observados desvios no equilíbrio de Hardy-Weinberg para todos os loci analisados. A análise do Fst mostrou diferenciação entre as agregações, porém, apesar da indicação pelo AMOVA de uma discreta estruturação entre as agregações, não foi possível agrupá-las. A partir dos dados obtidos foi possível observar que a diversidade genética nestas agregações está baixa, além disso, os desvios do equilíbrio, o valor significativo do Fis, e a heterozigose observada menor do que a esperada em todos os loci demonstrou a ocorrência de cruzamentos endogâmicos resultando em alto nível de homozigose nesta população. Com relação aos múltiplos acasalamentos, dos 32 ninhos estudados, somente 11 (34,4%) apresentaram uma patrilínea. A presença de alelos nulos, a inclusão acidental de machos na amostra, mudanças recentes de rainhas, operárias de outros ninhos e a contínua conexão entre ninho mãe-filho podem ser possibilidades para estes resultados, entretanto, a frequência de mais de uma patrilínea é muito alta para que a poliandria não seja considerada. / Bees are insects belonging to the Hymenoptera order and to the Apoidea superfamily. The Meliponini, from the subfamily Apinae, are popularly known as stingless bees and some species are essential to the pollination of wild and farming plants. Nannotrigona testaceicornis, studied in this work, are small bees presenting a dark brown and opaque thorax, and non-aggressive behavior. In Brazil, they are found at Bahia, Espírito Santo, Goiás, Minas Gerais, Rio de Janeiro and São Paulo states. As well as many other Hymenoptera species, they can nest on aggregations. To analyze the genetic variability within and among the aggregates was one of the objectives of this work, besides to evaluate the possibility of multiple matings which seem to occur in this species. For this purpose, samples of N. testaceicornis were collected from nests found at University of São Paulo Campus at Ribeirão Preto (SP), Campinas (SP), Bonfim Paulista (SP), Uberlândia (MG) and Caratinga (MG). Three hundred and two individuals (workers) from thirty-two sampled nests had their DNA extracted. Eight specific microsatellite loci were used to study the genetic variability and multiple matings. A total of thirty-eight alleles were observed. The mean genetic diversity among the aggregations was 35.4%, the mean expected heterozygosity was 41.4% and the observed was 28.3%. The inbreeding coefficient (Fis) was statistically significant for all the aggregations. Deviations from Hardy-Weinberg Equilibrium were observed in all studied loci. The Fst analysis showed differentiation among the aggregations but, despite the AMOVA indication of structuring among them, it was not possible to group them. From the obtained data we observed that the genetic diversity of the aggregations is low. The significant Fis value and the observed heterozygosity lower than the expected one in all the studied loci, demonstrated inbreeding events resulting in a high level of homozygosis in this population. In relation to the possibility of multiple mating, from the 32 studied nests, only 11 (34.4%) presented one patriline. The presence of null alleles, the accidental inclusion of males in the sample, recent queen changes, workers drifting among nests, continuing connections between mother and daughter nests or multiple matings might be possibilities for these results. However, the frequency of more than one patriline is very high to not consider the polyandry.

Plant pathogens have the ability to quickly overcome host resistance and shift to novel hosts. The (re)emergence of plant pathogens is a major concern in agriculture and in conservation of natural landscapes. The rapid adaptation to hosts and new environments depends on the genetic variability in pathogen populations. Despite of the importance of sugarcane for Brazilian agribusiness and the persistence of the smut pathogen Sporisorium scitamineum in most cropping areas, genetic variation studies are still missing for Brazilian isolates. In the chapters 1 and 2, molecular variability studies were performed for Brazilian and Argentine isolates of S. scitamineum, using molecular markers (AFLP, telRFLP) and sequencing (ITS and a candidate effector gene) strategies. No variation was found in ITS sequences. On the contrary, telRFLP marker generates almost a unique fingerprint for each strain. Two genetically distinct groups were formed by the joint analysis of the AFLP and telRFLP markers. The two groups were the same formed by haplotypes of a candidate effector gene. The presence of polymorphisms that causes non-synonymous mutations in a candidate effector gene potentially involved in the specific interaction with sugarcane may cause distinct performances on host genotypes. S. scitamineum is part of the highly diverse clade of Ustilaginomycetes fungi that includes several smut disease agents. Despite being phylogenetically close and present similar lifestyles, species of smut fungi have distinct and narrow host ranges. Hence, another objective in this thesis was to identify the genetic basis of host specialization in smut fungi using comparative genomics analyses. In chapter 3, the mating-type loci were described in S. scitamineum genome and compared among smut fungi. Transposable elements are the likely mechanism causing chromosomal rearrangements between mating-type loci. The presence of trans-specific polymorphisms at the genes encoding pheromone/receptor proteins suggests a hybridization potential among smut species. In the chapter 4, a broad comparative genomics analysis was performed among nine species of smut fungi infecting distinct hosts. The genetic basis of host specialization in smut fungi is complex and seems to involve a range of evolutionary processes, including gene gain/loss and episodic selection events. Species-specific effectors and positively selected genes will be good candidates for further characterization in regards to their role in host adaptation. / Fitopatógenos apresentam a habilidade de rapidamente suplantar os mecanismos de defesas da planta e adaptar-se a um novo hospedeiro. A (re)emergência de patógenos é uma das maiores preocupações na agricultura e na conservação de populações naturais. A rápida adaptação ao hospedeiro e a novos ambientes depende da variabilidade genética nas populações de patógenos. Apesar da importância da cana-de-açúcar para o agronegócio brasileiro e da persistência do patógeno Sporisorium scitamineum, o agente causal do carvão da cana-de-açúcar, na maioria das áreas canavieiras, estudos de variabilidade genética ainda não foram realizados para isolados brasileiros. Nos capítulos 1 e 2, estudos de variabilidade molecular foram realizados para isolados brasileiros e argentinos de S. scitamineum, usando marcadores moleculares (AFLP e telRFLP) e dados de sequenciamento (ITS e um gene candidato a efetor). Nenhum polimorfismo foi encontrado usando sequências ITS. Contrariamente, o marcador telRFLP gerou quase um fingerprint para cada linhagem. Dois grupos geneticamente distintos foram formados pela análise conjunta dos marcadores telRFLP e AFLP. Os dois grupos também foram formados pelos haplótipos obtidos pelo sequenciamento de um candidato a efetor. A presença de polimorfismos causando mutações não-sinônimas em um candidato a efetor pode acarretar em performances distintas em diferentes genótipos de cana-de-açúcar. S. scitamineum pertence à classe Ustilaginomycetes, a qual também abrange vários outros agentes causais de doenças do carvão. Apesar de filogeneticamente próximos e com estilo de vida similar, espécies de carvão apresentam uma faixa distinta e estreita de hospedeiros. Portanto, outro objetivo desta tese foi identificar a base genética da especialização ao hospedeiro por fungos causadores de carvão usando análises de genômica comparativa. No capítulo 3, os loci envolvidos na determinação do tipo de reação sexual (mating-type) foram caracterizados no genoma de S. scitamineum e comparados com sequências de outras espécies de carvão. Tranposons foram identificados como provável mecanismo de rearranjo cromossômico entre os loci de mating-type. Polimorfismos trans-específicos nos genes codificadores de feromônios e receptores sugerem o potencial de hibridização entre espécies de carvão. No capítulo 4, análises de genômica comparativa abrangendo nove espécies de carvão infectando hospedeiros distintos foram realizadas. A base genética da especialização ao hospedeiro em fungos causadores de carvão é complexa e parece envolver processos evolutivos de ganho/perda de genes e seleção positiva. Efetores espécie-específicos e sob seleção positiva são destacados como bons candidatos para serem caracterizados quanto ao papel que estabelecem na adaptação ao hospedeiro.

Na presente tese estudei a biologia de Centris (Paracentris) burgdorfi, uma abelha solitária de ampla distribuição no Brasil. O único local de nidificação conhecido até o momento fica em uma área de dunas, no nordeste do Brasil, à 25 km da cidade de Natal. Neste local as fêmeas nidificam exclusivamente em paleodunas à cerca de 1 km do mar. Estudei o sistema de acasalamento da espécie, onde pude constatar que a alta competição por fêmeas próxima ao ninho faz com que o macho tenha que retirar a fêmea do local para conseguir o contato genital. Nenhuma fêmea foi vista acasalando mais de uma vez e, logo após a cópula a fêmea dá início à construção do ninho. O ninho é constituído de um túnel raso com acesso às células de cria, construídas uma ao lado da outra. Avaliei o número de viagens que a fêmea faz para a coleta de óleo e pólen e o tempo despendido em cada ação dentro do ninho (deposição de pólen, óleo, ovoposição e operculação). Durante o período de construção das células as fêmeas não dormem dentro do ninho, e sim, em ramos de Krameria tomentosa, a planta utilizada como fonte de óleo no local. Buscando ampliar nosso conhecimento sobre a espécie, procurei outras populações no Brasil para que pudesse avaliar o nicho trófico. Utilizei o pólen encontrado no corpo das fêmeas para inferir sobre a dieta parcial de adultos e imaturos. Além da área de dunas, no Nordeste, encontramos C. burgdorfi no cerrado em Cavalcante, Goiás e em áreas de campo de altitude, em Ponta Grossa, Paraná. Através da análise polínica, constatei a importância de plantas do gênero Chamaecrista como fonte de pólen, sendo este um dos poucos gêneros compartilhados entre os três locais. Krameria grandiflora foi a fonte de óleo em Cavalcante e em Natal, e Angelonia integérrima, foi a fonte de óleo no Paraná. Isso revela a amplitude de nicho trófico em C. burgdorfi não apenas em relação às espécies de plantas utilizadas na dieta mas, também, quanto ao tipo de elaióforo que a fêmea consegue acessar (epitelial e tricromático). Esta plasticidade possibilita a ampla distribuição da espécie em diferentes fitofisionomias. Analisei nutricionalmente a dieta na provisão da cria de C. burgdorfi do nordeste do Brasil e de células de cria de Centris (Paracentris) pallida, coletadas no sudoeste dos Estados Unidos. Centris pallida é uma espécie de Centridini que perdeu o comportamento da coleta de óleo. Centris burgdorfi possui uma dieta mais rica em lipídeos e proteínas, sendo a dieta de C. pallida mais rica em carboidratos. A dieta mais protéica de C. burgdorfi se deve à presença de Chamaecrista já que plantas que anteras poricidas contem mais proteínas em comparação às não-poricidas, como é o caso das fontes de pólen de C. pallida (Parkinsonia e Olneya) / In the present thesis, I studied the biology of Centris (Paracentris) burgdorfi, a solitary bee of wide distribution in Brazil. The only nesting site known is in a dune area in northeastern Brazil, 25 km from the city of Natal. In this place, the females nest exclusively in petrified dunes about 1 km from the sea. I studied the mating system of the species, where I could verify that the high competition by females near the nest forces the male to carry the female to another place to mate. No female was seen mating more than once and, soon after copulation, the female begins to construct the nest. The nest consists of a shallow tunnel with access to the brood cells. I evaluated the number of trips that the female made to the collection of oil and pollen and the time spent in each action within the nest (depositions of pollen, oil, oviposition and operculation). During the period of construction of the cells the females do not sleep inside the nest, but in branches of Krameria tomentosa, the plant used as source of oil. In order to increase our knowledge about the species, I searched for other populations in Brazil so that I could evaluate the trophic niche. I used pollen found in the body of females to infer about the partial diet of adults and immature. In addition to the dune area in the Northeast, I found C. burgdorfi in the tropical Savanna (Cerrado) in Cavalcante, state of Goiás and in high altitude field areas, in Ponta Grossa, state of Paraná. Through pollen analysis, I verified the importance of plants of the genus Chamaecrista as a source of pollen, being this one of the few genera shared among the three sites. Krameria grandiflora was the source of oil in Cavalcante and in the Natal, and Angelonia integerrima, was the source of oil in the Ponta Grossa. This reveals the trophic niche amplitude in C. burgdorfi not only in relation to the species of plants used in the diet, but also to the type of elaiophore that the female can access (epithelial and trichromatic). This plasticity makes possible the wide distribution of the species in different phytophysiognomies. Nutritionally I analyzed the diet in the provision of C. burgdorfi offspring from northeastern Brazil and from the breeding cells of Centris (Paracentris) pallida collected in the southwestern United States. Centris pallida is a species of Centridini that has lost the behavior of the oil-collection. Centris burgdorfi has a diet richer in lipids and proteins, and the diet of C. pallida is richer in carbohydrates. The most proteinic diet of C. burgdorfi is due to the presence of Chamaecrista, since plants with poricidal anthers contain more proteins compared to non-poricidal ones, such as C. pallida (Parkinsonia and Olneya) pollen sources

The Australian magpie (Gymnorhina tibicen) is a large, sedentary, omnivorous passerine. In some populations, individuals live in groups, and some of these groups breed cooperatively. The white-backed magpie (G. t. tyrannica) from the south-eastern corner of the continent, has had relatively little study, and few details are known of its mating system, social structure, and method of parental care. I conducted an observational study on a population of white-backed magpies, recording details of their demography, dispersal, breeding system, and parental care. In conjunction, I conducted a genetic analysis of the population, to determine if the genetic mating system matched the observed social system, to detect instances of extra-group mating, and to sex juvenile birds. Extra-pair paternity (EPP) is a common feature of the mating systems of many birds. The rate of EPP may vary between species, races and populations. I made a comparison of extra-group paternity (EGP) rates between two races of the Australian magpie, to determine if similar mating systems were being employed. The two populations had similar social structure, but differed in group size and dispersal. I predicted that dispersal differences would have a profound effect on the rate of EGP between the populations, as the population with the lower rate of dispersal and higher chance of breeding with a close relative would engage in EGPs more frequently. Eight microsatellite loci were used to determine parentage in the white-backed Australian magpie. The rate of EGP was found to be 44%. Dispersal rates were estimated from observational data. Over half of the juvenile magpie cohort from the previous breeding season leave the territorial group. These results contrast sharply with the results found by other researchers in a population of western Australian magpies (G t. dorsalis). In this population, 82% EGP is recorded and dispersal of juveniles is close to nil. The results indicate that dispersal rate is a potentially important predictor of rates of extra-group fertilisations between populations of this species, and suggest that females maximise their reproductive output by avoiding breeding with close kin. The reproductive success of a male bird is often correlated with measurable traits that predict his intrinsic quality. Females are thought to select mates based on their quality to gain their 'good genes'. Male Australian magpies of the white-backed race were trapped in two breeding seasons. Measurements were taken of morphometric and other characteristics in order to discover whether particular traits of males were associated with: a) number of fledglings produced in the territory per season; b) percentage of offspring sired in the territory; and c) whether females select males for their 'good genes'. The only variable that was correlated with number of territorial offspring was feather lice load. Males with high numbers of lice were less likely to produce territorial fledglings in one season and across both seasons. Males of inferior quality may be subject to increased conspecific territorial intrusions, leading to more time spent on defence, more failed breeding attempts, less time allocated to grooming and thus high parasite loads. Males that produced many territorial fledglings were more likely to gain genetic paternity of at least some of them, although again this was significant for only one season. Also, across both seasons, a high number of females in the group was correlated with increased paternity within the group. The general lack of correlation between the variables and level of genetic paternity may be due to females engaging in extra-group mating primarily to avoid breeding with a close relative rather than to choose a quality male. In this scenario, males would not have to be 'high quality', but merely genetically different to the female's social mate. Extra-group paternity (EGP) can affect paternal effort. It may also influence the helping effort of auxiliary birds in cooperatively breeding species. If helping is driven by kin selection, helpers should decline to provision unrelated young. Relatedness becomes difficult to assess however, when females mate outside the group. Alternative rewards may then become important in helper decisions. In my study population of Australian magpies, 38% of fledglings were sired by males outside the territorial group. In a second population (G. t. dorsalis), 82% of fledglings were sired by extra-group males. I observed within-group male and helper feeding effort over three breeding seasons in the first population and obtained data recorded over a single season in the second population. In both populations, males provisioned young regardless of relatedness, as did helpers. Males provisioned less than the nesting female on average. Paternal effort did not reduce with an increase in the rate of EGP between populations. In the population with intermediate levels of EGP, the white-backed magpies, I observed helpers in about half of the sampled territories that produced fledglings. Helpers did not increase the production of young. In the population with high levels of EGP, western magpies, I detected helping behaviour in proportionally more territories. It appears that Australian magpie helpers provide help in order to pay 'rent' and remain on the natal territory. I discuss these results in light of the differences between the two races of magpie and the major theories regarding male parenting decisions and helper activity. Finally, I examine the relatively high rates of EGP's in the Australian magpie from a phylogenetic perspective. Although inbreeding avoidance is strongly supported by this study as the major reason EGP is so common in magpie populations, there may be an element of phylogenetic inertia that maintains the frequency of this behavioural trait. I comment upon the use of single-population estimates of species EGP rates in comparative analyses, given the intraspecific variation discovered between Australian magpie populations. Future directions for the study of mate choice in the Australian magpie are outlined with a proposal to study variation at the major histocompatibility complex between mated pairs.