RESUMO

The northern muriqui (Brachyteles hypoxanthus) is a critically endangered species endemic to the Atlantic Forest of southeastern Brazil. Long-term observational studies of wild muriquis have provided many insights into the behavioral ecology and life history of this species. However, nearly everything that is currently known about the northern muriqui's behavioral endocrinology has come from combining our respective expertise in noninvasive field and laboratory research. Here, we reflect on the history of our collaboration, focusing on major challenges, key scientific findings, and factors that contributed to its success. Challenges included insuring the reliable collection of frequent fecal samples from a large enough number of known individuals over extended periods of time, preserving the steroids in the field and transporting them, developing and validating the fecal steroid assays, and interpreting the hormonal profiles within the behavioral and ecological contexts of the study subjects. Major findings included our thorough description of the fecal progesterone and estradiol profiles associated with muriqui ovarian cycling and gestation, the seasonal resumption of cycling, its onset during puberty of dispersing females, and the differences between fertile and infertile cycles. We also documented the relationship between fecal cortisol and testosterone in sexually active males across breeding and nonbreeding seasons, and sex differences in cortisol levels across the mating and conception seasons. We attribute the success of our collaboration to a number of factors including our mutual appreciation for one another's high standards for ethics, data quality, and data interpretation.

Assuntos

RESUMO

We studied the diet of the ocelot and puma during the years 2007 and 2008 at the Feliciano Miguel Abdala Reserve, in Minas Gerais, south-eastern Brazil. We collected 49 faecal samples (scats) from cats, and identified the species of cat from 23 of them by the analysis of the microstructure patterns of hairs found in their faeces: 17 scats of the puma (Puma concolor) and six of the ocelot (Leopardus pardalis). In the puma scats, we identified three species of primates (Brachyteles hypoxanthus, Alouatta guariba and Sapajus nigritus), the remains of which were found in eight of 17 collected (47.1%), representing 26.7% of items consumed. For the ocelot, we detected capuchin monkey (S. nigritus) remains in three of the six scats (50%), accounting for 18.7% of items consumed by ocelot. We were unable to identify the cat species in the remaining 26 faecal samples, but we were able to analyse the food items present. Primates were found in five of these 26 faeces (19.2%) and represented 10.2% of the items found. Although the sample size is limited, our results indicate a relatively high consumption of primates by felines. We believe that this high predation may be the result of the high local density of primates as well as the greater exposure to the risks of predation in fragmented landscapes, which tends to increase the incidence of the primates using the ground.(AU)

Nós estudamos a dieta de jaguatiricas e onças-pardas entre os anos de 2007 e 2008 na Reserva Feliciano Miguel Abdala, em Minas Gerais, sudeste do Brasil. Nós coletamos 49 amostras fecais de felinos, em 23 das quais foi possível a identificação do predador através da análise do padrão microestrutural dos seus pelos encontrados nas fezes, sendo 17 fezes de onça-parda (Puma concolor) e seis de jaguatirica (Leopardus pardalis). Nas amostras de onça-parda nós identificamos três espécies de primatas (Brachyteles hypoxanthus, Alouatta guariba e Sapajus nigritus), cujas partes não digeridas foram encontradas em oito das 17 fezes coletadas, representando 26,7% dos itens consumidos por onças-pardas. Para jaguatirica, nós detectamos macacos-prego (S. nigritus) em três de seis fezes, o que correspondeu a 18,7% dos itens consumidos. Para as 26 amostras fecais restantes, cuja identificação do predador não foi possível, nós analisamos os itens alimentares presentes. Restos de primatas foram identificados em cinco dessas fezes (19,3%), representando 10,2% dos itens encontrados. Apesar do tamanho da amostra ser limitado, nossos resultados indicam uma taxa relativamente alta de consumo de primatas por felinos. Nós acreditamos que essa alta taxa de predação pode ser resultado da grande densidade local de primatas, bem como do aumento do risco de predação em paisagens fragmentadas, o que tende a aumentar a incidência do uso do chão por parte dos primatas.(AU)

Assuntos

RESUMO

We studied the diet of the ocelot and puma during the years 2007 and 2008 at the Feliciano Miguel Abdala Reserve, in Minas Gerais, south-eastern Brazil. We collected 49 faecal samples (scats) from cats, and identified the species of cat from 23 of them by the analysis of the microstructure patterns of hairs found in their faeces: 17 scats of the puma (Puma concolor) and six of the ocelot (Leopardus pardalis). In the puma scats, we identified three species of primates (Brachyteles hypoxanthus, Alouatta guariba and Sapajus nigritus), the remains of which were found in eight of 17 collected (47.1%), representing 26.7% of items consumed. For the ocelot, we detected capuchin monkey (S. nigritus) remains in three of the six scats (50%), accounting for 18.7% of items consumed by ocelot. We were unable to identify the cat species in the remaining 26 faecal samples, but we were able to analyse the food items present. Primates were found in five of these 26 faeces (19.2%) and represented 10.2% of the items found. Although the sample size is limited, our results indicate a relatively high consumption of primates by felines. We believe that this high predation may be the result of the high local density of primates as well as the greater exposure to the risks of predation in fragmented landscapes, which tends to increase the incidence of the primates using the ground.

Nós estudamos a dieta de jaguatiricas e onças-pardas entre os anos de 2007 e 2008 na Reserva Feliciano Miguel Abdala, em Minas Gerais, sudeste do Brasil. Nós coletamos 49 amostras fecais de felinos, em 23 das quais foi possível a identificação do predador através da análise do padrão microestrutural dos seus pelos encontrados nas fezes, sendo 17 fezes de onça-parda (Puma concolor) e seis de jaguatirica (Leopardus pardalis). Nas amostras de onça-parda nós identificamos três espécies de primatas (Brachyteles hypoxanthus, Alouatta guariba e Sapajus nigritus), cujas partes não digeridas foram encontradas em oito das 17 fezes coletadas, representando 26,7% dos itens consumidos por onças-pardas. Para jaguatirica, nós detectamos macacos-prego (S. nigritus) em três de seis fezes, o que correspondeu a 18,7% dos itens consumidos. Para as 26 amostras fecais restantes, cuja identificação do predador não foi possível, nós analisamos os itens alimentares presentes. Restos de primatas foram identificados em cinco dessas fezes (19,3%), representando 10,2% dos itens encontrados. Apesar do tamanho da amostra ser limitado, nossos resultados indicam uma taxa relativamente alta de consumo de primatas por felinos. Nós acreditamos que essa alta taxa de predação pode ser resultado da grande densidade local de primatas, bem como do aumento do risco de predação em paisagens fragmentadas, o que tende a aumentar a incidência do uso do chão por parte dos primatas.

Assuntos

RESUMO

Although well documented in matrilocal primate species, group fission is still a poorly known phenomenon among patrilocal primates. In this paper we describe in detail a group fission event in the population of northern muriquis at the Reserva Particular do Patrimônio Natural-Feliciano Miguel Abdala in Caratinga, Minas Gerais, Brazil, using Social Network Analyses (SNA). Data on association patterns were collected during systematic observations from May 2002 to September 2005, and analyzed for dry (from May to October) and rainy seasons (from November to April). The fission process started with subgroup formation in the rainy season 2002-2003, and was completed by the dry season of 2003. By the dry season 2003, the parent group (Jaó) had fissioned to form a second mixed-sex group (Nadir) while a subgroup of males (MU) moved between the parent group and the newly established group. Before the Jaó group fission started (dry season 2002) and during its initial phases (rainy season 2002-2003), females that ultimately composed the daughter group (Nadir) were the most peripheral in the association network. In the rainy season 2002-2003, the median monthly (N=6) operational sex ratio (OSR) of Jaó group was 2.81. However, once Jaó females initiated the fissioning process to establish the Nadir group, the OSR was more favorable to males in the Nadir group than in the Jaó group. Our results suggest that males followed the females to escape an unfavorable OSR in their natal group.

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