We investigated the relatedness among adult females in wild Rhesus macaque (Macaca Mulatta) to understand what kinship affects social behavior. DNA were extracted from fecal samples and microsatellite markers were used for establishing kinship network. Totally 117 specimens of 38 individuals were used to perform molecular experiment, each individual was collected more than 2 specimens, each specimen was amplified over than 3 times. 6 high polymorphic microsatellite loci of 10 candidate loci were selected successfully. On average, the PIC value (Polymorphism information content) of microsatellite loci was 0.567, ranging from 0.467 to 0.744. Establishing kinship network and comparing it with affiliative behavior network, we found that significant correlation between kinship network and affiliative behavior network, which supported to kin selection theory. Supporting by hierarchy data, genetic similarity is useful to determine the pedigrees and to explain social behavior.
Limestone hills are an unusual habitat for primates, prompting them to evolve specific behavioral adaptations to the component karst habitat. From September 2012 to August 2013, we collected data on the diet of one group of Assamese macaques living in limestone forests at Nonggang National Nature Reserve, Guangxi Province, China, using instantaneous scan sampling. Assamese macaques were primarily folivorous, young leaves accounting for 75.5% and fruit accounted for only 20.1%. The young leaves of Bonia saxatilis, a shrubby, karstendemic bamboo that is superabundant in limestone hills, comprised the bulk of the average monthly diet. Moreover, macaques consumed significantly more bamboo leaves during the season when the availability of fruit declined, suggesting that bamboo leaves are an important fallback food for Assamese macaques in limestone forests. In addition, diet composition varied seasonally. The monkeys consumed significantly more fruit and fewer young leaves in the fruit - rich season than in the fruit - lean season. Fruit consumption was positively correlated with fruit availability, indicating that fruit is a preferred food for Assamese macaques. Of seventy - eight food species, only nine contributed >0.5% of the annual diet, and together these nine foods accounted for 90.7% of the annual diet. Our results suggest that bamboo consumption represents a key factor in the Assamese macaque's dietary adaptation to limestone habitat.
To what extent do primates - our closest phylogenetic relatives and thus the most relevant to understanding the origins of human hygiene practices - exhibit counterstrategies when faced with risk of infection? To address this, we conducted feeding-related infection-avoidance experiments with 5 species of Papionini and Hominini: Macaca fuscata fuscata, Macaca fascicularis, Mandrillus sphinx, Pan troglodytes troglodytes, and Pan paniscus. First, we found that free ranging Japanese macaques vary in their sensitivity to infection risk during foraging under both experimental and natural conditions, and the ‘hygienic tendencies’ of individuals were good predictors of their current levels of geohelminth infection. Then, we expanded our experimental protocol to include visual, olfactory and tactile cues of feces and other contaminants such as blood, semen, rotten meat and rotten fruit with captive chimpanzees, semi-free-ranging mandrills, group-housed long-tailed macaques and semi-free-ranging bonobos. Results indicate that subjects demonstrated risk-sensitivity to these potential contaminants, manifest as increased latencies to consumption of food rewards, maintenance of greater distances from contaminants, and/or outright refusals to consume food in test versus control conditions. Current work is testing whether risk-averse individuals with greater tendencies to avoid potential sources of contamination are less prone to infection and thus characterized by better general health than risk-prone individuals. These studies are aimed at better understanding behavioral immunity to infection among primates, which is fundamental to the understanding of the origins of human hygiene.
Castration has been used in nonhuman primates to control population demography, but the impact of this procedure on the social relationships of male Japanese macaques living in a complex society has not yet been investigated. This research examined fecal glucocorticoids (fGC) and fecal testosterone (fT) concentrations in male Japanese macaques residing in two social groups of contrasting environments (Jigokudani, Japan and Born Free Primate Sanctuary - BFS, Texas, USA), and males housed individually. The primary goal was to test the effect of castration on dominance hierarchy and steroid concentrations in Japanese macaques. We also investigated social, environmental and biological factors affecting steroid hormones. We collected behavioral data (focal animal and ad libitum sampling) to establish male dominance rank in the social groups, and fecal samples during the non-mating season from all males. We found that males housed in single cages had fT concentrations similar to castrated males and lower than intact social males. Castrated males maintained a dominance hierarchy primarily determined by age, and they were less aggressive than intact social males. Age had a positive relationship with fGC, but the opposite trend on fT levels. Rank and temperature were directly correlated to fT concentrations only in the intact social group. Our findings indicate that testosterone can be a consequence of the social structure of the group, and therefore is significantly affected by the social environment. Our results can contribute to the management and monitoring of primate populations in the wild and in captivity because they reveal that a complexity of connections link the social environment with male Japanese macaque steroid concentrations.
Food transfer is defined as the unresisted transfer of food from one food-motivated individual, the “possessor”, to another, the “recipient” (Feistner & McGrew 1989). This behavior has been described in different terms, including sharing, scrounging, and tolerbated theft, and it is usually accompanied by diverse behaviors such as begging, displacement of feeding spot, resistance of possessor, stealing, offering, and retrieving (Yamagiwa et al., 2015). Food transfer is mainly reported from apes, however, very few from genus macaca. Here we preliminary report food transfer behavior observed in stump-tailed macaques (Macaca arctoides) in Khao Krapuk Khao Taomor Non Hunting Area, Thailand. In this report, “Retrieving” - an individual takes food that another individual has dropped on the ground or placed there - is regarded as food transfer (see Yamagiwa et al., 2015). The aspect of transfer is different by the food item; transfer was more frequently occurred when they are eating food item that is not abundant and rare, or need to pay risk to obtain. Food transfer is often observed when monkeys are eating big food items which produce the food particles during eating. On the other hand, small food items or all-eatable food items are rarely transferred. Plant food transfer was observed not only among adults but also from adult to immature including transfer from mother to infant. Social interaction which can be interpreted as “Begging behavior” like presenting and greeting was also observed before food transfer occurred.
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