1:45 PM - 3:15 PM
[HTT15-P07] Stable isotope dietary analysis of wild groups of Japanese macaques
Keywords:stable isotope, feeding habit, Japanese macaque
The Koshima group of Japanese macaques is a population in which all individuals have been identified and social attributes such as age and hierarchy have been recorded. In this study, we conducted a dietary analysis at the individual and group level on this group and aimed to quantitatively indicate the influence of these social attributes on feeding habits.
We used carbon, nitrogen, and sulfur stable isotope ratio analysis, and the individuals analyzed were 38 individuals, including those belonging to two groups, the Main group and the Maki group in the Koshima population, and solitary individuals. As a result of the analysis, the Koshima population has large variations compared to other groups in all three stable isotope ratios. In particular, clear differences were also shown between groups as well as between individuals with regard to sulfur isotope ratios.
We then classified the food resources consumed by this population into three main categories, forest-, marine-, and provisioning (human)- derived food resources, and analyzed the variation in the isotope ratios of the macaques using the MixSIAR isotope mixing model. As a result, it became clear that these variations are influenced by the sex and group affiliation of each individual. Specifically, there was a clear male-female difference in preference for marine-derived food resources, with male individuals in both groups showing greater preference than female individuals, while female individuals showed a greater preference for human-derived food resources than male individuals.
Furthermore, marine-derived food resources, which have not been regarded as important food resources, accounted for 10-20% of the food consumed by all individuals, indicating the peculiar nature of the Koshima group's diet.
We used carbon, nitrogen, and sulfur stable isotope ratio analysis, and the individuals analyzed were 38 individuals, including those belonging to two groups, the Main group and the Maki group in the Koshima population, and solitary individuals. As a result of the analysis, the Koshima population has large variations compared to other groups in all three stable isotope ratios. In particular, clear differences were also shown between groups as well as between individuals with regard to sulfur isotope ratios.
We then classified the food resources consumed by this population into three main categories, forest-, marine-, and provisioning (human)- derived food resources, and analyzed the variation in the isotope ratios of the macaques using the MixSIAR isotope mixing model. As a result, it became clear that these variations are influenced by the sex and group affiliation of each individual. Specifically, there was a clear male-female difference in preference for marine-derived food resources, with male individuals in both groups showing greater preference than female individuals, while female individuals showed a greater preference for human-derived food resources than male individuals.
Furthermore, marine-derived food resources, which have not been regarded as important food resources, accounted for 10-20% of the food consumed by all individuals, indicating the peculiar nature of the Koshima group's diet.