Seasonal isotopic niche of a rodent: High between-individual variation but no changes in individual niche width during the rich-resource period

The dynamics of trophic niche width in animals at both population- and individual-level is potentially influenced by temporal variation of food resources, by between-individual differences in food-resource rank preferences, and also by competition. Using stable isotope of carbon and nitrogen (δ13C and δ15N) of fecal samples, we investigated the trophic niche dynamics and individual variation in food-resource use by the arboreal rat Rhipidomys macrurus, in the highly seasonal Brazilian savanna (Cerrado). We tested the hypothesis that dietary niche expansion during the rich-resource period (wet season) occurs via individual specialization and consequently lower individual niche overlap in contrast with niche retraction during the low-resource period (dry season) via increase in niche overlap and expansion of individual niches. The results indicated that R. macrurus is primarily frugivorous and presents a wider isotopic niche in the rich-resource period in comparison to the low-resource pe...