Article

Download article 		Title: Between-individual variation drives the seasonal dynamics in the trophic niche of a Neotropical marsupial
Author: Pires, M. M.; Martins, E. G.; Araújo, M. S.; Reis, S. F.
Year: 2013
Is part of: Austral Ecology (Print), v. 38, p. 664 - 671
DOI: https://doi.org/10.1111/aec.12011

Citation: Pires, M. M.; Martins, E. G.; Araújo, M. S.; Reis, S. F.; Between-individual variation drives the seasonal dynamics in the trophic niche of a Neotropical marsupial. Austral Ecology (Print), v.38, p. 664-671, 2013

Abstract: The dynamics of population niches result from the variation in resource use within individuals and also from the variation between individuals. The prevalence of one mechanism or the other leads to competing hypotheses about the major mechanisms underlying the empirical observations of the contraction/expansion dynamics of the trophic niche in natural populations. In this study, we investigated how within- and between-individual variation in resource use shapes the food niche dynamics of the woolly mouse opossum, Marmosa paraguayana (Didelphimorphia: Didelphidae), in a remnant of the highly seasonal Cerrado in south-eastern Brazil. To do so, we analysed the faecal samples of live-trapped individuals to determine their diets within the wet and dry seasons. In addition to a seasonal shift in the composition of the diet, the population trophic niche was significantly wider during the dry season than the wet season. This expansion resulted from larger between-individual variation in the dry season that was not related to sex preferences, whereas the individual niche widths did not significantly increase from the wet to the dry seasons. Our findings add to the growing list of animal populations that show individual-level variation in resource use. Furthermore, these results represent a pattern of individual-level response to seasonal changes that is different from patterns reported for other organisms. We suggest that a pathway to build more realistic foraging models and produce more accurate predictions on population and community dynamics is to consider between-individual variation and short-term niche dynamics.



Funding: We are very grateful to J. D. G. Neto and M. M. Pinto of Mogi Guacu Biological Reserve for logistical support. M. M. Pires was supported by a Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) scholarship; M. S. Araujo was supported by the CAPES (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior) and NSF (National Science Foundation). S. F. dos Reis was partially supported by a research fellowship from CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico). This research was supported by grants from FAPESP (Brazil). 		Financed by: