Meeting Abstract

P1.26  Friday, Jan. 4  Testing the temporal consistency of dietary individual specialization in Rufous collared-sparrows from different ecological environments: the role of environmental variability MALDONADO, K.*; LÓPEZ-MORGADO, N.; PÍRIZ, G.; ANGUITA, S.; REYES, C.; CHAURA, R.; SABAT, P.; UNIVERSIDAD DE CHILE, SANTIAGO, CHILE; UNIVERSIDAD DE LA SERENA, LA SERENA, CHILE; UNIVERSIDAD DE CHILE, SANTIAGO, CHILE; UNIVERSIDAD DE CHILE, SANTIAGO, CHILE; UNIVERSIDAD DE CHILE, SANTIAGO, CHILE; UNIVERSIDAD AUSTRAL DE CHILE, VALDIVIA, CHILE; UNIVERSIDAD DE CHILE, SANTIAGO, CHILE kmaldonado@ificc.cl

There is increasing evidence that ecological generalist populations, which use a wide diversity of resources, are in fact the sum of specialized individuals. This phenomenon, called individual specialization (IE), promotes frequency-dependent interactions, which may drive evolutionary diversification, and influence population dynamics and ecological interactions. Nevertheless, despite the temporal consistency of IE is crucial to understand these ecological and evolutionary consequences, further research on this topic is clearly required. We investigated the timescales at which dietary IE occurs in bird populations (Zonotrichia capensis) that experience different levels of environmental variability –from Desert, Mediterranean and cold-temperate climates. In order to determine the birds’ diet at different times, we used stable isotope signatures (δ¹⁵N) from tissues characterized by different turnover rates. We found differences in the level of IE among populations; individuals from the cold-temperate site, in contrast to birds from the Mediterranean site, showed a high temporal consistency in their dietary habits. Interestingly, dietary IE did not appear to be maintained over long-term timescales. We suggest that these individual dietary shifts are influenced by seasonal changes in food diversity and intraspecific competition. Funded by Fondecyt 3120229 to K.M and Fondecyt 1120276 to P.S.