Interindividual variations in fruit preferences of the yellow-shouldered bat Sturnira lilium (Chiroptera: Phyllostomidae) in a cafeteria experiment

In studies on frugivory and seed dispersal, it is frequently assumed that individual frugivores of the same population behave as equivalents. However, there is growing evidence from dietary studies pointing out that, in many natural populations, individuals use different subsets of the total resource pool. As heterogeneity in foraging behavior and food selection may affect the outcome of the seed dispersal process, we tested whether yellow-shouldered bats Sturnira lilium (E. Geoffroy St.-Hilaire, 1810), the key neotropical seed dispersers, show interindividual variations in fruit preferences. Thirty individuals were submitted to cafeteria trials in a flight tent, when they were offered fruits of Solanum variabile Mart. (Solanaceae) Cecropia pachystachya Trec. (Urticaceae), and Piper aduncum L. (Piperaceae), which belong to the favorite genera consumed by S. lilium. Although S. variabile had the highest consumption rates on average, there were variations among individuals in the fruits consumed in the second and third places. These findings, together with interindividual differences in foraging areas observed in the same population, may be interpreted as preliminary evidence of individual specialization. As a possible consequence, frugivorous bats of the same population, despite being all legitimate dispersers, may differ in their efficiency.