Behavioral repeatability and foraging performance in wild free-flying nectarivorous bats (Glossophaga commissarisi)

Abstract

Animal individuals show patterns of behavior that are stable within individuals but different among individuals. Such individual differences are potentially associated with differences in foraging efficiency and in fitness. Furthermore, behavioral responses may be correlated in specific suites of so called behavioral syndromes that are consistent across different contexts and with time. Here we present a field investigation on individual differences between wild, free-flying nectarivorous bats (Glossophaga commissarisi) in the foraging context. We further investigated how individual differences effect foraging performance, and we examined their interdependence within hypothesized behavioral syndrome structures. Free-ranging bats were individually identified as they visited an array of 24 artificial flowers with nectar of high or low sugar concentration. We found that three behavioral measures of foraging behavior were individually stable over the two-month observation period. We investigated the link between individual behavioral measures and measures of foraging performance using generalized linear mixed models. Individual measures of foraging performance showed significant repeatability, and we found evidence that bats making more visits per bout tend to be slower in learning to avoid unprofitable flowers. We used a multi-response generalized linear mixed model to estimate between-individual correlations and compare hypothesized syndrome structures. There were no clear patterns of between-individual correlations among the behavioral measures in our study, despite the measures exhibiting significant repeatability. This may indicate that foraging performance depends on multiple individual behavior dimensions that are not adequately described by simple models of behavior syndromes.