Dados do Trabalho

TÍTULO

GLUTTONY THEORY: DO LARGER BATS EAT MORE PLANT SPECIES?

Resumo

Neotropical bats play important ecological functions in their ecosystems, one of them being the seed dispersal of plants from pioneer and intermediate successional stages, making bats important elements in plant reproduction and forest regeneration. As recent studies focusing on functional traits have reported relationships between species characteristics and ecological functions, in this study we tested if larger bats feed on a greater number of plant species, having thus a greater contribution to forest recovery. Our hypothesis is that because of their higher energetic demand, larger bats feed on a larger set of plant species. To answer this question, we captured bats in three municipalities in the region of the Mantiqueira chain, São Paulo state, Brazil, and collected their body mass and feces. Body mass was estimated using a dynamometer. Each bat individual remained for 30 minutes in a cotton bag to defecate, and the feces collected were preserved in alcohol 70%. In the laboratory, seeds were identified with the support of a magnifying glass, specialized literature and available data bank of seed species of the area. We run a linear model to evaluate the relationship between the mean body mass of the bat species and the number of plant species consumed. We only considered the bat species with a minimum of N=5 individuals. We found a total of 21 plant species consumed by seven bat species. Although there is a tendency of larger bats feed on a greater number of plant species (β=0.08) no significant relationship was found for these variables (p= 0.32). Our results suggest that although having higher energetic demand due to flight and the size per se, larger bats do not necessarily eat more plant species than small ones, and approximately 80% of the variability of our data was not explained by this functional trait (R²= 0.19). One possible explanation to our results is that larger bats have dietary preferences to plant species that provide higher energetic rewards, or that each bat species has dietary preferences based on easily of access, fruit size or plant palatability. Our results show that small and large bats have a similar contribution to potential forest regeneration in terms of the number of plant species dispersed. However, if bats really have dietary preferences and each bat species feed on a different group of plants, the conservation of a greater number of bat species is desired to maintain the seed dispersal function to the greater number of plant species as possible.

Palavras-chave

Bats, functional traits, body mass, seed dispersal.

Financiamento

This study was partially financed by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).