Diet and reproduction of sympatric nectar-feeding bat species (Chiroptera: Phyllostomidae) in French Guiana

Abstract

This dissertation examines the ecology of nectar-feeding bats (Phyllostomidae: Glossophaginae) and the plants that rely on them for pollination. The major findings, based on a thorough review of the literature and field studies in French Guiana, are that (1) 360 plant species from 44 families in the New World and 168 plant species from 41 families from the Old World have been reported to rely on bats for pollination; (2) during a two-year study, three sympatric glossophagine species in a lowland site in central French Guiana visited a total of 14 plant species, 6 of which had not previously been reported in the diets of bats, for nectar/pollen; (3) 10 of 14 plant species were visited by both of the two most common glossophagine species (Anoura geoffroyi and Lionycteris spurrelli ) at the site, but the proportions in which they were found in the bats' diets varied significantly to the point that a canonical discriminant analysis and logistic regression analysis showed that A. geoffroyi and L. spurrelli had distinct diets; (4) these differences may be attributed to a lack of fit between the flower and visiting bat or to flower constancy and differences in foraging behavior; (5) A. geoffroyi and L. spurrelli differed in their responses to seasonal changes in resources with individuals of L. spurrelli visiting significantly more plant species each night in the dry than in the wet season, while those of A. geoffroyi did not show any variation between seasons; (6) the three glossophagine species at the study site fed on insects year-round; (7) females of A. geoffroyi and L. spurrelli gave birth to one pup per year in the dry season, though the population of A. geoffroyi appeared to have a more synchronized birthing period; (8) lactating females of A. geoffroyi were twice as likely to be captured carrying their young than those of L. spurrelli; and (9) the levels of morphological specialization and functional contribution were not found to be correlated in 23 glossophagine bats suggesting that both must be used when developing conservation priorities. This study improves our understanding of how sympatric glossophagine species partition their shared resources and sheds light on the feeding and reproductive habits of poorly known species, such as Lionycteris spurrelli, that are necessary for assessing threats and developing conservation plans.