Food selection and feeding patterns in nectarivorous bats: <i>Leptonycteris yerbabuenae</i> and <i>Glossophaga soricina</i>

Sympatric species reduce competition for resources due to differences in one or more of their niche dimensions. Biotic interactions between pollinators and variations in the availability and quality of resources are important factors that determine food selection in bats. The nectarivorous species <i>Leptonycteris yerbabuenae</i> and <i>Glossophaga soricina</i> coexist temporarily in much of their distribution and depend on nectar to feed. These species have similar requirements but differ in the way they obtain food. The coexistence of bat species with similar requirements, such as <i>L. yerbabuenae</i> and <i>G. soricina</i>, suggests that these species have strategies for avoiding competition and maximizing their nectar consumption. However, it is unclear how these bat species select resources and adjust their visits to the available floral resources. We therefore analyzed nectar selection and feeding patterns in these two bat species under captive conditions. We conducted experiments in which we controlled resource type and its availability by offering the bats different artificial nectar solutions, while we removed interspecific interactions. These solutions differed in concentration and sugar type, and some were similar to the nectar offered by chiropterophilic plant species. The bat species presented differences in food selection; <i>G. soricina</i> fed mainly on resources similar to <i>Ipomoea</i> and sucrose sugar. In contrast, <i>L. yerbabuenae</i> preferred those resources similar to the nectar of <i>Acanthocereus</i> cacti. In addition, the timing of feeding for each solution also differed. These results suggest low levels of competition between species under abundant resources and low density of individuals; however, such conditions are not always found in nature, and patterns may change with increased food scarcity and a high density of competitors.