Habitat Use by Aerial Insectivorous Bats of External Areas of Barro Colorado Nature Monument, Panama

Abstract

Aerial insectivorous bats comprises almost half of the community of neotropical species. They contribute to pests control and herbivory reduction and they do it mostly by using echolocation (active or passive) to find their prey. Through acoustic sampling we assessed the structure of aerial insectivorous bats in four microhabitats (upper and lower forest edge, and upper and lower open space) in external areas of Barro Colorado Nature Monument. Seven sites were chosen for sampling, each was visited four times, and bat recordings were made for up to four consecutive hours. We found differences in the structure of the communities foraging in the microhabitats, and a tendency of certain species to be associated with certain microhabitats. Species with preference for the forest edge (e.g. Saccopteryx bilineata )showed sharper echolocation calls of short duration, short pulse intervals, and a combination of components of FM (frequency modulation) and QCF (quasi-constant frequency). Species that showed a preference for open space (e.g. Noctilio leporinus ) have echolocation calls with lower frequency, long duration, long pulse intervals and QCF components combined with FM. Differences between both cases are due to the foraging strategy, where some bats prefer the upper and other the lower parts of the space. This result provides important information to the knowledge of resource partitioning in aerial insectivorous bat communities, as well as on the importance of having a standard protocol to improve the use of acoustic monitoring.