MORPHOLOGICAL CHARACTERISTICS PREDICT ALTERNATE FORAGING STRATEGY AND MICROHABITAT SELECTION IN THE ORANGE-BELLIED BAT, LAMPRONYCTERIS BRACHYOTIS

Abstract

Neotropical bat species may coexist because they forage in different places or in different ways. The small insectivorous orange-bellied bat, Lampronycteris brachyotis (Phyllostomidae), differs from coexisting gleaners in key ecomorphological characteristics, including longer, narrower wings and smaller ears. Using telemetry, we measured range size, range use, and activity patterns, and assessed habitat preferences for 9 individuals for 50 nights over 4 months on Barro Colorado Island, Panama. The bats spent the night in individual, medium-sized (22–27 ha) foraging areas within forested regions close to shorelines, up to 4 km away from the day roost. Each bat spent most of its time in a small (3–5 ha) core area. Foraging flights ranged from a few s to more than 70 min. Total flight time per night averaged 3.5 h and flight distance was estimated to be 60 km. There were no distinct activity peaks. Our tracking data suggest that L. brachyotis primarily forages in the canopy, where it gleans insects from vegetation in a combination of perch hunting and continuous flight. This species may also catch insects in air above the canopy. This unique behavior among gleaning insectivorous phyllostomids corroborates our hypothesis that morphological adaptations combined with behavioral flexibility reflect distinct differences in foraging strategies and microhabitat selection. We conclude that differential use of space and hunting strategies promotes coexistence among the species-rich guild of Neotropical insectivorous gleaning bats.