Spatial and Temporal Variation in the Diet of the Eastern Red Bat in Kentucky

Abstract

Eastern red bats (Lasiurus borealis) are nocturnal insectivores distributed throughout eastern North America. While the dietary composition of this species has been broadly studied, dietary variation in Kentucky is not well documented. To evaluate potential regional, seasonal, and reproductive dietary variation for this species, we analyzed fecal samples from 121 individual bats collected throughout Kentucky from June 2004 to September 2006. Fecal samples were dissected under magnification, and prey in fecal samples were visually-identified to ordinal level. Results of our study suggest that overall, beetles (Coleoptera) and moths (Lepidoptera) were consumed about equally. Beetles comprised most of the diet in spring and summer with a shift to moths as the main prey item in autumn. Beetles were consumed more in the Mississippi Valley Loess Plains and Southwestern Appalachian ecoregions, whereas moths were consumed more in the Central Appalachian and Interior Plateau ecoregions. These data suggest variation in the eastern red bat diet throughout Kentucky, which we attribute to climatic and regional environmental factors. We speculate that eastern red bats may favor moths in autumn to build essential energy reserves in preparation for hibernation.