Dietary analysis of three migratory bats in eastern Pennsylvania

This article compares the stomach contents of 16 eastern red, 18 hoary, and 11 silver-haired bats from eastern Pennsylvania. Eastern red bats contained six insect orders (Coleoptera, Diptera, Hemiptera, Lepidoptera, Neuroptera, and Trichoptera), with lepidopterans as 82.01% of average percentage volume. Hoary bats contained three insect orders (Coleoptera, Lepidoptera, and Neuroptera), with lepidopterans as 88.14% of average percentage volume. Silver-haired bats contained eight insect orders (Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, Neuroptera, Plecoptera, and Trichoptera), with dipterans as 46.89% of average percentage volume. Silver-haired bats showed the greatest dietary breadth (Levins’s Bˆ = 3.13), and eastern red and hoary bats showed the greatest dietary overlap (Schoener’s D = 0.916). A nonparametric multivariate analysis found that silver-haired bats were significantly different (p < .001) from both eastern red and hoary bats, but eastern red bats were not significantly different from hoary bats, and there was no significant difference between male and female eastern red (p = .858) or hoary bats (p = .369).