Description:
The Puerto Rican Coqui Frog (Eleutherodactylus coqui) is a nocturnal, invasive species that was introduced into Hawaii in the 1980s. Because they reach extremely high densities (up to 90,000 frogs/ha), they have the potential to affect invertebrate prey communities. Previously, researchers used frogs collected only at night to characterize their prey. Because Coquis use retreat sites near the forest floor during the day and understory perch sites at night, frogs collected at night might show different amounts and types of prey than would frogs collected in the morning. We analyzed stomach contents of 435 frogs collected in the morning (0300-0600 h) and at night (1900-2200 h) from five sites on the island of Hawaii. Frogs collected in the morning had 1.7 times more prey items and 2.1 times greater prey volume than those collected at night; however, prey composition did not differ between morning-and evening-collected frogs. Across sites, Formicidae (ants) and Amphipoda (amphipods) were the dominant prey, and at least 61.6% of their prey items were nonnative species. Across sites, morning- and evening-collected stomach contents were not different from environmental samples of leaflitter invertebrates but were different from environmental samples of foliage and flying invertebrates, suggesting that Coquis forage primarily in the leaf litter throughout the night. Previous research that investigated stomach contents of frogs collected only at night greatly underestimated the number and volume of prey items that Coquis consume during the entire foraging period but accurately described their primary prey: nonnative, leaf-litter invertebrates.