Predator-prey interactions among fish and larval amphibians: use of chemical cues to detect predatory fish

Abstract

Gravitational flow-through systems were used to determine whether larvae of two-lined salamanders, Eurycea bislineata, and Cope's grey treefrog, Hyla chrysoscelis, use chemical cues to detect predatory fish. Eurycea larvae were attracted to water conditioned with food, showed no response to water conditioned with green frog, Rana clamitans, tadpoles, and avoided water conditioned with a dangerous predator, the green sunfish, Lepomis cyanellus. Hyla tadpoles exposed to water conditioned with green sunfish spent significantly more time in refuges than did controls exposed only to water. In a comparable experiment performed at a natural breeding site, Hyla tadpoles significantly increased refuge use when exposed to water conditioned with fish. These data suggest that amphibian larvae use chemical cues in their natural habitats to minimize predation risk from fish.