Abstract

We investigated the presence of chemical alarm signals in juvenile Green Sunfish (Lepomis cyanellus) under laboratory conditions. We exposed individual sunfish to skin extracts of conspecifics and swordtails (Xiphophorus helleri), a species not known to possess alarm pheromones and that is phylogenetically distant and allopatric from green sunfish. Sunfish significantly increased time spent freezing and time with dorsal fin rays erect (known antipredator postures) in response to conspecific skin extract but not to swordtail skin extract. No significant difference was noted in change in area use for sunfish exposed to conspecific versus swordtail skin extract. These results suggest that juvenile green sunfish possess chemical alarm signals. This is the first such demonstration in a centrarchid species.