Cost of exposure to trematode cercariae and learned recognition and avoidance of parasitism risk by fathead minnows Pimephales promelas
Abstract:Fathead minnows Pimephales promelas exposed to cercariae of the trematode Ornithodiplostomum sp. incurred a significant mass loss 17 days after exposure to 20 or 120 cercariae. Parasite-naïve P. promelas showed no evidence of innate recognition or avoidance of cercariae. After a single exposure to cercariae, however, fish responded to chemical and visual cues of dead (thawed) cercariae with a reduction in activity. Encounter rate with cercariae, and hence infection rate, increased with fish activity. The data indicated that experienced P. promelas associated parasitism risk with novel chemical and visual cues that later triggered avoidance behaviour. Parallels and interactions between antiparasite behaviour and antipredator behaviour open new avenues for behavioural ecological research in risk-sensitive decision-making.
Document Type: Regular Paper
Affiliations: 1: Biosciences Department, Minnesota State University Moorhead, 1104 7th Avenue South, Moorhead, MN 56560, U.S.A 2: Department of Biological Sciences, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 Canada
Publication date: 2008-12-01