A predator-prey game between bullheads and case-making caddis larvae

Abstract

A waiting game between predaceous bullheads, Cottus gobio L., and case-making caddis larvae, Halesus radiatus (Curtis 1834), was investigated in the laboratory. Bullheads killed 22 out of 155 larvae in their first attack. The remaining larvae feigned dead in their cases, and the bullheads waited for them to start moving again. The bullheads waited for shorter periods than did the caddis larvae. There was some overlap in the waiting time distributions since 32% of the caddis larvae waited for shorter times than the most persistent bullhead. The larval waiting time increased significantly with increasing attack intensity, and larvae that were exposed to simulated predator attacks (being pinched with forceps) feigned dead for less time when attacked once than when attacked three times. This indicates that larvae used information obtained during the attack for decisions about persistence time. The caddis larvae won most of the conflicts and were thus more successful than the bullheads in the waiting game described.