PREDATION RISK INCREASES WITH CLUTCH SIZE IN A COPEPOD

1. The relationship between clutch size and encounter time, escape behaviour and survival was studied by subjecting egg-carrying females of the copepod Eudiaptomus gracilis to fish predation in laboratory tanks. 2. Observation of the predation cycle of Zebra Fish showed time to prey encounter and prey survival time to be negatively correlated with clutch size. Prey with large clutches performed more evasive jumps when attacked but overall success in escaping was not related to clutch size. 3. In tanks with pure Eudiaptomus populations, both Zebra Fish and Roach fed selectively on individuals with large clutches. This demonstrates a clutch-size-dependent survival cost in a copepod. 4. The higher visibility of prey with large clutches, resulting in an increased encounter probability, is probably the cause of-their increased predation risk. The ability to escape after detection may also be influenced by prey visibility.