SREL Reprint #2137





Reproduction under Predatory Threat: Trade-Offs between Nest Guarding and Predator Avoidance in Male Dollar Sunfish (Lepomis marginatus)


Male dollar sunfish exhibit parental care by building a nest and defending eggs and larvae against predators. I conducted field observations and experiments to determine whether intensity of nest defense was related to the presence of offspring and altered when males faced predatory threats to themselves. I measured intensity of nest defense as either time spent away from the nest when threatened with a predator or time spent guarding the nest both in the presence and absence of a predatory threat. Nest defense increased when eggs and larvae were present. When males were threatened with a model kingfisher (Ceryle alcyon) or a model heron (Ardea herodias), males returned more quickly to nests containing offspring than to nests that were empty. Predatory threat reduced the time spent guarding the nest and depressed activity level while on the nest. Habituation to models was not observed. Increased nest defense after spawning with and without the threat of predation indicates sensitivity to the value of offspring. However, reductions in nest defense in the presence of a predatory threat indicate that offspring survival is traded off against parental survival. Nest guarding in this species is an adaptive response that increases the chance of offspring survival while ensuring the survival and future success of the parents.

SREL Reprint #2137

Winkelman, D.L. 1996. Reproduction under predatory threat: tradeoffs between nest guarding and predator avoidance in male dollar sunfish (Lepomis marginatus). Copeia 4:845-851.

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