Individual variability in state-dependent feeding behaviour in three-spined sticklebacks.
We studied state-dependent feeding behaviour of three-spined sticklebacks, Gasterosteus aculeatus, during several trials of sequential encounters with 6-mm and 8-mm Asellus aquaticus prey. We used stomach fullness (the number of prey eaten previously) as an indicator for state, which we assumed to affect motivation for feeding. Dummy variable regression was used to study how the per trial energy consumption, the number of events experienced, feeding efficiency and the average time spent on each accepted prey depended on trial number, day and fish. A clear individual variability was found. Feeding behaviour was strongly related to the individual's recent feeding history (within a day). Logit regression models showed that the decision to accept or reject a prey encountered depended on the size of the fish as well as its state (stomach fullness). Although limited, our results demonstrate pronounced heterogeneity in feeding behaviour among individual fish. We discuss this phenomenon in the broader context of population regulatory mechanisms. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.
Salvanes
AgV
Department of Fisheries and Marine Biology, University of Bergen
Hart
PJB