Foraging behavior of a freshwater copepod: Frequency changes in looping behavior at high and low prey densities.

The foraging behavior of Mesocyclops edax in artificial patches of high and low prey density was examined. In low density patches Mesocyclops swam in an irregular curvilinear path with little or no looping behavior. In high density patches Mesocyclops exhibited extensive horizontal and vertical looping behavior. Horizontal loops were performed in the normal hop and sink swimming mode, while vertical loops were associated with predator attacks on single prey items. Previous studies on terrestrial invertebrates revealed similar looping behaviors by predatiors and have suggested such looping behavior will increase the time a predator will spend in high versus low density prey patches. When food is patchily distributed and consumers are food-limited, the adaptive significance of remaining in a high density food patch may be substantial.