Habitat Quality and the Foraging Behaviour of Coccinellid Larvae

Abstract

SUMMARY (1) The aim of this study was to determine whether an invertebrate predator with limited sensory abilities could modify its foraging behaviour in response to changes in habitat quality, and so maximize its feeding rate. (2) The effects of hunger, rate of prey encounter and rate of food intake on the foraging behaviour of fourth instar Coccinella septempunctata L. larvae were investigated. (3) The duration of area-restricted searching behaviour following prey encounter increased with increasing hunger. This increased the probability of encountering a subsequent prey item and ultimately the time spent in a patch and the degree to which each patch was exploited. (4) Handling time increased as hunger increased. (5) Changes in the duration of the area-restricted searching behaviour and handling time were dependent on hunger level and not average encounter rate or average rate of food intake. (6) Extensive searching behaviour did not change with hunger level. (7) Hunger-induced changes in foraging behaviour enabled larvae to forage in a manner consistent with optimal foraging theory.