Sources of variability in the transition from extensive to intensive search in coccinellid predators (Homoptera: Coccinellidae)

In an environment structured by habitats, prey patches, and prey, predators such as coccinellids have two movement modes. The extensive search and the intensive search which results from prey capture are adopted for patch localization and exploration, respectively. The variability of changes from extensive search to intensive search was studied in larvae of the aphidophagous coccinellidSemiadalia undecimpunctata to find out their possibility of adaptation to a fluctuating environment. The temporal organization of coccinellid movements appears far more complicated than the generally accepted succession of extensive search, feeding, and intensive search. Their paths are characterized by the presence of time intervals devoted to intensive search before feeding, a highly variable path response after prey consumption (larvae may adopt intensive search immediately, later, or never), and the alternation of time periods devoted to either extensive search or intensive search after prey ingestion. This interindividual variability suggests that coccinellids have the ability to adapt to heterogeneity or short-term changes in environmental conditions, particularly in prey distribution. These results are in favor of the use of these predators in biological control programs.