Limb Regeneration and Interference Competition Consequences on Foraging Efficiency of Coccinella undecimpunctata and Hippodamia variegata

Regeneration of limbs lost during development has been recorded in a large number of species of hexapoda including many Coccinellids. Although regeneration has obvious survival and fitness benefits, it has also been demonstrated to impose costs on development, reproduction, and behavior. To investigate consequences of regeneration on foraging behavior, Coccinella undecimpunctata L. and Hippodamia variegata (Goeze) larvae were treated to remove one limb, allowed to pupate and regenerate and then prey searching ability assessed. Different densities of adults were placed in Petri dishes with aphid prey and consumption assessed over a 24-h period. Amputation/regeneration, predator species, and predator density significantly affected the total number of aphids consumed. Aphid consumption rates and predation efficiency of both regenerated and control beetles significantly increased as predator density increased. Although there were significant differences in consumption between ablated/regenerated and control C. undecimpunctata at each predator densities, H. variegata did not. Further, mutual interference was significantly higher for regenerated compared with control C. undecimpunctata but not so for H. variegata. This is the first demonstration of an effect of ablation/regeneration on foraging behavior of C. undecimpunctata and suggests that H. variegata demonstrates an adaptive phenotypic response to limb regeneration. Coccinellids are widely used as biological agents and these findings concerning the impact of variation in predator density have clear implications for the management of predator-prey ratios in order to maximize efficiency of pest consumption. Key words: ablation, amputation, biocontrol, consumption, predation efficiency