Predation upon Adalia bipunctata and Harmonia axyridis eggs by Chrysoperla carnea larvae and Orius laevigatus adults

Intra-guild predation (IGP) between sucking predators in relation to eggs of the exotic ladybird Harmonia axyridis (Pallas) and native Adalia bipunctata (L.) (Coleoptera Coccinellidae) was studied in laboratory. The green lacewing Chrysoperla carnea (Stephens) (Neuroptera Chrysopidae) and the pirate bug Orius laevigatus (Fieber) (Rhynchota Anthocoridae) may share the same niche as the two Coccinellidae species. Intra-guild predation may occur in glasshouses and crops when several predator species are used in integrated releases for the biocontrol of arthropod pests. In experimental arenas, the two sucking predators were individually offered the choice between eggs of the two ladybird species. Adult O. laevigatus reared on frozen Ephestia kuehniella Zeller eggs were not seen to feed on ladybird eggs, and immediately rejected this kind of food. Conversely, C. carnea larvae attacked the ladybird eggs without showing a preference for either species, although we observed that the A. bipunctata eggs were either completely eaten or more shrivelled than those of H. axyridis. In prey suitability experiments, C. carnea larvae that were allowed to develop by being fed an ad libitum supply of A. bipunctata eggs took longer to develop and had a lower survivorship compared to data (from literature) on E. kuehniella frozen eggs. H. axyridis eggs were not suitable for the larval development of C. carnea. We discuss the relevance of these results and intra-guild predation to the use of these species as biocontrol agents