Defensive functions of the trash-package of a green lacewing, Mallada desjardinsi (Neuroptera: Chrysopidae), against a ladybird, Harmonia axyridis (Coleoptera: Coccinellidae)

Abstract

To elucidate the defensive functions of the trash-package of the green lacewing Mallada desjardinsi larva against the ladybird Harmonia axyridis, the contact frequency, attack rate, and capture rate of ladybirds were compared between the 'with trash' or 'naked' treatments of the green lacewing. The contact frequency until the ladybird captured the green lacewing was significantly more in the 'with trash' treatment (median: four times) than in the 'naked' treatment (median: one time), which indicates that the trash-package of the green lacewing offers protection from predation by ladybirds. The attack rate of the ladybirds on the 'with trash' green lacewing larvae (55%) was significantly lower than that on the 'naked' ones (90%). After the ladybirds first attacked, their capture rate of the 'with trash' green lacewing larvae (18%) was significantly lower than that of the 'naked' ones (83%). Thus, the trash-package of the green lacewing affords prevention against recognition (primary defense) and subjugation (secondary defense) from the ladybird.