Nutritional Benefits of Cannibalism for the Lady BeetleHarmonia axyridis(Coleoptera: Coccinellidae) When Prey Quality is Poor

Abstract

Abstract Cannibalism, a widespread phenomenon in nature, can both reduce competitors and introduce a high-quality food into the cannibal’s diet. We investigated the dietary benefits of cannibalism for larvae of the multicolored Asian lady beetle, Harmonia axyridis (Pallas). Cannibalism might benefit the larvae by allowing cannibals to take advantage of prey-detoxification already completed by the victim or the different, and perhaps more diverse, feeding history of the victim. In two laboratory experiments we reared H. axyridis larvae with aphid prey, and with or without conspecifics to consume, and recorded larval development and survivorship. In the first experiment, we fed groups of H. axyridis larvae an aphid species of intermediate quality, Aphis nerii (Boyer deFonscolombe), and prevented or permitted consumption of conspecifics of varied quality—conspecific victims had either fed upon the same intermediate quality food as the focal individual or had fed upon a high quality food. Cannibalism increase...