Life history fitness of giant ladybird predator (Coleoptera: Coccinellidae) of woolly aphids (Hemiptera: Aphididae) in varying prey densities from northeast India

摘要

Quantity of natural prey available to insect predators varies in time and space and it influences the fitness of individual predators. This was examined for Anisolemnia dilatata (Fab.) which is a specialist predator of woolly aphids of bamboo plants and sugarcanes, and endemic to south Asia and Asia-Pacific regions. Results of a laboratory study using 45 larvae and 10 adult females showed that individual A. dilatata larvae performed best at an optimal density of 250 live aphids per larva per day, and adult females from these larvae matured faster and produced higher number of viable eggs than the larvae that grew and developed at sub-optimal prey density of 200 or less aphids. About 73-80% of the larvae that survived at the density of 50 or 100 or 150 aphids per day took significantly longer time to complete development and to reach the age at maturity. Such females were significantly smaller in size and produced fewer viable eggs. Results showed that larvae and adults of A. dilatata required high density of aphid prey to support its optimal life history fitness. Results hold promise in the application of this predator in the control of waxy aphid pest of cultivated bamboos and sugarcanes.