Resource dynamics and fitness strategy: Anisolemnia dilatata's (Coleoptera: Coccinellidae) response to clumped woolly aphid patches on bamboo.

Unlike majority of generalist predators of soft-body phytophagous insects, the giant ladybeetle predator, Anisolemnia dilatata (Fabricius), is a specialist predator of woolly aphids of bamboo plants in parts of tropical Asia. This predator has a long development time and reproductive duration. This study investigated through a field-cum-laboratory approach how a predator optimizes its reproductive and generational timing in bamboo habitats with patchy resources of woolly aphids. Results revealed that the giant ladybeetle females produced 69.20% of total eggs in the high prey density phase (mean ± SEM: 52.52 ± 9.65 aphids/leaf), comprising an average of 11 weeks out of the prey population cycle of 38 weeks. However, gravid females initiated egg-laying at a minimum average prey density of 16.35 aphids/leaf. Females chose narrow and thin parts of bamboo plants for depositing egg batches at a minimum distance of 21.05 cm and a maximum of 46.95 cm from the nearest aphid colony. Such behaviour is unique in aphidophagous predators directed at avoiding egg predation from actively growing conspecific or heterospecific larvae that continue to feed aphids after cessation of egg-laying in the declining phase of the population when prey resources become scarce. [ABSTRACT FROM AUTHOR]