Does social feeding mitigate larval starvation in two spotted lady beetles (Adalia bipunctata)?

Lady beetles are insect predators that typically lay eggs in clusters, which may provide benefits for clutch mates. One potential advantage to larvae emerging as a group is that if one captures a prey item, others can share in the meal, because larvae are attracted to chemicals that are released by damaged prey. While a shared meal likely reduces the per capita food intake of a hatchling, it may also provide enough nutrition to prevent an early death by starvation during an especially vulnerable stage. We manipulated densities of two-spotted lady beetle (Adalia bipunctata) hatchlings in various experimental assays to test whether the presence of clutch mates increases probability of capturing prey and the survival of individual hatchlings. In the small arenas with varying densities of larvae and one prey item, lady beetle foraging efficiency increased as the initial density increased. However, initial larvae density did not affect survival. In various on-plant trials that focused on combinations of prey and larvae densities, increasing the initial density of lady beetle larvae did not improve the survival of the larvae. Therefore, while having more hatchlings on a plant improved their collective ability to capture prey, it did not translate into an improvement in lady beetle survival. Understanding the influences on survival of two-spotted lady beetles during their hatchling stage may enhance their use in biological control.