Understanding mechanisms underlying foraging behavior of lady beetle larvae

Foraging behavior is a key component in the ability of predators to control prey populations. We investigated the role of aphid honeydew (excretion of feeding aphids), in the searching behavior of the native convergent lady beetle (Hippodamia convergens) larvae. Pea aphid (Acyrthosiphon pisum) is a high quality prey and bean aphid (Aphis fabae) is a low quality prey for the larvae. We conducted laboratory experiments to examine if the patch residence time of the larvae is influenced by honeydew of the two aphid species. We constructed an experimental arena with two patches. Each patch consisted of a stick and a petri dish lid at the base. In one of the patches the lid was covered with honeydew. We videotaped predator searching behavior and analyzed the effect of honeydew type and amount on the patch leaving behavior of the larvae. We found that the presence of both types of honeydew (A. pisum and A. fabae), significantly extended the patch residence time of the lady beetle larvae (bean aphid honeydew: p=0.00578; pea aphid honeydew: p=0.000516). We are planning to analyze the videotaped activity pattern (active/inactive time) of the larvae to examine if the duration of active search bouts is influenced by the type and the quantity of honeydew. If the larvae stay and search longer in a given patch, the probability of encountering plants containing aphid prey would increase. This in turn, would lead to enhanced prey encounter rates for the lady beetle larvae and better pest control.