Egg Load as a Major Source of Variability in Insect Foraging and Oviposition Behavior

Foraging and oviposition behavior of insects directly influences offspring production and fitness, and is therefore particularly amenable to analysis with optimization models. These models have identified two general constraints on female fitness: host availability and egg complement. Research on insect oviposition has thus far focused on external, environmentally-derived cues such as host density and quality. Here we review recent studies and suggest that insects adjust their foraging and oviposition behavior in response to their perceived risk of becoming egg limited. Females with higher egg loads (1) search more intensively, and therefore encounter more hosts per foraging bout, (2) accept for oviposition hosts of lower rank in a preference hierarchy, (3) spend less time handling hosts, and (4), for gregarious species, deposit larger clutches. Given the different constraints for a forager with a changing egg load, we hypothesize that an individual female may shift between maximizing the number of hosts encountered to optimizing the quality of hosts selected for oviposition. Incorporating egg load dynamics into foraging models and empirical studies will enhance our understanding of insect oviposition behavior.