Oviposition Mistakes in Herbivorous Insects: Confusion or a Step Towards a New Host Plant?

Abstract

Insects sometimes lay eggs on host plants unsuitable for their offspring. One explanation for this behavior has been that the association of insect and plant is new, and therefore, the insect has not had time to develop a capacity for discrimination. We explore an alternative explanation using a simulation model of gall-forming cecidomyiid oviposition behavior. It is demonstrated that insects which can discriminate between plant types have little advantage over «confused» (non-discriminating) counterparts when the proportion of poor host plants is large and the time available for oviposition is short. When non-discriminating females also oviposit on their eclosion plant the advantage of discrimination is negligible. We suggest that for insects where a host shift is costly, e.g. gall-forming cecidomyiids with an intimate relationship with the plant, there are only small penalties to retaining a non-discriminating oviposition strategy. Insect traits such as short adult life span and poor capacity for directed flight further act to maintain the insect in a state of perpetual «confusion»