Single experience learning of host fruit selection by lepidopteran larvae.

Neonate larvae of a lepidopteran, the codling moth (Cydia pomonella L.) search for their host fruit after hatch. The process of host searching is known to be activated by kairomones contained in host fruit volatiles, but the mechanism of actual selection and infestation of the fruit is unclear. Here we show that lepidopteran neonates can utilize single experience learning in selection and infestation of host apple. We found that the process of host fruit selection may be modified by single experience learning, namely preference induction or averse conditioning. Both types of learning were acquired within 3 h of training. Experience was retained for over 3 days in the case of averse conditioning. Preference induction, a form of learning specific to insects, is expected to produce rigid host preference lasting for days if not weeks, but in codling moth neonates this type of memory was retained only for 3 h. We speculate that conjunction of preference induction with short retention time and averse conditioning with long retention time provide an optimal adaptive strategy of host fruit selection for codling moth neonates.