Experience influences oviposition behaviour in two pyralid moths, Ephestia cautella and Plodia interpunctella

We investigated the importance of experience for oviposition behaviour in two pyralid moths, the almond moth, Ephestia cautella, and the Indian meal moth, Plodia interpunctella. We used two diets one based on wheat and the other consisting of nut-containing chocolate. Larvae were reared in one of the two diets (larval feeding) and then adults were exposed to the two diets during and after eclosion (pre-exposure). Larval feeding had an enhancing effect on the subsequent oviposition behaviour in E. cautella females, but not in P. interpunctella. This shows that the Hopkins' host selection principle to some extent applies in E. cautella. The pre-exposure strongly reinforced the ovipositional response to the previously encountered diet in both species. This effect might be caused by imprinting of the surrounding conditions in the females while emerging, and by stimulated oviposition when the imprinted cues are recognized by the gravid females. We observed both host location (flight) and host acceptance (oviposition), and the effect of experience was most prominent in the host acceptance step of the host selection behaviour. Since host acceptance is believed to be the most crucial decision step for offspring viability, this distinction was expected.