Angewandte Zoologie / Ökologie der Tiere, Institut für Biologie, Freie Universität Berlin,Haderslebener Str 9, 12163 Berlin, Germany.
According to the "Hopkins host-selection principle" the feeding and oviposition behaviour of a herbivorous insect is not only influenced by experience of the adult insect, but also by experience obtained during the larval stage. However, until now there is no unequivocal experimental proof for a memory transfer from the larval to the adult stage in herbivores. Therefore the influence of larval feeding experience was examined with adults of the granary weevils Sitophilus granarius (L.) in an olfactometer. To exclude the influence of early adult experience the weevils were removed during the pupal stage from the seeds they developed in. The experiments revealed that when given the choice between seeds of maize and wheat the adult weevils preferred the odour of those plant seeds, in which they had developed. Experience with seed volatiles at the time of emergence from the pupal stage increased this effect. Thus, olfactory preferences of the adults are influenced by experience obtained during the larval stage and as early adult. These results are discussed with respect to the "Hopkins host-selection principle" and the "hierarchy-threshold model" (Courtney et al., 1989).