SELECTION OF FRUITS FOR OVIPOSITION BY THE CHESTNUT WEEVIL, CURCULIO-ELEPHAS

Under field conditions, females of the chestnut weevil Curculio elepha s select their oviposition sites. In sleeve experiments, when the numb er of fruits is limited, females avoid 17% of available chestnuts and concentrate their eggs in the others. In the field, on average, 56.3 a nd 27.8% of the infested fruits contain one or two immatures (eggs and larvae). The oviposition site selection is neither influenced by host size nor by the presence of immature conspecifics. Choice experiments in the laboratory suggest that female weevils do not deposit repellen t chemical markers on the fruits. Moreover, sleeve experiments indicat e that selection is not influenced by the noise made by larvae while f eeding inside a fruit. In general, the most probable hypothesis is tha t Curculio elephas exploits only hosts of highest feeding quality.