OVIPOSITION PATTERNS OF THE PINE WEEVIL HYLOBIUS-ABIETIS

Spatial and temporal distributions of eggs laid by the pine weevil Hyl obius abietis (L.) (Coleoptera: Curculionidae) were studied by taking root and soil samples around pine stumps on a clear-cutting in central Sweden. In addition, first-instar larvae migrating in the soil were s ampled using traps baited with host-odour. Eggs were found in the soil rather than in the bark of stump roots, which previously has been reg arded as the usual oviposition site. Based on an oviposition experimen t and additional field observations we conclude that eggs are laid in the bark of roots only when the surrounding material is likely to dry out. We suggest two explanations for why weevils oviposit mainly in rh p soil although they arp known tn show stereotypic behaviour when inse rting eggs in stump roots: (1) egg predation by other arthropods or by conspecifics is avoided, and (2) newly hatched pine weevil larvae are better than ovipositing females at locating suitable sites for larval feeding.