Feeding and oviposition rates in the pine weevil Hylobius abietis (Coleoptera : Curculionidae)

Feeding and oviposition in the pine weevil Hylobius abietis (Linnaeus) were monitored under laboratory conditions in two long-term experiments lasting over an extended breeding season. Data were also collected from weevils under semi-natural conditions outdoors. In addition, the effects of crowding and starvation were studied in separate experiments. During the main peak oviposition period, female H. abietis consumed 50% more bark tissue than males. When oviposition ceased, the feeding rate of the females declined to the same level as in the males. The rates and spatial distribution patterns of oviposition and feeding were clearly affected by climatic conditions and the degree of crowding. Females were estimated to lay on average 0.8 eggs per day during the season under outdoor conditions. The realized fecundity of a female weevil during the first season was estimated to be approximately 70 eggs. The estimated average rate of feeding was 23 mm(2) of Scots pine bark per weevil per day. This implies that planted seedlings can only constitute a minor part of the food resources needed to sustain H. abietis populations of the size that usually appear on fresh clear-cuttings in northern Europe.