Reproductive development and maternal effects in the pine weevil Hylobius abietis

1. In a laboratory study of maturation feeding of female pine weevil Hylobi us abietis on current and 1-year-old stem bark of transplants of Scots and Corsican pine, Norway and Sitka spruce, Douglas fir, and hybrid larch, the length of the pre-oviposition period was influenced by the species on which weevils fed. The shortest pre-oviposition period was on hybrid larch (11.8 days) and the longest on Douglas fir (15.5 days). 2. The species on which weevils fed also affected fecundity but there was e vidence of a species-year interaction. Over a period of 36 days, most eggs were laid by weevils feeding on current stem of Norway spruce and Corsican and Scots pine and fewest on current stem of Sitka spruce. 3. Significant maternal effects on egg size were observed both in relation to female size and conifer species. The largest eggs were laid on Corsican pine and the smallest on Douglas fir, with no evidence of a trade-off betwe en number of eggs laid and their size. 4. There was a positive relationship between egg and larval size and betwee n larval size and survival on logs of four conifer species. Residual resist ance mechanisms in the bark of recently cut stumps and larval competition a re discussed briefly in relation to the importance of the observed maternal effects on weevil population dynamics.