The effect of grain size on the biology of Sitophilus granarius L. (Col., Curculionidae). I. Oviposition, distribution of eggs and adult emergence

Abstract

Abstract: The oviposition and rate of emergence of Sitophilus granarius in two extreme sizes of wheat kernels was studied under 4 levels of population density. The behaviour of S. granarius was considered to be maladaptive, as in all tested population densities the zero level of aggregation was never recorded. With increasing number of grains available the aggregation of eggs decreased. In the mixed‐size samples large kernels were infested more frequently than small. However, the ratio of eggs laid on large versus small kernels was positively density dependent. In higher population densities, a higher load of eggs and adults per gramme of small grains was recorded. The importance of grain size, and of oviposition, in internally feeding granivores is discussed.