Quality changes in successive generations of the millet stem borer,Coniesta ignefusalis (Hampson) (Lepidoptera : Pyralidae), in northern Ghana

Studies were conducted in northern Ghana in 1996 and 1997 to assess any changes in the quality of insects in different generations of the millet stem borer, Coniesta ignefusalis (Hampson), over the growing season. The goal was to determine if, and to what extent, such changes are responsible for observed differences in the sizes of populations of successive generations of the insect. Pupae from diapause larvae gave rise to adults that were significantly smaller and had lower reproductive rates than those derived from non-diapause larvae. There were, however, no significant differences between the non-diapause generations for all the quality indicators studied. The results suggest that observed differences in the sizes of generations developing fromnon-diapause anddiapause larvae of C. ignefusalis are, at least, partly due to differences in the inherent quality of individuals of these generations.