• Photoperiodism;
  • pupal diapause;
  • Sarcophaga bullata;
  • blowfly;
  • selection

ABSTRACT. This artificial selection study with the flesh fly, Sarcophaga bullata Parker, tested the hypothesis that phenotypic variability in the length of the larval stage (under non-diapause conditions) is largely a consequence of genetic variability. Selection for late pupariation resulted in a line that pupariated significantly later and also developed more slowly during other stages of the life cycle. In a diapause-inducing environment, the selected line pupariated later, showed a higher incidence of pupal diapause, and remained in diapause longer than the unselected line. This is the first experimental evidence in S.bullata to show that diapause incidence and duration are related. The relationship between developmental rate and diapause traits may stem from the pleiotropic effects of genes associated with late pupariation, or from one or more genes associated with late pupariation being closely linked to genes that affect diapause.