Density-Dependent Induction of Diapause in the Codling Moth, Laspeyresia Pomonella (Lepidoptera: Olethreutidae)

Data are presented which show that first brood codling moth larvae have a higher diapause rate (and are thus univoltine) if reared in apples crowded with other larvae than if they are reared in uncrowded apples. From this relationship, a theoretical mechanism is proposed to help explain the interaction of genetic and nutritional effects in determining the dominant voltinism strain in codling moth populations.