Genetic control of the pre-reproductive period in autographa gamma (L.) (silver Y moth) (lepidoptera: Noctuidae)

Abstract

Adults of the noctuid moth Autographa gamma undertake seasonal migrations into areas where they are unable to breed continuously. Individuals migrate into Britain each spring and offspring of these migrants probably return in autumn to over-wintering areas in North Africa and the Middle East, although the existence of these return migrations has been questioned. Insects usually migrate during the adults’ pre-reproductive period (PRP). The length of this period is therefore an index of migratory potential because individuals with longer PRPs have more time to express their potential for flight and to travel further. Significant, positive full-sib correlations showed that female offspring with long PRPs came from families where their brothers had correspondingly long PRPs. This suggests that the same genes control the rate of reproductive development in both sexes. There was a rapid response to selection for short and long PRP, with separation of the lines by the second generation of selection. Sib-analysis and parent-offspring regressions showed that the genes with the greatest influence on PRP are X-linked, although there is also an autosomal influence. The significance of X-linkage of genes controlling the PRP is discussed in relation to the migratory strategy of A. gamma. © The Genetical Society of Great Britain.