Chromosomal rearrangement involved in insecticide resistance of Myzus persicae

Abstract

POPULATIONS of the peach-potato aphid Myzus persicae (Sulzer) heterozygous for a particular translocation between autosomes 1 and 3 were first discovered in glasshouses in Great Britain1. A similar or identical trans-location was subsequently found to occur commonly in field populations of M. persicae in many parts of the world (Table 1). In tropical and warm temperate regions M. persicae is permanently thelytokous2, but survival of trans-location heterozygotes in the sexual cycle of the aphid, where a translocation would be expected to impose a severe genetic load3, has also been demonstrated4. Considerable resistance to organophosphorus insecticides is common in glasshouse populations of M. persicae5, and laboratory clones originating from glasshouses and isolated for such resistance are invariably translocated. A link between the translocation and organophosphorus resistance has been suspected, as this could provide the selective advantage which would explain the worldwide occurrence of translocation heterozygotes and their survival in the breeding system. However, no information has been available on the comparative resistance of translocated and normal aphids from most parts of the world. Populations with moderate organophosphorus resistance that appeared in the field on sugar beet in England in 1974 (ref. 6) had the normal karyotype, as also did a resistant clone originating from peaches in France in 1968. Now we report evidence that directly implicates the translocation in the organophosphorus resistance of M. persicae.