ABSTRACT
An efficient sexing system is important for the release of sterile males for any control programme using the sterile insect technique. This study describes the development and characterization of a new genetic sexing strain from South Africa (GMK), needed for the planned implementation of such a programme in northern KwaZulu-Natal Province. The base colony used was a locally modified laboratory strain of Anopheles arabiensis containing a sex-linked gene conferring dieldrin resistance to male mosquitoes. Female A. arabiensis mosquitoes from northern KwaZulu-Natal were mated with these males and backcrossed to introduce the dieldrin resistance gene to the Y chromosome. The resulting strain therefore had an overall genotype representing the local population but with the Y chromosome containing the dieldrin resistance gene. Life-history characteristics, stability of the sex-linked resistance marker, and reduction in dieldrin waste were investigated. The strain showed semi-sterility exhibited by low egg hatch rates, faster development in the immature stages and longer adult survivorship compared with the parental strains. While the GMK strain carrying the dieldrin-resistant gene was successfully established, the stability of the gene is limited, requiring periodic purification. Dieldrin waste can be limited by treating many more eggs than currently recommended.
