Protein polymorphism in natural populations of Diachasmimorpha longicaudata (Hymenoptera : Braconidae) in Thailand

Diachasmimorpha longicaudata (Ashmead) is a larval parasitoid of tephritid flies and is widely used as a classical biological control agent. We have u sed allozyme electrophoresis to evaluate the genetic relationships of six p opulations of D. longicaudata in Thailand. Twelve loci were examined of whi ch 11 were polymorphic in at least some populations, especially that of Nak ornratchasima. We observed a complete lack of heterozygotes for seven of th e 10 polymorphic loci in the Nakornratchisima female population, and a sign ificant deficiency of heterozygotes at a further two loci. We discuss possi ble hypotheses for these findings in light of the haplo-diploid sex determi nation system of these wasps.