Isozyme Polymorphism in Populations of the Pink Bollworm12

Thirty-one enzyme loci of individual insects from 2 strains of the pink bollworm, Pectinophora gossypiella (Saunders), the first collected from cotton fields in Phoenix, AZ, and the second a longterm laboratory colonized strain, were analyzed for allozyme variation on 7 electrophoresis buffer systems. Polymorphic variation was observed at 19 loci; 6 loci were monomorphic in both strains. The ADH locus had 5 alleles in the 2 strains. Four loci (ESTD, ME, 6-GPD, and PGM) had 3 alleles each; 14 loci (ADK, AO, APH, EST-B, GOT, α-GPD, G-3PD, HEX, IDH, LDH, MDH, PGI, SORDH, and SOD) each had 2 alleles. The number of alleles/locus and heterozygosity values were similar in the 2 strains, with only ADK and ME monomorphic in one strain but not in the other. The normalized genetic identity of genes between the 2 populations was calculated as 0.979. This value indicates little genetic divergence between the laboratory strain and the native strain examined in this study.