POPULATION-GENETICS AND GENE VARIATION IN THE PREDATOR, COLEOMEGILLA-MACULATA (DEGEER) (COLEOPTERA, COCCINELLIDAE)

An electrophoretic study of 23 allozyme loci in 15 populations of the predaceous ladybird beetle Coleomegilla maculata (De Geer) revealed ex tensive genetic polymorphism occurring as low-frequency allelic variat ion averaging four alleles per locus. Although all loci except GOT-2 d emonstrated variation, only 69% of the loci were polymorphic when the rare allele occurred at >5% frequency. The average observed population heterozygosity index demonstrates a north-south cline with higher all elic variation associated with both lower latitudes and corn-sorghum c rop types. Nei's genetic distance values suggests high genetic identit y among all populations, with some clustering based on geographic loca le. We conclude this Iadybird beetle is genetically very variable, and that some of this variation is maintained by selection.