Comparative Studies of Three Populations of the Lady Beetle Predator Hippodamia convergens (Coleoptera: Coccinellidae)

Allozyme electrophoresis showed much genetic variation in Hippodamia convergens, suggesting the possibility of geographic genetic differentiation. Twenty-two of 31 putative allozyme loci resolved on acrylamide gels from H. convergens populations were polymorphic (71%). Heterozygosity (diversity) averaged over all loci was 21.3 ± 4.2%. However, thirteen polymorphic loci examined in F1 Honduran × Iowa hybrids indicated that all alleles were shared in the two populations. In addition, no significant geographic variation was observed in developmental and reproductive responses of H. convergens from Iowa, California, and Honduras to aphid prey densities. All inter-population and backcrosses produced fertile eggs. Adult body size of H. convergens from Iowa and Honduras was similar. This study indicates that augmentatively released California H. convergens could successfully mate with local H. convergens populations in Iowa and Honduras.