Hetero zygosity and genetic distance in sibling species of meat ants iridomyrmex purpureus group
Evolution 35(2): 234-242
ISSN/ISBN: 0014-3820 DOI: 10.2307/2407834
Meat ants (I. purpureus group) occur in at least 8 recognizable color forms, which together occupy most areas of Australia. In areas where they are sympatric, some combinations of color forms have few or no alleles in common at a polymorphic allozyme locus (Amylase). This observation, together with other evidence, suggests that they are reproductively isolated and should be recognized as different biological species. Of the color forms, 5 were surveyed for genetic variation at 15 enzyme and protein loci. The average level of heterozygosity was 3.8%, and an average of 11.8% of loci was polymorphic in each population. These values are similar to those found in many other species of Hymenoptera, but are unusually low when compared with other insects. The average genetic distance (Nei's D) between color forms was 0.06, indicating that genetic differentiation between them is very limited. Ecological and morphological divergence between color forms may have been prevented by intense competitive pressure from many other ant species with which meat ants co-exist.