Genetic structure, diversity and demography based on mitochondrial DNA analysis of Cheilomenes sexmaculata (Coleoptera: Coccinellidae)

Abstract

AbstractCheilomenes sexmaculata (Coleoptera: Coccinellidae) is widely distributed from intermediate latitude to equatorial regions. Here, we examined its genetic structure and diversity based on a 627 bp region of the mitochondrial COI gene. We then estimated its demographic changes over the past 30 000 years. We observed 22 haplotypes in 339 individuals from 29 sites in Japan and Taiwan. The 22 haplotypes were integrated into two haplotype groups: one group exists at higher frequencies in lower latitudes (22–26°N), whereas the other group appears at higher frequencies in higher latitudes (30–37°N). The effective population size of the group that predominates in higher latitudes increased from 15 000 to 10 000 years before present. In contrast, the size of the lower‐latitude group has remained constant for 30 000 years. These data suggest that C. sexmaculata might have expanded its distribution northwards and could be increasing its population size since the last glacial period.