Colonization and persistence of urban ant populations as revealed by joint estimation of kinship and population genetic parameters

The decrease in biodiversity due to increasing urbanization has been well documented, but the processes of colonization and maintenance of wildlife populations in urban areas remain poorly understood. We address this issue using 462 individuals from 10 urban populations of the ant Formica japonica in Kobe City, Japan. We sampled workers regardless of colony identity, genotyped them using 6 microsatellite loci, and estimated allele frequencies and genotypes of reproductive individuals, together with other population genetic parameters, by estimating kinship structure using a likelihood method. Estimated genetic diversity and effective size of populations were not associated with environmental parameters, suggesting that populations are unaffected by urbanization. However, effective population sizes were small, and frequent population bottlenecks were detected. These results suggest that urban F. japonica populations are unstable, and the possibility of frequent extinctions and recoloniza...