Population genetic structure of two water strider species in the Ecuadorian Amazon

1. We used mtDNA sequence variation to estimate population genetic structure between and among water strider populations of Potamobates williamsi and P. sumaco in the Ecuadorian Amazon. 2. Sequencing of the COI mitochondrial gene revealed 16 haplotypes, which were summarised into four haplotype groups. P. williamsi and P. sumaco shared two common and widespread haplotypes. 3. Population structure was moderate and gene flow was low. Both air and river distances were significantly correlated with gene flow and, thus, indicative of isolation by distance. 4. The genetic structure within and among populations of P. williamsi and P. sumaco was probably not influenced by the dynamic tropical lotic system.