The effect of dispersal ability in winter and summer stoneflies on their genetic differentiation

1. Plecopteran species disperse less than most other aquatic insects. Within stoneflies, members of different families vary in the degree of wing morphology and season of adult emergence. 2. Dispersal limitations were tested to determine if there were increased differences among the nearby, Chagrin and Grand River populations in north-eastern Ohio, by comparing genetic variation within the 16s rRNA region of mitochondrial DNA in two stoneflies. Allocapnia recta emerges in winter and often has rudimentary wings, and Leuctra tenuis emerges in summer with fully developed wings. 3. There was significant genetic variability between the samples of A. recta from two adjacent rivers (FST = 0.20), but not between samples of L. tenuis (FST = 0.07). 4. Distinct clades in A. recta were found to occur within the minimum spanning tree specific to the Chagrin River, which contributed to a significant difference in gene diversity between the two rivers. Haplotypes in L. tenuis appeared randomly distributed between the two rivers; however, nucleotide diversity was significantly less in samples from the Grand River. 5. Shared haplotypes of both species illustrate the inter-connectedness of the Chagrin and Grand River populations, and the lower genetic variability of L. tenuis between the two rivers is indicative of its greater dispersal capability. © 2007 The Royal Entomological Society.