Pleistocene history of two Eastern North American stoneflies, Acroneuria frisoni and Allocapnia granulata

We investigated the effects of Pleistocene glacial cycles on the genetic structure of two North American stonefly species with different distribution, dispersal ability and life cycles. 348 specimens of Acroneuria frisoni Stark & Brown (Plecoptera: Perlidae) and 490 of Allocapnia granulata Claassen (Plecoptera: Capniidae) were collected from a total of 85 localities across their distribution range and were genotyped using mitochondrial gene cytochrome oxidase I (approximately 1500 base pairs). Results indicated that populations survived in glacial refugia located in the southern states on the west slope of the Appalachians throughout the Cumberland Plateau in Kentucky and Tennessee and west of the Mississippi in the Ozark and Ouachita Mountains of Missouri, Arkansas, Oklahoma and Texas. Populations from the Tennessee River drainage were the major contributors to the repopulation of the Midwest and Northern Appalachian. Populations distributed west of the Mississippi river have been isolated since before the last glacial episodes. Knowledge of the present genetic makeup and phylogenetic relationships amongst populations of A. frisoni and A. granulata increases our understanding of the history of aquatic biotas during the Pleistocene. Moreover, it is a basic step toward assessing the species’ conservation needs and is of foremost importance for predicting its capacity of coping with environmental changes due to global warming.