GENETIC RELATEDNESS OF NORTH-AMERICAN POPULATIONS OF TOMICUS-PINIPERDA (COLEOPTERA, SCOLYTIDAE)

We used DNA fingerprinting by random amplified polymorphic (RAPD) DNA and electrophoretic characterization of esterase isozymes to investiga te the genetic relatedness of North American populations of the exotic bark beetle Tomicus piniperda (L.). Cluster analyses of genetic dista nces among populations identified the Illinois population as an outlie r population with mean genetic distances to other populations averagin g 0.895 (where complete dissimilarity = 2), compared with genetic dist ance averages of 0.595 among populations excluding Illinois. When gene tic distance means and geographical distance between populations were compared, the results suggested that T. piniperda populations in the U nited States were established separately in Illinois near Lake Michiga n and in Ohio along Lake Erie. Molecular markers indicated that insect s derived from the 2 founder groups were interbreeding in contiguous r egions in western Indiana.