Molecular markers to differentiate two morphologically-close species of the genus Sitobion

A set of molecular markers to differentiate the aphid (Hemiptera: Aphidoide a) species Sitobion avenae (Fabricius) from Sitobion fragariae (Walker), is presented. These markers correspond to (1) a region of the mitochondrial D NA, (2) five species-specific RAPD banding patterns and (3) four microsatel lite loci. Each of the markers was able to clearly distinguish between the species. The utility of each molecular marker is discussed. Mitochondrial D NA is best applicable to species determination and relative abundance, RAPD s to the evaluation of genetic diversity, and microsatellites to the assess ment of the population genetic structure; the combined use of mtDNA with th e other techniques can be of importance when the presence of hybrids is sus pected, and RAPDs with microsatellites are best used together in population genetics and host preference studies.