morphometric and molecular variation in thrips tabaci lindeman (thysanoptera: thripidae) populations on onion and tobacco in iran

onion thrips, thrips tabaci lindeman, is a broadly distributed pest that attacks a wide range of crops. to investigate the intra-specific morphometric variation and the genetic diversity of the species in iran, four populations from tobacco plus 18 populations from onion were studied in some 17 provinces of iran. morphological analysis, using principal components and canonical discriminant analyses indicated that the populations living on tobacco were significantly different from those living on onion. dna sequence data for the coi gene was obtained for all the populations including some other 21 population sequences retrieved from the genbank database. maximum parsimony analyses revealed the distinct clades of t. tabaci on tobacco and on onion with the exception of one population collected from tobacco grown in golestan province. the results were identical for maximum likelihood and neighbor-joining analyses. both molecular and morphometric analyses show heterogenecity of t. tabaci populations representing at least two different biotypes on tobacco and on onion.