Genetic differentiation in Tetranychus urticae (Acari: Tetranychidae): polymorphism, host races or sibling species?

摘要: Based on allozyme electrophoresis at the Pgm locus and nuclear ribosomal DNA (ITS2) sequences, we studied genetic variation of two-spotted spider mite Tetranychus urticae Koch collected rose bay, Nerium oleander L. (Apocynaceae), from several localities around Mediterranean basin. In addition, compared these results with those Navajas et al. (1998) Tsagkarakou (1997) who other host plants Mediterranean. western part this area (Spain, France, Tunisia), found individuals bay to be clearly genetically differentiated samples. No evidence such host-associated differentiation was detected in eastern (Italy Greece). The mites investigated further by studying reproductive incompatibilities between populations Greece France a laboratory strain reared bean, Phaseolus vulgaris, France. Reciprocal crosses performed strains revealed variable levels incompatibility, spanning partial complete isolation. all cases incompatibility asymmetric. We designed test based double-mating establish fertilization status females fully incompatible crosses. These showed that had been inseminated, which suggests barrier reproduction is not prezygotic behavioral nature. data raises question relative role ecological factors (host plant) geographical distance, ongoing process potentially leading speciation.