One of the most challenging issues

One of the most challenging issues faced by scientists working on the whitefly B. tabaci is its unsettled species status. While the genetic diversity and complexity of B. tabaci has long been recognized, the levels of separation within B. tabaci and the nomenclature of the various genetic groups have been a subject of debate. Liu et al. (2012) provide an exhaustive update on experimental studies examining the reproductive isolation among various genetic groups of B. tabaci. In view of the lack of morphological variations reliable for classification, the authors argue for the need to apply the biological species concept in order to elucidate B. tabaci’s systematics. While the datasets of crossing experiments and behavioural observations available so far indicate a consistent pattern of reproductive isolation among the putative species, as identified by mtCOI genetic groups , many more experimental studies are critically needed. The authors examine the technical and conceptual complexities associated with research efforts to reveal reproductive isolation and elaborate on a strategy for future research on the systematics of this species complex. While the recent phylogenetic analyses using mtCOI have revealed the relationships between members of the B. tabaci species complex in a more structured and systematic way, many questions remain . De Barro (2012) uses the largest available mtCOI dataset that spans the full diversity of B. tabaci and explores the phylogenetic relationships in greater depth and detail. This extensive analysis discerned ten notable features from the phylogeny and provided a number of interesting insights that were used to formulate questions for future research. For example, the analysis may help the science community to develop the most effective strategy in applying the biological species concept to studying the systematics of B. tabaci, as advocated by Liu et al. (2012).