The major opsin gene is useful for inferring higher level phylogenetic relationships of the corbiculate bees.

The phylogeny of the corbiculate bees, which include the major groups of highly eusocial bees, is controversial. In an attempt to resolve the controversy, Ascher et al. (2001) argued that they have expanded a prior phylogenetic analysis of the corbiculate bees based on opsin (LW Rh) sequences reported by Mardulyn and Cameron (1999) ‘‘to more critically assess opsin s phylogenetic utility.’’ They contended that all previous molecular studies of corbiculate bee phylogeny suffer from including too few outgroup taxa. Several additional conclusions stand out in their paper. One is that the monophyly of the ingroup (the corbiculate bees) cannot be unequivocally substantiated, just as Mardulyn and Cameron (1999) and, more recently, Cameron and Mardulyn (2001) found in their analyses. Second, in contrast to Mardulyn and Cameron, Ascher et al. stated that their expanded opsin data set shows little support for relationships among the ingroup corbiculate tribes. Third, they found that when they combined their data set with morphological and behavioral data for the corbiculate bees, the results supported the classical view of relationships among the tribes (((Apini +Meliponini) +Bombini) +Euglossini). We take issue with each of these claims and stand by our original conclusions that LW Rh is useful to infer phylogenetic relationships of corbiculate bees. The opsin gene clearly contains phylogenetic information to resolve relationships among the tribes of corbiculate bees and, more importantly, this phylogenetic information is consistent with all other genes thus far studied in this group (28S, cytochrome b, and 16S; see Cameron and Mardulyn, 2001; Ef-1a, Sipes, Danforth, and Cameron,