Incongruence between morphological data sets: An example from the evolution of endoparasitism among parasitic wasps (Hymenoptera : Braconidae)

Phylogenetic analyses of molecular and morphological data sets for a group of parasitic wasps (Hymenoptera: Braconidae) give strikingly different resu lts. The molecular data indicate that the major life history transition fro m ectoparasitism to endoparasitism has occurred independently several times within the family while the morphological data indicate a single origin. S imilar incongruent topologies are obtained if the morphological data are pa rtitioned by either of two methods: distinguishing (I) characters of the la rval stage and female reproductive system, or (2) characters selected indiv idually by the authors prior to the analysis as likely to be mechanisticall y associated with endo/ectoparasitism. This result is supported by signific ant differences in tests of incongruence, and we propose that it is caused by convergence among morphological characters resulting from a shared life history strategy.