Molecular phylogenetics and evolution of generic diagnostic morphological features in the doryctine wasp tribe Rhaconotini (Hymenoptera: Braconidae)

The doryctine tribe Rhaconotini (Hymenoptera: Braconidae) is a cosmopolitan group of parasitoid wasps that currently comprises 13 valid genera. Despite the extensive taxonomic studies carried out for this tribe, its generic limits are still unclear due to the considerable variation of its diagnostic morphological features. Here we assessed the evolutionary relationships among representative species of eight rhaconotine genera based on mitochondrial and nuclear DNA sequence data. We also performed ancestral character reconstruction analyses of morphological features that are diagnostic at the genus level and assessed the times of origin and main diversification events in the tribe. The Rhaconotini was significantly supported as monophyletic. The widely distributed, speciose genus Rhaconotus Ruthe as well as Ipodoryctes Granger were recovered as non-monophyletic. Rhaconotus species with five visible metasomal tergites were nested in a single clade with the monotypic Aptenobracon Marsh, which also has this morphological feature. Most Rhaconotus species with six or more visible tergites were intermingled with other Oriental and Afrotropical genera that share this condition. The ancestral character reconstruction analyses of the remaining morphological features showed that they probably were gained and lost repeatedly during the evolution of the group. The origin and early diversification events in the Rhaconotini were estimated to occur during the late Eocene to mid-Miocene. Our results highlight the importance of assessing the evolution of diagnostic morphological features to improve the supraspecific classification of insect taxa with extensive morphological homoplasy.