Eucharitidae (Hymenoptera): phylogeny, biogeography, and host ant associations

The 53 genera and over 425 described species of Eucharitidae (Hymenoptera: Chalcidoidea) are exclusively parasitoids of immature Formicidae. Morphology, molecules, and shared life history traits unite the Eucharitidae as a demonstrably monophyletic group with three subfamilies: Gollumiellinae, Oraseminae, and Eucharitinae. We present a fossil-calibrated molecular phylogeny based on a dataset of over 175 taxa from both the Eucharitidae and its sister group, the Perilampidae. Molecular evidence from a combined-gene dataset (18S, 28S-D2, 28S-D3-D5, COI, and COII) is used to assess relationships of the major eucharitid clades. In addition, patterns of host ant use will be examined by comparing our eucharitid phylogeny with the most recent formicid phylogenies. Estimates from molecular divergence dating studies suggest an origin of Eucharitidae at roughly 60-75 mya, while major ant lineages diverged much earlier, over 100 mya. We found no significant cophylogenetic relationship between eucharitid and ants, suggesting adaptive host shifts and subsequent radiation on established ant lineages as the means of eucharitid host diversification.