World Rileyinae (Hymenoptera: Eurytomidae): Classification and evolution.

摘要

Chalcidoidea includes 20 families of cosmopolitan parasitic hymenopterans ranging in size from 0.2mm to 15mm. They parasitize (rarely predate) a wide variety of immature arthropods: 12 orders of Insecta, two orders of Arachnida and one family of Nematoda. Eurytomidae is a morphologically distinct family of Chalcidoidea in which phytophagy appears uniquely derived. Within Eurytomidae, Rileyinae is a distinct subfamily characterized by a reduced prepectus, foreshortened anterior gastral terga and the presence of 2--3 anelli. Current research focuses on revising worldwide taxa and hypothesizing phylogenetic relationships within Eurytomidae and Rileyinae.; Morphological and molecular datasets were analyzed in order to determine relationships supported by each alone and in combination. Forty-one morphological were scored across 52 taxa (including 23 genera of Eurytomidae, 10 species of Rileyinae and 3 outgroup taxa) and analyzed using maximum parsimony with PAUP*.; Characters supporting the monophyly of Eurytomidae do so weakly due to homoplasy and/or plesiomorphy, while Rileyinae has better synapomorphic support. Molecular data consists of an ∼863 base pair nucleotide sequence of the D2 expansion region 28S rRNA transcript, sequenced for 34 taxa (16 Eurytomidae---including Rileyinae). Analytical results support a polyphyletic Eurytomidae with Rileyinae recovered as monophyletic in most analyses. In general, there is weak support for subfamily/family level groupings, with the exception of Rileyinae and some sister group (Chalcididae) subfamilies. Analysis of the merged datasets results in recovery of the generally "accepted" hypothesis of relationships: monophyletic Eurytomidae, Rileyinae and all sister taxa. Conflicting phylogenetic signal in separate analyses appear to be ameliorated in combination.