The Hymenoptera – ants, bees and wasps – represent one of the most successful but least understood insect radiations. Recent estimates suggest anywhere from 0.3 to 2.5 million species may exist. Our research provided the first comprehensive molecular and morphological study spanning the entire order. Both molecular and morphological approaches were used to analyze the relationships of 116 species spanning all of the major lineages of Hymenoptera as well as other related taxa in the Insecta. Our hypotheses of evolution suggests a basal grade of phytophagous families giving rise to a single clade of parasitic Hymenoptera, the Vespina, from which predatory, pollen-feeding, gall-forming and eusocial forms evolved. Vespina represent the single origin of parasitism, or the ability to attack and develop on other insects. There was some discrepancy between the two analyses, but largely this was only in the placement of the insect family Orussidae and the hypothesis of a single origin of the narrow “wasp” waist and a closed hindgut in larval stages.

 Within Hymenoptera, one particular group, the Chalcidoidea, were a focal point of research. These represent one of the largest single major radiations of insect parasitoids, with 500,000 species estimated to exist. Most species are parasites of a variety of other insects, including aphids, whiteflies, armored scales and other pestiferous insects affecting our food crops. Economically and ecologically these are one of the most important groups for the control of insects in both natural and agricultural systems. Single species such as Aphytis lingnanensis  (figure), imported from Hong Kong, are responsible for the control of red scale on Citrus. A single importation of Neodusmetia sangwani controlled the Rhodegrass mealybug attacking pasture grass in Texas, resulting in billions of dollars of savings over the long term. Within Chalcidoidea, many species are used as successful biological control agents, often being moved between countries to track new pest invasions. However, we know very little about their relationships and evolution of traits affect their life history traits of interest. In one of the most important groups, Aphelinidae, common biological traits are often assumed and information for one group applied across all members. In our results, however, this group is comprised of a group of unrelated higher level groups. Thus assumptions from one may not be relevant to another, especially in regard to host relationships, flight mechanics, associations with different groups of endosymbionts and other features that affect their ability as effective control agents.

 We are proposing the first concrete hypothesis of evolutionary relationships for this superfamily. The diversity is staggering with more than 89 subfamilies and 19 families. These parasitic wasps are usually only 2-3 millimeters in size, but can be as small as 0.11 mm. Characterizing taxa is often difficult because of their minute size and associated reductions in structures. We have been able to sample a large proportion of the diversity both for morphology and molecules. To analyze morphology across such a diverse group, we worked in collaboration with researchers from around the world. Together we developed a web-based coding system to score a matrix of 243 characters that could be analyzed together with molecular sequence information from two ribosomal gene regions. Most of the subfamily groups are consistent with traditional hypotheses, but the relationships of higher level groups are more difficult to capture. No one data set (morphology or molecules) work alone to recover a reasonable set of relationships. This is due to both a proposed rapid radiation event of the group about 50 million years ago, and also with extreme convergence in morphological traits. Together the two data sets pro...

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