Phylogenomics of Ichneumoninae (Hymenoptera Ichneumonidae) reveals pervasive morphological convergence and the shortcomings of previous classifications

Authors: SANTOS, BERNARDO - Smithsonian Institute; WAHL, DAVID - Utah State University; ROUSSE, PACAL - Sorbonne Universities, Paris; BENNETT, ANDREW - Agriculture And Agri-Food Canada; Kula, Robert; BRADY, SEAN - Smithsonian Institute

Submitted to: Systematic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2021
Publication Date: 4/24/2021
Citation: Santos, B.F., Wahl, D.B., Rousse, P., Bennett, A.M., Kula, R.R., Brady, S.G. 2021. Phylogenomics of Ichneumoninae (Hymenoptera Ichneumonidae) reveals pervasive morphological convergence and the shortcomings of previous classifications. Systematic Entomology. 46(3):704-724. https://doi.org/10.1111/syen.12484.
DOI: https://doi.org/10.1111/syen.12484

Interpretive Summary: Parasitic wasps attack insects that cause billions of dollars in damage to agricultural commodities and natural resources annually. The wasps treated in this paper attack plant-feeding insects, insects of medical and veterinary importance, and other natural enemies of insects. Genomic data were used to generate phylogenies for wasps in the largest subfamily within the most speciose wasp family. A new tribal classification was proposed based on the phylogenies. The phylogenies increase taxonomic stability, resulting in more efficient and accurate retrieval of information for economically important wasps, and also increase the ability to make accurate predictions about wasps as beneficial or antagonistic. The results facilitate additional systematics and ecological research on species in this group, furthering our understanding of their roles in insect pest management. This paper will be useful to scientists conducting research on these wasps, as well as personnel responsible for controlling and regulating pest insects.

Technical Abstract: The evolutionary history of the Ichneumoninae, the largest subfamily of ichneumonid wasps, is investigated using genomic ultraconserved elements (UCEs). The dataset includes 147 species in 130 genera of Ichneumoninae and 155 outgroup taxa from 19 subfamilies. Matrices with varying degrees of completeness and analyzed with different partition schemes were investigated and the resulting topologies were found to be mostly congruent. All analyses recovered Ichneumoninae as a monophyletic group, sister to all other Ichneumoniformes except Agriotypinae. Almost no support was found for previous tribal classification schemes, except that the tribes Phaeogenini and Platylabini are largely monophyletic. A new tribal classification is proposed taking the UCE tree into account, consisting of seven tribes: Alomyini Förster, Phaeogenini Förster, Notosemini Townes, Eurylabini Heinrich, Platylabini Berthoumieu, Ichneumonini Latreille and a new tribe, Abzariini Santos & Wahl, with the single genus Abzaria Cameron. As documented in other lineages of Ichneumonidae, pervasive morphological convergence poses a challenge to the development of suprageneric groups that are both monophyletic and diagnosable. Extremely short branches at the base of the Ichneumoninae clade suggest that the group may have undergone a rapid radiation when it first evolved, potentially associated with its specialization on lepidopteran hosts. Oxypygous and amblypygous abdomens have each evolved several times within the group, suggesting that morphological convergence is accompanied by multiple transitions in host use across the subfamily. The results demonstrate the power of phylogenomic approaches to resolve evolutionary relationships in hyperdiverse and poorly studied insect groups.