Abstract

This research focused on Dacnusini, a tribe of ~520 parasitoid wasp species. Dacnusines attack plant-infesting flies and have been used in biological control. The overall goal of this research was to increase taxonomic stability for Dacnusini to facilitate their use in biological control. Quantitative cladistic analyses were conducted for Dacnusini to assess the limits of several genera. The New World species of Chaenusa sensu lato were revised to disseminate information on the identification and biology of species in this genus.

Recent classifications of Dacnusini have ranged from 15 genera and three subgenera to 22 genera and 11 subgenera. Cladistic analyses using external morphology were conducted to examine the monophyly of genera and relationships among species. Symphya and the Coelinius s.l. subgenera Lepton and Polemochartus were recovered, as was the Chorebus senilis-group s.l. Chaenusa s.l. and Coelinius s.l. were recovered depending on the method used for coding polymorphism. Aristelix phaenicura was positioned in the Coelinius s.l. clade in one analysis, indicating that Coelinius s.l. may be paraphyletic. The status of Sarops as a junior synonym of Coelinius s.l. was confirmed. Twenty-eight apomorphies were identified, including a previously undetected apomorphy for Coelinius sensu stricto.

The New World species of Chaenusa s.l. were selected for revision because they had not been treated in 24 years, specimens were available, and certain species of Chaenusa s.l. attack economically important flies. The revision included descriptions for six new and six previously described species. Three species were transferred to Chaenusa s.l. , and four new synonyms were designated. Host utilization and spatiotemporal distribution data were presented for each species, including several new records. The status of several holotypes was resolved, and an illustrated key to species was provided.

Chaenusa has been treated as one broad genus or split into Chaenusa s.s., Chorebidea, and Chorebidella . Cladistic analyses using mitochondrial ND1 sequences were conducted to assess the monophyly and interspecific relationships of Chaenusa s.l., Chaenusa s.s., Chorebidea, and Chorebidella. Chaenusa s.l. and Chorebidea were not monophyletic, but Chaenusa s.s. and Chorebidella were recovered. Despite the lack of support, Chaenusa s.l. should be retained pending analyses using nuclear genes and morphology.