Planidial larval traits and resolving relationships in the ant parasitoid Eucharitidae (Chalcidoidea: Hymenoptera)

Within Chalcidoidea, a Planidial Larval Clade (PLC) is defined by the presence of mobile first-instar larvae that actively seek out their host. Included are the Eucharitidae, which are exclusively parasitoids of ants. Within Eucharitidae, the planidia are highly sclerotized, mobile, and have distinct morphological traits that are highly conserved across higher-level groups. Based on molecular data, there are two competing phylogenies within the tribe Eucharitini. One older phylogeny, based on Sanger sequencing, aligns with adult morphology and ancestral host shifts, and another newer phylogeny, based on Anchored Hybrid enrichment data, presents a less clear host ancestry. I will be exploring highly conserved character traits of the planidia to evaluate the competing hypotheses of the relationships within the tribe Eucharitini. Planidial larval traits in Eucharitidae have not been studied since Heraty and Darling (1984). An update to this unique life stage in this unique family of parasitoid wasps is necessary and may provide some resolution to the intra-familial relationships within Eucharitidae.