Description of a new species of Euderus Haliday from the southeastern United States (Hymenoptera, Chalcidoidea, Eulophidae): the crypt-keeper wasp

Abstract

A new species of the genus Euderus Haliday, Euderus set sp. n., is described and illustrated from the southeastern United States, where it parasitizes the crypt gall wasp, Bassettia pallida Ashmead, 1896, on live oaks in the genus Quercus (subsection Virentes). This is the 1st species of the genus reported from the southeastern United States to parasitize cynipid gall wasps and the 3rd species of the genus reported to attack cynipids in North America. Modified sections of the identification keys to subgenera and species of Euderus (Yoshimoto, 1971) are included to integrate the new species.

A keeper of many crypts: the parasitoidEuderus setmanipulates the behavior of a taxonomically diverse array of oak gall wasp species

“…Morphological and genetic data together imply that all Euderus wasps reared in this study are E. set, the species described previously from Bassettia pallida [16], bringing its total number of confirmed hosts to seven. Euderus set remains the only endemic cynipid-associated Euderus known from the eastern half of North America.…”

“…Emergent animals included gall wasps and a large diversity of parasitoids, inquilines, and hyperparasitoids, which we identified to family or genus using taxonomic keys found in [19] and [20]. We identified Euderus to species using [18] and Egan et al [16]. Most gall wasp species are identifiable by their gall's morphology, such that keying out emerging adult gall wasps to species was largely unnecessary.…”

“…Most of the resulting fragments were 701bp in length, while the four sequenced in 2016 were 652bp, with 464 bp of overlap between the two fragment types. We generated a multiple alignment of these new Euderus mtCOI sequences and two known E. set sequences [16] ( Supplementary Table 2). For outgroups, we used sequences from NCBI from four other species in the same subfamily, including Euderus albitarsus and Euderus cushmanii, introduced and native North American (respectively) parasites of Lepidopteran pupae [18].…”

“…In Arizona and California, Euderus crawfordii has been reared from the native oak gall wasp Dryocosmus coxii on Emory Oak (Quercus emoryi) and Silverleaf Oak (Quercus hypoleucoides) [18,26], as well as from the introduced gall wasp Plagiotrochus suberi on non-native Cork Oak (Quercus suber) [27,28]. While we have no sequence data available for this southwestern species, the morphological resemblance [16] and similarity of habit between E. crawfordii and E. set suggest they may be sister to one another. Another possible cynipid parasitoid, Euderus albitarsis, was introduced to the Eastern U.S. for control of the western larch case bearer (Coleophora laricella [Lepidoptera: Coleophoridae]) [26], but the single reference to an association with an unknown cynipid [29] has no independent corroboration, so this record may be aberrant.…”

“…Two recent papers [16,17] describe the discovery and life history of the parasitoid "crypt keeper wasp" (Euderus set), so named because of its parasitism and behavioral manipulation of the "crypt-gall wasp" (Bassettia pallida) in live oaks (Quercus virginiana & Q. geminata). Oviposition by a B. pallida female into a young stem induces the formation of a swollen internal gall (known as a "crypt") inside the stem, where the developing larval wasp will then feed and grow.…”