A morphological and molecular analysis ofGryonHaliday (Platygastroidea, Scelionidae) was conducted to provide a taxonomic and phylogenetic context for a species under evaluation as a biological control agent ofBagrada hilaris(Burmeister) (Hemiptera, Pentatomidae). Our analysis revealed thatGryonis polyphyletic and that the biological control agent is notG. gonikopalense, a name that was tentatively applied to this species in 2019. We here describe this species as new,Gryon aetheriumTalamassp. nov., and resurrect the generic nameHadronotusFörster. Morphological characters that delimit our concepts ofGryonandHadronotusare presented. Based on morphological characters and multilocus phylogenies, we determined that five presently valid scelionid genera belong withinGryon. In total, 15 species are transferred intoGryonfrom these genera, 215 species are transferred fromGryontoHadronotus, and 6 species are transferred fromGryontoDyscritobaeusPerkins. Specimens collected during field studies in California and reevaluation of specimens determined asG. myrmecophilumin Mexico reveal thatG. aetheriumis adventive in North America.

Species of the genus Protelenomus Kieffer (Platygastroidea, Scelionidae) are phoretic egg parasitoids of coreid bugs. The discovery, DNA sequencing, and molecular phylogenetic analysis of a Protelenomus species phoretic on Cletus punctiger (Dallas) (Hemiptera, Coreidae) shows that Protelenomus is a derived lineage of Trissolcus Ashmead. Protelenomus is treated as a junior synonym and a new species of phoretic Trissolcus, T. siliangae Yan, Chen & Talamas, is described from China.

The pomegranate butterfly Deudorix (= Virachola) livia is the major pest of pomegranate, a crop of economic importance, in Oman. A species of parasitoid wasp in the hymenopteran family Scelionidae is responsible for high levels of mortality of its eggs. This wasp is described herein as Telenomus nizwaensis Polaszek sp. n., based on morphology and DNA sequence data. T. nizwaensis is currently known only from D. livia, which is also a pest of economic importance on other crops in North Africa, the Arabian Peninsula, and the Mediterranean. We summarise current knowledge of T. nizwaensis life-history and its potential to provide biological pest control.

In the past decade, several species of platygastroid wasps were found to be adventive in North America and Europe while under evaluation in quarantine as biological control agents of invasive pests. The scope and relative risk of this phenomenon is not fully known, but it is clearly a trend with implications for classical biological control. As a means of assessing the issue and to provide a global baseline, we implemented a data-mining approach with DNA sequences in the Barcode of Life Database, yielding 201 platygastroid BINs with intercontinental and island distributions. At least fifty-five BINs displayed exact COI barcode matches across continents, with many more BINs scored as inconclusive due to sequence length variation. These intercontinental and island BINs include biocontrol agents known to be adventive, as well as many species identified only to genus with uncertain geographic origins. We provide 2,500 identifications for platygastroid BOLD BINs, 88% to genus, to encourage additional research on this distributional phenomenon. The intercontinental BOLD BINs were compared to literature records and GBIF occurrences of cosmopolitan species to identify gaps and discordance across data sources. Smaller COI barcode datasets from localities in Florida and Germany, including topotypical specimens, revealed more intercontinental matches. We analyzed COI sequences in BOLD for the entirety of Insecta and Araneae to assess this phenomenon more broadly and because these taxa contain many hosts for platygastroid wasps. This method revealed that the intercontinental distribution phenomenon is widespread with implications for assessing biological diversity, taxonomic methodology and regulatory frameworks.

The genus Alfredella Masner & Huggert is revised. Alfredella tasmanica Masner & Huggert is redescribed, Al. teres (Buhl), comb. nov. is transferred to Alfredella from Amitus Haldeman, and Al. auriel Lahey, sp. nov. (New South Wales, Tasmania) and Al. mephisto Lahey, sp. nov. (Western Australia) are described as new. The genus Masnerium Polaszek, syn. nov. is treated as a junior synonym of Amitus, and its type species, M. wellsae Polaszek, is transferred to Amitus as Am. wellsae (Polaszek), comb. nov. The relationship between Alfredella and morphologically similar genera is discussed, and a key is provided to distinguish between Aleyroctonus Masner & Huggert, Alfredella, and Amitus.