The diverse superfamily Oestroidea with more than 15 000 known species includes among others blow flies, flesh flies, bot flies and the diverse tachinid flies. Oestroidea exhibit strikingly divergent morphological and ecological traits, but even with a variety of data sources and inferences there is no consensus on the relationships among major Oestroidea lineages. Phylogenomic inferences derived from targeted enrichment of ultraconserved elements or UCEs have emerged as a promising method for resolving difficult phylogenetic problems at varying timescales. To reconstruct phylogenetic relationships among families of Oestroidea, we obtained UCE loci exclusively derived from the transcribed portion of the genome, making them suitable for larger and more integrative phylogenomic studies using other genomic and transcriptomic resources. We analysed datasets containing 37–2077 UCE loci from 98 representatives of all oestroid families (except Ulurumyiidae and Mystacinobiidae) and seven calyptrate outgroups, with a total concatenated aligned length between 10 and 550 Mb. About 35% of the sampled taxa consisted of museum specimens (2–92 years old), of which 85% resulted in successful UCE enrichment. Our maximum likelihood and coalescent‐based analyses produced well‐resolved and highly supported topologies. With the exception of Calliphoridae and Oestridae all included families were recovered as monophyletic with the following conclusions: Oestroidea is monophyletic with Mesembrinellidae as sister to the remaining oestroid families; Oestridae is paraphyletic with respect to Sarcophagidae; Polleniidae is sister to Tachinidae; Rhinophoridae sister to (Luciliinae (Toxotarsinae (Melanomyinae + Calliphorinae))); Phumosiinae is sister to Chrysomyinae and Bengaliinae is sister to Rhiniidae. These results support the ranking of most calliphorid subfamilies as separate families.

Natural biological control is one of the major causes responsible for reduction of pest population in agricultural ecosystem. However, natural biological control importance is usually minimized by not being estimated. This study reports the occurrence of Campoletis sonorensis (Cameron, 1886) (Hymenoptera: Ichneumonidae), Archytas marmoratus (Townsend, 1915) and Archytas incertus (Macquart, 1851) (Diptera: Tachinidae) associated with Helicoverpa armigera (Hübner, 1809) (Lepidoptera: Noctuidae). The rate of larval parasitism was up to 41% in structured refuge areas of cotton, without chemical control with insecticides. This study strengthens our knowledge relating to parasitoids associated with natural control of H. armigera in the American continent. In addition, it documents the rule that structured refuge areas could play as a source of natural enemies, besides their contribution to production of non-selective populations to Bt technology.

Stenodiplosis spartinae Gagné new species (Diptera: Cecidomyiidae) is described from eastern South Dakota and coastal North Carolina, and compared with other American congeners. The known host plants are Spartina alterniflora and S. pectinata. The larva is a seed predator of the ovule and immature caryopsis of the host plant. Adult activity is from the early emergence of the host inflorescence through anthesis. Oviposition occurs in the floret with eggs laid under the edges of the palea and lemma. The larva apparently overwinters in dehisced spikelets in the soil among rhizomes of S. pectinata, with pupation in late spring. Laboratory emergence and field activity of the adults suggest a potentialsecond or third generation developing on late emerging inflorescences. Larval feeding does not induce external color or shape changes in the spikelet. Apparently all three instars are ectoparasitized by Tetrastichus bromi Kostyukov (Hymenoptera: Eulophidae) that was probably introduced to North America in the late 1800's and is inculcated into parasitoid guilds of several Stenodiplosis species. Resource partitioning appears to occur between the gall midge and early instars of Aethes spartinana Barnes and McDunnough (Lepidoptera: Tortricidae) that feed on maturing caryopses. The feeding of this gall midge and the moth probably account for most of the reduced seed production in both natural and agronomic populations of S. pectinata.

Cheatgrass is an annual grass species from Eurasia that has become invasive in much of western North America. It has been implicated in recent increases in the frequency, size, and intensity of wildfires, contributing to severe economic, environmental, and social destruction. In order to reduce this damage, the USDA-ARS established a classical biological control program against cheatgrass. In 2018 and 2019, adult gall midges were collected emerging from cheatgrass seed heads collected at several sites in Bulgaria and Greece; this is the first gall midge ever recorded from cheatgrass. Morphological comparisons with related midge species recorded from other plant hosts revealed that this midge from cheatgrass is a new species, described here as Stenodiplosis tectori n. sp. This status was supported by sequence comparisons of a barcode region of the gene encoding the mitochondrial cytochrome c subunit I (CO1) protein in Stenodiplosis tectori n. sp. and three congeners. The present study is the first to report MT-CO1 data in the genus Stenodiplosis. The ingroup Stenodiplosis tectori n. sp. collected in the Balkans grouped in one phylogenetic supported clade, with an average K2P-distance from its closest related congener, S. sorghicola, of 7.73% (SD = 1.10). The findings indicated relatively high year-to-year within-population diversity. Implications for this gall midge’s utility as a biological control agent of cheatgrass are discussed.

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