Taxonomic description of Stenodiplosis tectori n. sp. (Diptera: Cecidomyiidae), a seed parasite of cheatgrass (Anisantha tectorum), based on morphological and mitochondrial DNA data

Authors: Rector, Brian; GAGNÉ, RAYMOND - Retired Non ARS Employee; PERILLA LÓPEZ, JUAN MANUEL - Wright State University; Tonkel, Kirk; BON, MARIE-CLAUDE - European Biological Control Laboratory (EBCL); GUERMACHE, FATIHA - European Biological Control Laboratory (EBCL); CRISTOFARO, MASSIMO - Biotechnology And Biological Control Agency

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2021
Publication Date: 8/22/2021
Citation: Rector, B.G., Gagné, R.J., Perilla López, J., Tonkel, K.C., Bon, M., Guermache, F., Cristofaro, M. 2021. Taxonomic description of Stenodiplosis tectori n. sp. (Diptera: Cecidomyiidae), a seed parasite of cheatgrass (Anisantha tectorum), based on morphological and mitochondrial DNA data. Insects. 12(8), 755. https://doi.org/10.3390/insects12080755.
DOI: https://doi.org/10.3390/insects12080755

Interpretive Summary: Cheatgrass is an annual grass species from Eurasia that has become invasive in much of western North America. It has been implicated in the recent increases in the frequency, size, and intensity of wildfires, contributing to severe economic, environmental, and social destruction. In order to reduce this damage, 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 DNA fingerprint comparisons with other Stenodiplosis spp. The present study is the first to report DNA fingerprint data in the genus Stenodiplosis. The DNA fingerprint results 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.

Technical Abstract: Cheatgrass is an annual grass species from Eurasia that has become invasive in much of western North America. It has been implicated in the recent increases in the frequency, size, and intensity of wildfires, contributing to severe economic, environmental, and social destruction. In order to reduce this damage, 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 (COX 1) 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.