Gall Midges of the Genus Stenodiplosis Reuter (Diptera, Cecidomyiidae): Description of a New Species from the Northwestern Caucasus and Analysis of the Trophic Relationships

The genus Stenodiplosis includes 16 species that damage flowers and seeds of 27 species from 14 genera and 4 subfamilies of grasses (Poaceae): Pooideae, Chloridoideae, Panicoideae, and Arundinoideae. Six species of gall midges (37.5% of the total number), including 4 African ones, have been recorded on 14 species from 7 genera of Panicoideae. In the Palaearctic, the greatest umber of Stenodiplosis species (5) is associated with 9 species from 4 genera of the bluegrass subfamily Pooideae, on which gall midges are not found in other zoogeographic regions. The genus Stenodiplosis includes 5 invasive species, or 31.3% of the total number. The adult, larva, and pupa of the new species Stenodiplosis calamagrostidis sp. n. are described. This species damages flowers of Calamagrostis arundinacea, a new host plant for gall midges. This is the first record of gall midges of the subfamily Cecidomyiinae on the genus Calamagrostis; previously, only 6 species from 3 genera of stem gall midges from the subfamily Lasiopterinae were known on Calamagrostis. The diagnosis and morphometric features of the genus Stenodiplosis are amended, and data on the distribution and biology of its species are reported.