Cheilosia (Cheilosia) orthotricha Vujić & Claussen, 1994

Fig. 50

Cheilosia orthotricha Vujić & Claussen, 1994: 261 .

Differential diagnosis

Cheilosia orthotricha is quite a large species (12–15 mm) characterized by the combination of a bare face, pilose eye, bicoloured legs and posterior margin of scutellum without bristles. It can be distinguished from most other Cheilosia with the same set of characters by the bare or sparsely pilose ventral part of the eye (entirely pilose in similar species). It forms a similar-looking trio with C. canicularis and C. himantopus, but generally in C. orthotricha pile on the pleura straight, unlike pile in C. canicularis and C. himantopus, which is wavy at apex, the pile on posterior anepisternum have straight apex (with wavy apex in the other two species) and face predominantly shiny (slightly pruinose in the other two species). The male genitalia are figured in Vujić & Claussen (1994).

Material examined

Cheilosia orthotricha was not collected in 2018, but collected in 2023.

GEORGIA – Mtskheta-Mtianeti • 2 ♂♂; Tbilisi N.P.; 41.880° N, 45.023° E; 1289 m a.s.l.; 4 May 2023; S. Bot leg.; SBA, SB.002715 = ZFMK-TIS-8028449, SB.002714 = ZFMK-TIS-8028450 • 2 ♀♀; same data as for preceding; SBA, SB.002712 = ZFMK-TIS-8028009, SB.002713 = ZFMK-TIS-8028010 • 4 ♂♂, 6 ♀♀; Tbilisi N.P.; 41.877° N, 45.0138° E; 1250 m a.s.l.; 4 May 2023; F. Van de Meutter leg.; FMT • 1 ♂, 1 ♀; same data as for preceding; ZFMK • 1 ♂; Tbilisi National Park; 41.8802° N, 45.0220° E; 1279 m a.s.l.; 4 May 2023; W. Opdekamp leg.; WOR, A051 • 6 ♀♀; same data as for preceding; WOR, A009, A011, A025, A043, A054, A055 • 1 ♀; Lutkhubi; 42.3930° N, 44.7929° E; 1700 m a.s.l.; 6 May 2023; W. Opdekamp leg.; WOR, A022 • 2 ♀♀; Lutkhubi; 42.3936° N, 44.7923° E; 1760 m a.s.l.; 8 May 2023; F. Van de Meutter leg.; FMT • 1 ♂; Lutkhubi; 42.3930° N, 44.7929° E; 1700 m a.s.l.; 8 May 2023; W. Opdekamp leg.; WOR, C032 • 1 ♂; Tbilisi N.P.; 41.8770° N, 45.0137° E; 1248 m a.s.l.; 9 May 2023; S. Bot leg.; SBA, SB.002710 • 1 ♀; same data as for preceding; SBA, SB.002711 .

Genetics

All DNA barcodes of C. orthotricha are clustered together with high support (BS = 99%). Within this cluster, two barcodes from Germany group together (BS = 100%) and five barcodes from Georgia cluster together (BS = 100%).

Remarks

Reported from the Caucasus, and Georgia, for the first time.Georgian individuals of C. orthotricha are genetically different from European populations (2.43–2.55%). We also found small morphological differences between populations in both regions. Our sample size for populations in both areas is too small to understand this variation, and for now we consider all populations belonging to one species.

Biology

During our expeditions, collected between 4 May and 9 May at an altitude between 1248 and 1760 m a.s.l. Nearly always found in close vicinity of its food plant Petasites hybridus L. Both sexes sit on leaves of the plant.

Distribution

Europe, Caucasus (Georgia).