Cheilosia ( Cheilosia ) variabilis ( Panzer, 1798 )

Bot, Sander, Mengual, Ximo, Meutter, Frank Van de & Skevington, Jeffrey H., 2025, Review of the genus Cheilosia Meigen, 1822 (Diptera: Syrphidae) from the Caucasus, with the description of 14 new species, European Journal of Taxonomy 1023, pp. 1-181 : 150

Cheilosia ( Cheilosia) variabilis ( Panzer, 1798)

Fig. 77

Syrphus variabilis Panzer, 1798: 10 .

Cheilosia variabilis – Stackelberg & Richter 1968: 249. — Stackelberg 1970: 59. — Barkalov 1993: 714. — Gujabidze 2002: 245. — Mengual et al. 2020: 21 (part). — Żóralski & Bystrowski 2021: 26.

Differential diagnosis

The combination of eye and face with pile and black legs of Cheilosia variabilis distinguish this species from all other Cheilosia of the region, except for C. borjomi sp. nov., C. melanopa and C. redi . It is similar to C. melanopa and C. redi but on average larger ( 9–12 mm vs 8–10 mm), with slenderer abdomen, legs all black (base and sometimes apex of tibiae yellow in those of C. melanopa and C. redi ), in the male, the ventral part of the metafemur has black setae (with short black pile in C. melanopa and C. redi ) and in the female, the metatibia has black pile anterolaterally (yellow in that of C. redi ) and scutum with shorter semi-adpressed yellow and black pile and with sparse, longer, more erect black pile (with short erect yellow pile in that of C. melanopa ). It is very similar to C. borjomi ; see Differential diagnosis of that species for differences. Despite small genetic differences with European populations of C. variabilis , no consistent morphological differences were found. The male genitalia of C. variabilis are figured in Francuski et al. (2009).

Material examined

Collected in 2018, 2019, 2021 and 2023; see Mengual et al. (2020) for detailed records from 2018.

Genetics

DNA barcodes of C. variabilis are grouped in one cluster without high support (BS <90%), comprising a group of sequences from European specimens (BS <90%) and another group of sequences with the Caucasian individuals (BS = 95.4%).

Remarks

Some records of C. variabilis in Mengual et al. 2020 actually are C. borjomi sp. nov., and are reported as such in the account of C. borjomi .

Biology

During our expeditions, collected between 30 April and 26 June at an altitude between 751 and 2300 m a.s.l. Often found near forest or shrubs or near tall vegetation in meadows. Males sit on leaves of trees and both sexes visit a variety of flowers, often white umbellifers.

Distribution

Western and Central Palaearctic, into western Siberia. Distribution within the Caucasus difficult to assess because previous records could also be Cheilosia borjomi sp. nov., but reported from Armenia, Georgia and Russia.