Cheilosia ( Cheilosia ) mutabilis ( Fallén, 1817 )

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 : 93-95

Cheilosia ( Cheilosia) mutabilis ( Fallén, 1817)

Fig. 47

Eristalis mutabilis Fallén, 1817: 54 .

Syrphus ruralis Meigen, 1822: 293 . Syn. by Claussen & Speight (1999).

Cheilosia mutabilis – Radde 1899: 453. — Stackelberg & Richter 1968: 247. — Tóth 1986: 94. — Stackelberg 1970: 62. — Peck 1988: 109. — Barkalov 1993: 712. — Gujabidze 2002: 246. — Barkalov & Mutin 2018: 483. — Mengual et al. 2020: 19.

Cheilosia ruralis – Stackelberg & Richter 1968: 248. — Stackelberg 1970: 64. — Barkalov 1993: 721. — Gujabidze 2002: 246.

Cheilosia ruralis Meigen, 1822 [sic] – Gujabidze 2002: 246.

Differential diagnosis

Cheilosia mutabilis is a small (body size 7–8.5 mm) and slender species, easily confused with C. urbana and C. psilophthalma . Best distinguished from those by the black metaleg, with only base of metatibia yellow ( Fig. 47A) (in the other two the metatibia with distinct orange base and apex) and arista with long pilosity, longer than or almost equal to the width of arista at base (in the other two species shorter than the width of arista at base).

Material examined

Collected in 2018, 2019, 2021, 2022 and 2023; see Mengual et al. (2020) for detailed records from 2018.

Genetics

All DNA barcodes of C. mutabilis from Europe and Caucasus are grouped together with high support (BS = 100%). Within the group there are two clusters and a single male from France. The two clusters differ morphologically, for instance, the specimens in the cluster in which the Armenian specimens are, are larger (body size on average 8.5 mm vs 7–7.5 mm), the face is wider, the parafacia is wider and the facial tubercle is better developed. However, all these differences appear to be subtle or overlapping, so for now we leave them as one species, but future research, with sampling in a larger range, could give more insight in the relations of these clusters.

Remarks

Claussen & Speight (1999) synonymized Syrphus ruralis Meigen, 1822 with C. mutabilis .

Biology

During our expeditions, collected between 9 May and 3 August at an altitude between 840 and 2500 m a.s.l.

Distribution

Western and Central Palaearctic, into western Siberia. Armenia, Georgia.