Cheilosia (Cheilosia) bergenstammi Becker, 1894

Prokhorov, A. V., Popov, G. V., Shparyk, V. Yu. & Vasilyeva, Yu. S., 2020, New Records Of Hoverflies (Diptera, Syrphidae) From Ukraine. V, Zoodiversity 54 (3), pp. 237-258 : 238-240

Cheilosia (Cheilosia) bergenstammi Becker, 1894 ( figs 1–8 )

M a t e r i a l e x a m i n e d. Ukraine. Volyn Region: Kholopychi env., 50.808819 N 24.749204 E, 16.07.2019, 1 {( V. Kavurka) ; Rivne Region: Bushcha env.: 50.295 N 26.284 E, Zbytynka River floodplain, 11.05.2018, 1 {; Myzotskyi Kriazh, 50.30 N 26.30 E, deciduous forest, 17.05.2019, 1 {(A. Prokhorov) .

D i s t r i b u t i o n: Austria, Belarus, Belgium, Bosnia and Herzegovina, the Czech Republic, Denmark, France, Germany, Great Britain, Hungary, Ireland, Italy, Latvia, Liechtenstein, Luxembourg, Montenegro, the Netherlands, Norway, Poland, Romania, southern European Russia, Serbia, the Slovak Republic, Northern Spain, Sweden, Switzerland; Transcaucasia (the Republic of Georgia) ( Bańkowska, 1963; Peck, 1988; Kuznetzov, 1993; Verlinden, 1991; Maibach et al., 1992; Dirickx, 1994; Belcari et al., 1995; Vujić, 1996; Holinka & Mazánek, 1997; Wolff, 1998; Nielsen, 1999; Carrières, 2001a; Stubbs & Falk, 2002; Stănescu & Pârvu, 2005; Mielczarek, 2009 –2020; Reemer et al., 2009; Tóth, 2011; Borodin & Borodina, 2014; Ricarte & Marcos-García, 2017; Barkalov & Mutin, 2018; Speight et al., 2018; Mengual et al., 2020; Speight, 2020; Wakkie, 2020); Ukraine (first record).

D i a g n o s i s. Cheilosia bergenstammi belongs to the species group D of Cheilosia (sensu Becker, 1894) , which is characterized by the compound eye pilose (entirely or partly), lower part of face without pile, legs with yellow (at least tibiae yellow on both sides), posterior edge of scutellum with pile and setae. The male of C. bergenstammi is most similar to C. fraterna (Meigen, 1830) ( figs 9–16 ), and somewhat similar to C. carbonaria Egger, 1860 , C. cynocephala Loew, 1840 , C. sootryeni Nielsen, 1970 , and C. vernalis (Fallén, 1817) in having facial width (just below antennal sockets) not exceeding eye width at the same level, katepisternum with upper and lower patches of pile widely separated, at least tibiae with pale parts, hind femur ventrally with numerous thick setae, and hypopygium with pale pile. Cheilosia bergenstammi differs from the last four species by: compound eye with yellowish or light brown pile, at the lower part of eye without pile ( figs 6–8 ) (in others, eye entirely covered in dark pile, except C. sootryeni with light brown pile and lower part of eye almost bare); fore and mid tarsi with tarsomeres 1–3 yellow ( figs 4, 5 ), at most first tarsomere of the fore tarsus may be darkened dorsally (in others, fore and mid tarsi entirely black; in C. vernalis , first tarsomere (rarely tarsomere 2 also) of mid leg may be yellow or brownish, sometimes only at the base); tergites 2 and 3 with only pale and mostly erect pile (in others, at least tergite 3 and usually tergite 2 with a central patch of black pile or seta-shaped macrotrichia, which are often adpressed or semi-adpressed).

Cheilosia bergenstammi also differs from C. carbonaria by: abdomen elongated-oval with almost parallel sides of tergite 3 (in C. carbonaria , abdomen elongated, expanding to posterior margin of tergite 3, with the largest width in this place); wing hyaline with yellowish tint ( fig. 1 ) (in C. carbonaria , wing distinctly darkened along the front edge and in the middle); hind tibia with distinct black ring occupying almost half of the tibia ( fig. 3 ) (in C. carbonaria , hind tibia almost black with only brownish base).

Cheilosia bergenstammi also differs from C. cynocephala by: mesonotum black with bronze tinge (in C. cynocephala , mesonotum black with bluish tinge); tibiae yellow with black ring occupying not more than half of the tibia ( fig. 2 ) (in C. cynocephala , tibiae with black ring occupying usually more than half of the tibia); mesopleura with pale pile (in C. cynocephala , mesopleura with pale and black pile mixed).

Cheilosia bergenstammi also differs from C. sootryeni by: tibiae with yellow apex occupying not less than 1/4 of the tibia ( fig. 2 ) (in C. sootryeni , tibiae with yellow apex occupying not more than 1/8–1/6 length of the tibia); mesopleura with pale pile (in C. sootryeni , mesopleura with pale and black pile mixed).

Cheilosia bergenstammi also differs from C. vernalis by: lower part of face more elongated, so that the facial tubercle usually extends beyond first flagellomere (basoflagellomere) (in C. vernalis , lower part of face less elongated, so that the facial tubercle doesn’t extend beyond the first flagellomere). Unfortunately, C. vernalis is one of the most variable species of the genus, and listed characters may be completely different.

The Cheilosia bergenstammi male is also similar to the male of C. fraterna ( figs 9–16 ), in addition to the above characters, in having compound eye with lower part bare, wing hyaline with yellowish tint, and tergites 2 and 3 with only pale pile. From C. fraterna it can be separated by: scutellum with pile and setae at least as long as scutellum ( fig. 2 ) (in C. fraterna , scutellum with pile and setae half or slightly more than half as long as scutellum ( fig. 10 ), scutellum often without setae); abdomen elongated-oval with almost parallel sides of tergite 3 ( fig. 1 ) (in C. fraterna , abdomen wide oval, distinctly with largest width at the posterior edge of tergite 2, as in fig. 9 ); fore and mid tarsi with tarsomeres 1–3 pale ( figs 4, 5 ), at most first tarsomere of the fore tarsus darkened dorsally (in C. fraterna , fore tarsus black dorsally ( fig. 12 ) with at least tarsomeres 1+2 pale laterally, mid tarsus ( fig. 13 ) with first tarsomere usually pale and tarsomeres 2–5 darkened dorsally); hind tibia ( fig. 3 ) with distinct black ring occupying almost half of tibia (in C. fraterna , hind tibia with weak, incompletely developed dark ring ( fig. 11 ), which may be reduced).

Genitalia of C. bergenstammi have been prepared and compared with figures in Stubbs & Falk (2002: Plate H, fig. 1 , a–c) and Barkalov (1993: figs 156–158).

Figures

Figs 1–8. Cheilosia bergenstammi male: 1 — habitus, dorsal view; 2 — habitus, lateral view; 3 — hind femur and tibia, lateral view; 4 — fore tarsus, dorsal view; 5 — mid tarsus, dorsal view; 6 — head, anterolateral view; 7 — head, frontal view; 8 — head, lateral view.

Figs 9–16. Cheilosia fraterna male: 9 — habitus, dorsal view; 10 — habitus, lateral view; 11 — hind femur and tibia, lateral view; 12 — fore tarsus, dorsal view; 13 — mid tarsus, dorsal view; 14 — head, anterolateral view; 15 — head, frontal view; 16 — head, lateral view.