Bradysia forficulata (Bezzi, 1914)

Babytskiy, A. I., Rubanovska, N. V. & Bezsmertna, O. O., 2022, New Records Of Sciarid Species (Diptera, Sciaridae) From Ukraine. Iv, Zoodiversity 56 (6), pp. 435-446 : 436-438

Bradysia forficulata (Bezzi, 1914) ( figs 1–3 )

M a t e r i a l e x a m i n e d. Ukraine, Kyiv Region: Kyiv City, Koncha-Zaspa District, Holosiivskyi National Nature Park , 50.24597° N, 30.62059° E, ca. 100 m a. s. l., pine forest, sweeping, 09.04.2017, 1 Ơ (A. Babytskiy) (No. 158, UkrBIN-795857) .

D i s t r i b u t i o n: Cosmopolitan. In Palaearctic is common and widely distributed in Europe: Austria, Belarus, Belgium, Bosnia and Herzegovina, Czech Republic, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Luxembourg, the Netherlands, Norway, Poland, Russia (European territory), Spain (mainland), Sweden, Switzerland, Ukraine (first record), United Kingdom. In Nearctic known from North America: Canada (Alberta, British Columbia), USA (Arizona, California, Georgia, Tennessee, Texas, Virginia). Outside Holarctic region only recorded from Gough Island ( Gerbachevskaja-Pavluchenko, 1986; Menzel et al., 2013; Mohrig et al., 2013; Heller & Menzel, 2017; GBIF, 2022 a; this study).

Diagnosis. Male adults reach 4–5 mm in length. Head dark brown. Ocelli in a flattened triangle behind the eye bridge and separated from it by a distance greater than two diameters of the eye bridge. Eye bridge consists of 2–3 rows of ommatidia (facets), however middle ommatidia (a pair on each side) are not quite touching. Face dark brown with pale setae. Maxillary palpus brownish, 3-segmented. Basal palpal segment club shaped with sensory pit and several bristles, one of them longer. Sensory pit round, deepened, distinctly marginated and dark. Middle palpal segment oval with several bristles, one of them longer. Terminal palpal segment narrow, twice as long as the 2nd segment. Antennae dark brown. Flagellum very long, reach 2.0– 2.2 mm in length. Flagellomeres with short necks and setae quite longer than a half of flagellomeres width. The 4th flagellomere up to 5.0 times as long as wide (obviously, in the previous descriptions this measure includes the neck and body), length/width of 4th flagellomere of Ukrainian specimen = 3.5, with a basal node index of 2.51. Thorax with black sclerites. Anterior pronotum and prothoracic episternum with about 10 fine setae each. Mesonotum with pale brown setosity. Scutum with two irregular rows of acrostichal setae which extending the length of the scutum; acrostichal and dorsocentral setae black and short. Scutellum with 6 long bristles and several minor setae. Wing hyaline, 2.8–3.1 mm long and 1.2 mm wide, width/length of wing = 0.37–0.38. Membrane hyaline. M-fork narrow, stM indistinct, as long as M

1

; stM/Mfork = 0.87–0.91; R 1 = R, R 1 long, falls into C opposite or very slightly proximad of the M-fork base, R 1 /R of Ukrainian specimen = 1.03–1.04; y longer than x, with 2–3 macrotrichia, x bare, x/y = 0.77–0.97; CuA 1 slightly dented in the middle; CuA 2 smoothly arched; stCuA well recognizable, makes 0.66–1.00 x, stCuA/x of Ukrainian specimen = 0.61–0.85; c = 0.66 w, c/w of Ukrainian specimen = 0.75–0.77. Halter pale brown to yellow, with 10–15 black strong setae. Legs. Forelegs yellowish except only brown very base of fore coxae. Hindlegs pale brown with brown tarsus; hindtarsus black-brown from apical half of hindmetatarsus. Hindfemur = 1.1 mm; hindtibia = 1.4–1.5 mm; hindmetatarsus = 0.72 mm; hindtarsus = 1.55 mm. Trochanters blackened. Tibial organ of p 1 with yellowish long comb-like row of bristles ( fig. 3 ). Meso- and hindtibia with two yellow spurs, which are a little longer than the diameter of the tibiae at the tip. Length of spur/width of tibia: p 1 = 1.30–1.32, p 2 = 1.62– 1.77, p 3 = 1.59–1.60. Length of metatarsus/length of tibia: p 1 = 0.54–0.58, p 2 = 0.58–0.59, p 3 = 0.51–0.54. Tarsal claws small, without teeth. Abdomen brown, paler than thorax, with not rather short brownish setosity. Hypopygium ( fig. 1 ) black-brown. Intergonocoxal area without differentiation or bristle group, only with short setae. Gonostylus ( fig. 2 ) slightly clubby at the tip with a curved apical tooth, and thorny subapical setae basad of the tooth on the medial side of gonostylus reach its middle; gonostylar tip densely setose. Tegmen with subconical rounded apex and strongly sclerotised base. Aedeagus fairly long. Area of teeth narrow, teeth single-pointed ( Johannsen, 1929; Tuomikoski, 1960; Mohrig & Menzel, 1993).

Bradysia forficulata belongs to the B. pallipes group which includes 36 Palaearctic species, of which 6 are known only from the females. This species differs from the other species groups of Bradysia by the apically wide rounded, non-narrowed to pointed gonostylus with apical dark, dense, fur-like setae and a dense subapical group of spinose setae or short spines; medial side of gonocoxite often with long, strong setae that often extend to middle of genitalia and with 2 dense groups of setae on basal corner or with a group of strong setae or a lobe-like procession on inner membrane; sensory area on basal palpal segment with distinct margin in a deep pit; R and R 1 veins are usually long, joining C almost opposite or only slightly before the base of M-fork ( Menzel & Mohrig, 2000; Menzel & Heller, 2005). From the related species in this group, B. forficulata differs by the presence of only short setae on the intergonocoxal area, but the absence of the other differentiation or bristle groups on the ventral base of gonocoxite, and very long antenna in the cave-inhabiting form. Bradysia forficulata is similar to B. pallipes (Fabricius, 1787) in the structures of hypopygium, but differs by the width/length index of 4th flagellomere (in B. pallipes up to 2.8) and the body size ( B. pallipes = 3.0– 3.5 mm).

Note. Mohrig et al. (2013) stated that B. forficulata occurs in caves, woodlands, and agricultural habitats, and is also common in larger Central European caves. The caveinhabiting form has unusually long flagellomeres in both sexes (4th flagellomere up to 5.0 times as long as wide), and the typical shape of male gonostylus ( Mohrig et al., 2013). Johannsen (1929) also indicated that the cave specimens from Luray Cavern demonstrated antenna elongation: antenna length of specimens studied by him was about 0.8 of the wing length ( Johannsen, 1929). In the other hand, the specimens described by Tuomikoski (1960) as ‘ Bradysia nocturna ’ collected not in caves were characterized by distinctly shorter flagellomeres in both sexes (4th male flagellomere 3.0 times as long as wide). This tendency of extremities elongation of insects living in caves Mohrig with co-authors connected with darkness influence ( Mohrig & Menzel, 1993; Mohrig et al., 2013). The Ukrainian male represents the ‘ B. nocturna type’ of Bradysia forficulata , which was collected in open area in the pine forest by sweeping over grasses and rotten pine trunks. Its antennae are not so long as those of the cave type, and has a similar width/length index of 4th flagellomere as described by Tuomikoski (1960).

Figures

Figs 1–3. Bradysia forficulata Ơ: 1 — hypopygium, ventral view; 2 — gonostylus, ventral view; 3 — anterior apex of fore tibia (p1) with tibial organ, prolateral view. Scale 0.1 mm.