Culicoides griseidorsum Kieffer, 1918

Szadziewski, Ryszard, Filatov, Serhii & Dominiak, Patrycja, 2016, A redescription of Culicoides griseidorsum Kieffer, 1918, with comments on subgeneric position of some European taxa (Diptera: Ceratopogonidae), Zootaxa 4107 (3), pp. 413-422 : 414-417

Culicoides griseidorsum Kieffer, 1918

( Figures 1–3 )

Culicoides griseidorsum Kieffer, 1918: 46 (female); Szadziewski 1984: 166 (female neotype, syn.: = saevanicus sensu Kremer et al. 1973 nec Dzhafarov, 1960; Algeria, Poland, Israel, Great Britain); Heredia et al. 2011: 178 (female, Spain); Talavera et al. 2011: 222 (male, female, Spain, short description); Ayllón et al. 2014: 1 ( Germany, collected on cattle and sheep); Bobeva et al. 2014: 4507 ( Bulgaria); Sarvašová et al. 2014: 547 (female, male, Slovakia).

Diagnosis. In both sexes wing with distinct pale spots, apex of second radial cell pale ( Figs. 1 a–b, 2a–b), sensory pit of the third palpal segment shallow, usually with irregular borders, and terminal flagellomere lacking sensilla coeloconica ringed with microtrichia. Female with sensilla coeloconica present on flagellomeres 1–12, two subequal, ovoid functional seminal capsules present. In male genitalia gonocoxite with slender and simple ventral apodeme, parameres bare, with distal portion slender, pointed and strongly bent, caudomedian excavation of sternite 9 with microtrichia.

Description. Male (n=8). Body brownish with yellowish scutellum and paler legs. Eyes bare. Flagellum length 0.840–0.870 mm; antennal ratio (AR) 0.65–0.68. Flagellomeres 2–10 fused, Sensilla coeloconica ringed with microtrichia distributed as follows: 1(2), 2(0–1), 3–7(0), 8(0–1), 9–10(0), 11(1–2), 12(4–5), 13(0). Distal flagellomeres 11–13 bearing sensilla basiconica distributed as follows: 11(4), 12(4), 13(8). Blunt tipped sensilla trichodea absent. Flagellomeres 1–10 with long plume setae; first flagellomere with two rings of plume setae; flagellomeres 11 and 12 each with 6 sensilla chaetica; terminal flagellomere with single apical sensillum chaeticum. Palpus 5-segmented. Third palpal segment slender with shallow, indistinct sensory pit ( Fig. 3 a); length 0.060–0.065 mm. Wing length 1.25–1.44 mm, costal ratio (CR) 0.53–0.55, membrane including basal radial cell with some macrotrichia, apex of second radial cell pale; distal half of wing with 4 pale spots in transverse row behind second radial cell, and 3 pale spots along wing apex ( Figs. 1 a–b). Tibial comb with 4 spines. Tarsal ratio of hind leg TR (III) 1.61–1.85. Claws with forked apex. Male genitalia as in Figs. 3 b–e. Sternite 9 with broad and shallow caudomedian excavation, membrane covered with small spicules (microtrichia). Tergite 9 with long triangular apicolateral processes. Gonocoxite without modifications, ventral apodeme triangular, with pointed apex. Gonostylus almost straight, simple, with enlarged basal half. Aedeagus Y-shaped, basal arch high, caudomedian portion subcylindrical, with blunt apex. Parameres separate, bare, tapering to pointed apex, distal portion strongly bent ( Figs. 3 c–e).

Female (n=12). Similar to male with usual sexual differences. Flagellum 0.580–0.705 mm long, AR 1.11–1.18, sensilla coeloconica ringed with microtrichia (16–17) usually present on flagellomeres 1–12, their distribution as follows: 1(4), 2–11(0–1), 12(2–3), 13(0); sometimes absent on left or right one or two flagellomeres. Terminal flagellomere 13 always without sensilla coeloconica ringed with microtrichia. Distal flagellomeres 9–11 with 4 sensilla basiconica, flagellomeres 12–13 with 6. Proximal flagellomeres 1–8 with 3–4 long to moderately short sharp tipped sensilla trichoidea (trichodea). Blunt tipped sensilla trichoidea absent. Sensory pit on third palpal segment broad and shallow, proximal margin strongly sclerotized and irregular, distal margin usually not developed. Eyes bare, narrowly separated. Scutellum pale. Wing dark with large pale spots ( Fig. 2 a–b). Apex of second radial cell pale. Membrane including basal radial cell covered with macrotrichia. Wing length 1.25–1.43 mm, CR 0.56–0.60. Two subequal subspherical seminal capsules present, both without neck ( Fig. 3 f); bigger seminal capsule 1.15 times longer (0.0475 mm) than the smaller one (0.0413 mm). One specimen examined with three well-developed seminal capsules ( Fig. 3 g).

Material examined. Algeria: Aokas near Béjaia, 6 May 1981, neotype female Culicoides griseidorsum Kieffer, 1918 , leg. R. Szadziewski. Poland: Ustrzyki Górne, Bieszczady Mts, 23–30 July 1980, sweeping, 1 female, leg. R. Szadziewski. Ukraine: Kharkiv region, Bliznyuki, 48o42’4.2”N, 36o36’19”E, light trap, 21/ 22 May 2013, 8 males, 7 females; same data, 3/ 4 July 2013, 3 females, leg. S. Filatov.

Distribution. Algeria, Tunisia, Israel, Spain, Italy, France, Bulgaria, Germany, Greece, England, Slovakia, Poland. Recorded for the first time from Ukraine.

Systematics. For a long time C. griseidorsum has been known from female specimens only. Talavera et al. (2011) and Sarvašová et al. (2011) were the first authors to identify and briefly diagnose males from Spain and Slovakia respectively. The present paper provides a detailed description of both sexes and illustrates the male for the first time.

Culicoides griseidorsum is remarkably similar to some other species of the Pictipennis group, as has been already noticed by various authors ( Szadziewski 1984, Talavera et al. 2011, Bobeva et al. 2014). Perhaps the most well recognized confusion over its taxonomic status relates to erroneous synonymization of the species with C. saevanicus Dzhafarov, 1960 and it is attributable to insufficient descriptions of both species. While in the older literature C. griseidorsum from Western Mediterranean is reported as C. saevanicus ( Kremer et al. 1973, Mellor et al. 1983, 1984) and subsequently the latter name was sometimes treated as a junior synonym of C. griseidorsum (Braverman et al. 1996, Borkent & Wirth, 1997, Talavera et al., 2011), these two species are not conspecific, as has been convincingly shown by Szadziewski (1984) and Glukhova (1989, 2005). Glukhova in her monograph on the Soviet Union Culicoides published in 1989 designated the lectotype male and paralectotype female for C. saevanicus Dzhafarov. According to the redescription, wing pattern is almost the same as in C. griseidorsum , however all flagellomeres bearing sensilla coeloconica, spermathecae are equal and distal portion of parameres in male genitalia are stout, almost straight and blunt, caudomedian excavation of sternite 9 is bare, without microtrichia. Moreover, ventral apodeme of gonocoxite is totally reduced.

Using a key to males by Glukhova (2005) (p. 17) males of C. griseidorsum fall to the couplet 86(85) together with C. subgrisescens . The latter species differs in having much stouter parameres, distal half of second radial cell pale, and terminal flagellomere with sensilla coeloconica ringed with microtrichia. Similarly, using the key for females of Oecacta with spotted wings ( Glukhova 2005) (p. 13) females of C. griseidorsum fall to the couplet 10(15) together with C. pictipennis , C. ustinovi , C. subgrisescens and C. saevanicus . Females of these four species differ in having sensilla coeloconica on all 1–13 flagellomeres and sensory pit with distinct and regular margin, while C. griseidorsum has no sensilla coeloconica on terminal flagellomere 13 and shallow sensory pit with irregular border. Terminal flagellomere 13 without, and flagellomeres 1–12 with sensilla coeloconica are present in females of C. zhogolevi Remm, 1968 . However the latter species has wing with much smaller pale spots, second radial cell completely dark and palpus with distinct sensory pit. Moreover, the caudomedian excavation of male sternite 9 is bare in C. zhogolevi .

Remarks. It is worth mentioning that among the specimens examined, a female with three functional seminal capsules was found. It is quite a common situation that in some Culicoides species characterized by having one rudimentary and two functional seminal capsules, the rudimentary one has actually become normally developed. In Poland, for example, this is most often observed in females of C. pallidicornis Kieffer (present observation). The presence of three well-developed functional spermathecae is confusing and may lead to incorrect identification and the subgeneric placement of the specimens. That is why such atypical specimens from Romania were included in the subgenus Trithecoides Wirth & Hubert ( C. humeralis Okada, 1941 in Damian Georgescu 2000 , p. 48), or even new subgenera were proposed for Chinese Culicoides , viz. Sinocoides Chu, 1983 (type species C. hamiensis Chu et al. 1982 ) or Jilinocoides Chu, 1983 (type species C. dunhuaensis Chu, 1983 ) ( Chu 1983).

Figures

FIGURE 1. Culicoides griseidorsum Kieffer, 1918. Male wing: a. bright field image; b. dark field image.

FIGURE 2. Culicoides griseidorsum Kieffer, 1918. Female wing: a. bright field image; b. dark field image.

FIGURE 3. Culicoides griseidorsum Kieffer, 1918. Male (a – e), female (f – g): a. maxillary palp; b. genitalia, ventral view; c – e. parameres, ventral view; f – g. seminal capsules.