Diamesa leona Roback 1957

Diamesa leona Roback

(Figs. 29–46)

Diamesa leona Roback, 1957: 7, 1959: 2; Hansen & Cook 1976: 106; Makarchenko 1981: 103, 1985: 73, 2006: 262; Herrmann et al. 1987: 311; Linevich & Makarchenko 1989: 30; Ashe & O’Connor 2009: 280.

Diamesa pieta Roback, 1957: 8.

Diamesa caena Roback, 1957: 9.

Diamesa breviala Tokunaga, 1964: 39.

Diamesa renegata Makarchenko, 1977: 1732.

Diamesa mongolica Serra-Tosio, 1983: 11.

Diamesa starmachi Kownacki et Kownacka, 1970: 777; Spies & Saether 2004: 19 (name correction); Ashe & O’Connor 2009:

285; Giłka et al. 2013: 202; Rossaro & Lencioni 2015: 70. Syn. nov.

Material examined. RUSSIA: 5 adult males, 3 females, Primorye Territory, Khasansk District, Kedrovaya Pad Nature Reserve, Kedrovaya River, 12.II.1977, leg. E. Nikolayeva; 1 adult male, the same data except 10.II.1979, leg. Yu. Shibnev; 1 mature pupa, the same data except 8.II.1980, leg. E. Makarchenko; 2 adult males, the same data except 19. III.2016, leg. E. Makarchenko; 2 adult females, the same data except 23.II.2019, leg. E. Makarchenko; 3 adult males, the same data except Ussuryiskyi District, Ussuryisky Nature Reserve, 1. XII.1972, leg. I. Chereshnev, L. Budnikova; 1 adult male, the same data except Chuguevskyi District, Elovyi Stream, 31. V.1977, leg. T. Vshivkova; 1 adult male, the same data except Partizanskyi District, Tigrovaya River, 10. V.2020, leg. E. Gorovaya; 4 adult males, the same data except Khabarovsk Territory, Nanaisky District, Anyuisky National Park, Pihtsa River (tributary of Gassi Lake), Amur River basin, N 48.47.804, E 136.47.027, 22–24. V. 2019, leg. N. Yavorskaya; 1 adult male, the same data except Solnechnyi District, Gornyi Village, Silinka River (Amur River basin), 26. VII.1983, leg. E. Makarchenko; 1 adult male, 1 female, the same data except Magadan Region, Tenkinskyi District, not far from Sibit-Tyellakh Village, Ozernyi Stream (Kolyma River basin), 3. VI.1978, S. Kocharina; 2 adult males, the same data except Khasynskyi District, Khasyn River, (Arman River basin) not far from Khasyn Village, 30. VI.2017, leg. I. Zasypkina; 2 adult females, the same data except Olskyi District, Ola River (upper stream), 1. V.2016, leg. E. Khamenkova; 1 adult male, 1 female, the same data except 3. V.2019, leg. E. Khamenkova; 3 adult males, the same data except Kamchatka Territory, Avacha River, 14. VI.1970, leg. V. Levanidov; 4 adult males, the same data except Sakhalin Island, Forest Park of Yuzhno-Sakhalinsk City, Rogatka River, 15. V.1984, leg. E. Makarchenko; 2 adult males, the same data except Krasnoselskaya River near Novoalekseevka Village, 2. VI.1984, leg. E. Makarchenko; 10 adult males, the same data except Chukotka Peninsula, Yoni Lake basin, Gilmimliveem River, 4. VIII.1973, leg. I. Chereshnev; 2 adult males, the same data except Chegitun River, middle stream, 4. VIII.1981, leg. Makarchenko. KAZAKHSTAN: 2 adult males, East Kazakhstan region, Katon-Karagai District, Sarymsaqty Mountains (Kazakh Mountain Altai), Arasan River, about 0.7 km below of Bolshoe Rakhmanovskoye Lake, altitude 1790 m above sea level, 5. VII.2018, 49.535983 N, 86.500633 E, leg. D. Palatov.

Comments. The species D. leona, D. pieta and D. caena were described from North America by Roback (1957) from adult males collected in the same area but at different times. The first two species differed from each other mainly in color and D. caena in reduced wings and the “absence” of the anal point. Hansen (Hansen & Cook1976) comparing the type material of these species, came to the conclusion that D. pieta and D. caena should be junior synonyms of D. leona since all specimens have an anal point and wing reduction is not a diagnostic feature (Hansen & Cook 1976). D. breviala Tokunaga from Japan (Tokunaga 1964) and D. renegata Makarchenko from the Russian Far East (Makarchenko 1977) with reduced wings also were described as adults males. As a result of studying additional material from various regions of the Far East, we came to the conclusion that these both species are identical to the North American D. leona, since have similar hypopygium and occur in populations with both brachypterous and macropterous specimens (Makarchenko 1981). We subscribe to the opinion of SerraTosio (1974) and Hansen & Cook (1976) that the brachypterism of the genus Diamesa is not a basis for taxonomic identification. In the meanwhile it was suggested that D. starmachi Kownacki et Kownacka from the Polish Tatras (Kownacki & Kownacka 1970; Giłka et al 2013) may be also a junior synonym of D. leona, since it has a similar structures of the hypopygium. But it became possible to confirm this only now, after obtaining the molecular genetic data of these two species. DNA-based methods significantly complement traditional taxonomic approaches in that they facilitate to differentiate closely related species or reveal the presence of distinct taxa that are morphologically indistinguishable. The results of DNA barcoding made it possible to confirm conspecificity of D. starmachi from Norway (HQ941609) and D. leona from Kazakhstan and Russia (ON834735 – ON834742). Phylogenetic analysis has shown that the identity of D. starmachi can no more be supported and it is here stated that D. starmachi is a junior synonym of D. leona.

Since it’s hard to make a general description for the brachypterous and macropterous forms of males from different regions of the Holarctic and to combine all the data available in the literature, we decided to present the main features of these forms in the Table 10 and give a description of hypopygium only.

Description

Adult male. Hypopygium (Figs. 29–46). Large, usually darker than body segments, heavily chitinized and curved dorsally. Tergite IX with delicate pubescence of microtrichia directed anteriorly; anal point in brachypterous forms 42–80 μm long and 55–108 μm long in macropterous forms, directed downwards at an angle (Fig. 35), almost invisible from above; on straightened tergite IX, viewed from above, anal point often with cut top (Figs. 32–34, 42– 42, 45) (more often in brachypterous forms) or rounded top (Figs. 34, 46), sometimes with sharp top and completely covered with microtrichia (Fig. 40), while in most cases the subapical part of the anal point without microtrichia; gonocoxite long, broad, with numerous short, anteriorly-directed setae (Figs. 29, 41–44, 46); gonostylus strong, slightly curved, with numerous short, proximally directed setae; medial surface of gonostylus with fine “pile” of microtrichia, with large terminal spine at end, subterminal setae absent (Figs. 30, 34, 36–39, 41–44, 46). Transverse sternapodeme very strong, triangular, produced to a point antero-medially (Figs. 39, 42–44). Anal point length/ gonostylus length 0.13–0.37). HR 1.50–2.47.

In the process of studying the material from Sakhalin Island several abnormal males were found that lacked the anal point and the posterior margin of tergite IX was concave in the middle (Fig. 31).

Pupa (as D. starmachi) was described by Kownacki & Kownacka (1970) and Makarchenko (1981).

Larva was described by Rossaro & Lencioni (2015).

Biology. The biology of D. leona is very interesting because adult males and females can lead an active life under extreme conditions, namely low air temperatures in winter time. Quite a lot has been published about this for specimens living in North America (Hansen & Cook 1976, Herrmann et al. 1987) and the Polish Tatras (Giłka et al. 2013). But there is very little information about this from the Russian Far East. Therefore, below we present some data on the biology of D. leona from this region of the Palaearctic.

In the south of the Russian Far East the species is apparently bivoltine, in the Northeast it is univoltine. Males and females of the first generation in Primorye Territory are brachypterous; they hatch from pupae from early December to early March at a water temperature in the river from 0.1 to 1.5ºC., and air temperature from –21ºC to +5ºC. The maximum emergence of adults occurs in mid February. Once three brachypterous males were collected in the Ussuriysky Nature Reserve in the snow on December 1, 1972 at an air temperature of—21ºC. Adult insects of the first generation are more like spiders than chironomids. Due to the strong development of the legs, they move well on the ice and are often found on the snow. Males and females of the second generation are macropterous; their emergence occurs in the same area from the end of May to the first half of June. We also encountered brachypterous specimens in the mountains of the Upper Kolyma River basin in early June and in South Sakhalin in the first half of May. Macropterous specimens in South Sakhalin were collected from early May to early June at a water temperature in the rivers from 4 to 17ºC. On the Chukotka Peninsula the emergence of adults was observed from the second half of July to mid August, in Kamchatka —in mid June. In the Chukotka Peninsula and Kamchatka males and females of D. leona were collected only as macropterous. But despite well developed wings they do not fly and like brachypterous form sit mainly under damp stones along the banks of watercourses. This is where mating takes place. The inability to fly in macropterous specimens is apparently associated with the underdevelopment of the flight muscles. Larvae and pupae live in foothill and mountain streams on stones with a fast current. On Sakhalin Island the largest number of pupae and larvae was observed among algae Hydrurus foetidus Kirchn. D. leona reaches its highest altitude (about 800 m) in the Upper Kolyma River basin.

Distribution. Widespread arcto-alpine Holarctic species. Known in North America from Canada (New Brunswick and Quebec) and U.S.A. (Colorado, Idaho, Vichigan, Minnesota, Montana, Nevada, New Mexico, Utah, Washington and Wisconsin). In the Palaearctic recorded from China, Japan, Mongolia, Poland, Austria, Germany, Italy, Luxemburg, Slovakia, East Siberia, Russian Far East (Ashe & O’Connor 2009) and Norway.