Ablabesmyia (Ablabesmyia) monilis

Ablabesmyia (Ablabesmyia) monilis auct nec Linné, 1758.

(Figs 2 F; 3 F; 4 F, M; 5 H; 9 A.–C; 10)

Ablabesmyia (Ablabesmyia) americana Fittkau, 1962: 429; Stur & Ekrem 2011: 46; nomen dubium.

The different stages are illustrated.

Material examined. CANADA: British Columbia, British Columbia, Marion Lake, 7 males, 15–17.vii 1964, 30.iv.–10.vi. and 18.viii. 1965, A. L. Hamilton; Manitoba, Heming Lake, 2 males reared from larvae 11.vi.–27.vi. 1967, A. P. Wiens; Ontario, Kenora, Experimental Lakes Area, Lake 122, male reared from larva, 22.vii. 1968, S. S. Chang; Ontario, Waterloo, male, 13.vi. 1968, C. G. Paterson. Lake Winnipeg records: 2 km off Selkirk (Horse) Island, 1 male, 7.vi. 1969; 4 km off Grand Rapids, 8.vi. 1969; McBeth Harbour, 1 male, 30.vii. 1969; Beaver Point, 1 male; 30.vi. 1971; Old Fishing Dock, 17 males, 8.ix. 1971; Beaver Creek, emergence trap, 7 males, 16.vi. –8.viii. 1971; Calder's Dock, 1 female reared from larva, 11.vi. 1971.

Remarks. Stur and Ekrem (2011: 46) found that analysis of partial COI gene sequences showed differences sufficient to treat A. monilis and A. americana as different species. Roback (1971: 376) found no valid differences between two European specimens of A. monilis and his Nearctic material. His illustrations of the aedeagus (figs. 572–575), however indicates that there may be some difference in the shape and width of blade of the male aedeagus. The seminal capsules of the females are dark in oral half in the Nearctic specimens (Saether 1977 fig. 21A), while according to Stur and Ekrem (2011) they are pale in the Palaearctic specimens. The Nearctic pupae had much stronger and darker veins on the wing pads than the few Palaearctic specimens examined.

Fittkau (1962: 429) proposed “ Ablabesmyia americana n. spec. (= Pentaneura monilis, Johannsen 1905)" as a new species, which satisfies the requirements for availability in ICZN (1999) articles 13.1.1. and 13.1.2. However, according to Roback (1971: 378) Johannsen’s material of “ A. monilis ” consists of at least two species, A. monilis auct nec L. sensu Roback (1971) and A. annulata (Say). Therefore, the type series of A. americana Fittkau became equally mixed and the name a nomen dubium until the type series is examined and a lectotype selected.

Distribution and ecology. The species is widespread in North America (Fittkau et al. 1967: 348, Hudson et al. 1990: 3; Roback 1971: 377, Oliver et al. 1990: 10; Spies 1999; Epler 2003; Ashe & O’Connor 2009: 117). The ecology of A. “ americana ” appear to be the same as that of A. monilis preferring lakes and slow-flowing rivers. Here they live as well in the mud as in the periphyton of stones and between higher vegetation (Fittkau 1962: 440). Brundin (1949: 683) found the larvae in oligohumic, oligotrophic, subarctic lakes as well as in polyhumic bog lakes and strongly eutrophic lakes. A. monilis is littoral in eutrophic lakes, but enters the upper profundal in oligotrophic lakes (Fittkau 1962: 440).