Cerodontha (Xenophytomyza) biseta Hendel

Cerodontha (Xenophytomyza) biseta (Hendel) (Figs. 1–3, 7)

Dizygomyza biseta Hendel, 1920: 135.

Cerodonta uniformis Hering, 1926: 223 –224.

Cerodonta biseta, Hendel, 1927: 254.

Dizygomyza (Poemyza) crassinervis Frey, 1946: 47. Cerodonta (Xenophytomyza) biseta: Frey 1946: 51. Cerodontha (Xenophytomyza) biseta: Nowakowski 1967: 655.

Recognition.­ Cerodontha (Xenophytomyza) biseta has been recently redescribed and/or illustrated by Nowakowski (1973), Spencer (1976) and Zlobin (1993). The phallus of this species has a pale membranous distal process that has been omitted in older papers and was illustrated for the first time by Zlobin (1993). The phallus of the Jamaican specimen of C. (X.) biseta is identical to the European and Nearctic specimens (Figs. 1–2). Although generally described as a completely black or brown species, the inner margin of the orbits, the frons and gena of C. (X.) biseta are sometimes yellowish­brown.

Distribution.­ Cerodontha (Xenophytomyza) biseta (Hendel) is a widespread western Palearctic species that was first recorded in the Nearctic region by Tschirnhaus (1993), based on a few specimens from Ontario and New Brunswick, Canada. This species is apparently expanding its range in eastern Canada and the northeastern United States and has been collected in most eastern Nearctic localities sampled by Lyman Entomological Museum staff and students since 2000. The single specimen of C. (X.) biseta collected from the Jamaican Blue Mountains (Fig. 7) represents the first Neotropical record of Xenophytomyza. All subgenera of Cerodontha have now been recorded in the Neotropical Region except for the Holarctic subgenus Phytagromyza Hendel.

Host plants.­ Two host plants have so far been recorded for this species. Tschirnhaus (1991) collected C. (X.) biseta from emergence traps set up over the grasses Poa nemoralis L. and Holcus lanatus L. in Germany. Many specimens of C. (X.) biseta were also swept from Poa nemoralis in Ottawa, Canada by J.R. Vockeroth (Tschirnhaus, 1993).

Remarks.­ Based on its known distribution (Fig. 7) and its abundance in recent collecting, C. (X.) biseta was probably introduced to North America by human activity, like other Diptera with similar patterns of distribution and abundance (Wheeler et al. 1999). The same assumption could probably be applied to the Jamaican specimen, which was collected in a disturbed agricultural area near a coffee plantation and guest house (T.A. Wheeler, pers. comm.). The alternative hypothesis that C. (X.) biseta in Jamaica represents a native, relict population is less likely as this species has never been collected in other high elevation areas of the Caribbean, Central America or southeastern North America. Because only one specimen has been recorded in Jamaica, the definitive establishment of this species cannot be confirmed until more specimens are collected.

Material examined.­ CANADA: New Brunswick: Charlotte County, Oak Bay, 16– 21.vii.1992, J.E. O’Hara, Malaise (2M, LEM); Doakstown picnic area (46°32.7’N, 66°09.5’W), sweep along small stream on steep hillside, 17.vii.2002, J. Forrest & T. Wheeler (1M, 1F, LEM); Kouchibouguac N.P. 6.vii.1977, J.F. McAlpine (3M, CNC); same except 12.vii.1977 (1F, CNC); same except 13.vii.1977 (6F, CNC); same except 9.vii.1977 (3M, 1F, 2?, CNC); same except J.R. Vockeroth 9.vii.1977 (1M, CNC); Mactaquac Prov. Park (44°57.2’N, 66°53’W), sweep sedges in forest near lake, 16.vii.2002, T.A. Wheeler (2M, LEM); Middle Sackville (45°55.4’N, 64°21.4’W), sweep at old railway line, 19.vii.2002, J. Forrest & T. Wheeler (2M, 1F, LEM); Murray Beach Prov. Park (46°10.7’N, 63°58.8’W), sweep path in small forest patch, 18.vii.2002, T. A. Wheeler (4M, LEM); Sackville, near Mt. Allison Univ. (45°53.9’N, 64°22.5’W), sweep old garden in vacant lot, 19.vii.2002, J. Forrest & T. Wheeler (3M, LEM). Nova Scotia: Cape Breton Island, North Shore (46°24.8’N, 60°28.5’W), sweep forest path near ocean beach, 21.vii.2002, J. Forrest & T. Wheeler, (6M, LEM); Hampton (44°54.7’N, 68°20.5’W), sweep old meadow above marine beach, 26.vii.2002, J. Forrest & T. Wheeler (10M, LEM). Ontario: Baptiste Lake (45°10’N, 78°00’W), sweep old railway line, clearings in forest, 15.vii.2001, J. Forrest (2M, 1F, LEM); Lanark Co., Mississippi Lake Natl. Wildlife area, sweep lakeshore and marshland 28.vi.2001, M. Pollet (1M, LEM); Ottawa, 30.vi.1990, swept from Poa nemoralis in Acer wood, J.R. Vockeroth (15M, 13F, CNC). Québec: Gaspé, Forillon N.P. Cap des Rosiers (48°50’N, 64°12’W), sweep grass, 06.viii.2000, H. Varady­Szabo (2F, LEM); Gaspé, Haldimand (48°47’N, 64°22’W), sweep path in forest, 18.viii.2001, H. Varady­Szabo (1M, LEM); Gaspé, Petit­Cap, sweep vegetation along path in forest, 08.viii.2001, H. Varady­Szabo (1M, LEM); Gaspé, ZEC York­ Baillargeon (48°49’N, 64°52’W), forest edge near Lac Pauline, 26.vii.2000, H. Varady­ Szabo (1M, 1F, LEM); Gaspésie, l’Anse­au­Griffon nr. Parc Forrillon (48°55’N, 64°19’W), sweep, 31.vii.2001, S. Boucher (1M, LEM); Gaspésie, Ile Bonaventure (48°30’N, 64°10’W), 3km from Côte de Percé, sweep grass, 28.vii.2000, H. Varady­Szabo (1M, LEM); Hudson, Parc Lévy Macdonald (45°27’N, 74°09’W), sweep along path in disturbed forest, 26.vi.2001, J. Forrest (1F, LEM); Terrasse­Vaudreuil, Molson Nature Reserve (45°23.57’N, 73°58.81’W), sweep path in forest, 01.vii.1999, V. Crecco (1F, LEM). UNITED STATES: Maine: Penobscot Co. Grindstone Falls (45°43.8’N, 68°35.4’W), sweep along Penobscot R., 21.vii.2002, J. Forrest & T. Wheeler (2M, LEM). New Hampshire: Coos Co., 1km E Stark (44°36’N, 71°24’W), sweep along Ammonoosuc River, 08.viii.2000, J. Forrest (1M, LEM); Coos Co., White Mt. Nat. For., Dolly Copp (44°19’N, 71°13’W), sweep forest nr. river, 08.viii.2000, T.A. Wheeler (1M, LEM). New York: Hamilton Co., Raquette Lake (43°48.4’N, 74°36.6’W), sweep veg. at lake margin, 31.vii.2002, J. Forrest & T. Wheeler (1M, LEM). JAMAICA: Blue Mtn. Whitfield Hall 4200 ft, 10.ix.1988. sweep at roadside, T.A. Wheeler (1M, LEM).