Pachybrachis obsoletus Suffrian, 1852

Barney, Robert J., LeSage, Laurent & Savard, Karine, 2013, Pachybrachis (Coleoptera, Chrysomelidae, Cryptocephalinae) of Eastern Canada, ZooKeys 332, pp. 95-175 : 122-124

Pachybrachis obsoletus Suffrian, 1852 Habitus 10 ; Map 10

Pachybrachys obsoletus Suffrian, 1852: 200.

Recognition.

Background color yellow, with numerous, usually not sharply outlined black spots on both pronotum and elytra ( Habitus 10 ); eyes distant; ocular lines faint; male size small: length 1.87 ± 0.16 mm, width 0.98 ± 0.08 mm.

Distribution.

Species broadly distributed from North Dakota to New Mexico to Atlantic Coast in the United States ( Riley et al. 2003), and in Canada from British Columbia to New Brunswick. In eastern Canada, it is found in Ontario, Québec and New Brunswick ( Map 10 ).

Material examined.

NEW BRUNSWICK: Kent Co., Kouchibouguac National Park, 21.VII.1977, Code 5680L, D. J. Brown [1♀, CNC]; same data, except 17.VII.1978, Code 7291K, D. B. Lyons [1♀, CNC]; Queens Co., Canning Grand Lake near Flowers Cove, 1.VII.2004, D. Sabine and R. Webster [2♂ 2♀, RWIC]; White’s Cove, Grand Lake, 24.VII.1957, ex. Salix lucida [2♂ 2♀, CNC]; Sunbury Co., 9.5 km NE Jct. 101 & 645, 22.VII.2007, R. P. Webster [1♀, RWIC]; York Co., Fredericton, French Lake, 20.VII.1931, C. W. Maxwell [1♀, LEM]; Fredericton, 22.VII.1936, R. E. Balch [1♀, CNC]; French Lake, 2.VI.1928, W. J. Brown [1♀, CNC].

ONTARIO: Carleton Co., Carp, 5.VII.1932, W. J. Brown [1♂, CNC]; Merivale, 16.VII.1936, W. J. Brown [2♀, CNC]; Stittsville, 18.VII.1963, J. F. McAlpine [1♂, CNC]; Stittsville, 18.VIII.1963, Malaise trap [1♀, CNC]; Durham Co., Durham, VI.1969, [1♀, CNC]; Hastings Co., 10.VII.1938, J. F. Brimley [2♀, CNC]; same data, except 16.VII.1950 [2♀, CNC]; same data, except 31.VI.1936 [1♀, CNC]; Marmora, 19.VI.1952, J. R. Vocheroth [1♂, CNC]; same data, except 4.VII.1952, J. R. McGillis [1♀, CNC]; same data, except 18.VIII.1952, E. H. N. Smith [1♀, CNC]; Kent Co., Tilbury, 20.VIII.1947, on willow, S. D. Hicks [1♀, CNC]; Lambton Co., Grand Bend, 11.VII.1939, G.E. Shewell [1♀, CNC]; same data except 20.VII.1939 [1♀, CNC]; Lanark Co., Bell’s Corners, 6.VI.1942, F.I. Survey 1942, Rec 5436C, White Pine [1♀, CNC]; Leeds Co., Mulcaster Island, Saint-Lawrence Island National Park, 17.VIII.1976, Sweeping Pinus strobus , Code 4438, W. Reid [1♀, CNC]; Thwartway Island, Saint-Lawrence Island National Park, 18.VII.1976, Malaise trap, Code 4147-M, W. Reid [3♀, CNC]; Middlesex Co., Coldstream, 22.VI.1922, A. A. Wood [1♂ 5♀, CNC]; Nipissing Co., North Bay, 11.VII.1972, E. J. Kiteley [1♂, CNC]; Peterborough Co., 3.VII.1958, J. F. Brimley [1♀, CNC]; Prescott, Co., Alfred Bog, 7.VI.1982, sweeping vegetation in a bog, L. LeSage [2♂, CNC]; Prince Edward Co., 12.VII.1914, J. F. Brimley [1♀, CNC]; same data, except 29.XI.1914 [1♀, CNC]; same data, except 11.VII.1920 [1♂, CNC]; same data, except 15-30.VII.1922, J. F. Brimley [3♀, CNC]; same data, except 19.VI.1926 [1♀, CNC]; same data, except 6.VII.1935 [1♂, CNC]; same data, except 28.VI.1936 [1♀, CNC]; same data, except 26.VII.1936 [1♀, CNC]; same data, except 17.VIII.1938 [1♀, CNC]; same data, except 9.VII.1941 [1♀, CNC]; same data, except 5.VII.1942 [3♀, CNC]; same data, except 18.VI.1947 [1♀, CNC]; same data, except 29.VIII.1948 [1♀, CNC]; same data, except 29.VI.1949 [1♀, CNC]; same data, except 31.VIII.1949 [1♂, CNC]; same data, except 19.VII.1950 [1♀, CNC]; same data, except VII.1953 [2♂ 4♀, USNM]; same data, except 24.VII.1955 [1♀, CNC]; same data, except 29.VII.1956 [4♂ 10♀, CNC]; same data, except 26.VI.1966 [1♀, CNC]; Renfrew Co., Chalk River, 3.VIII.1937, J. M. Cameron [1♀, LEM]; Russell Co., Mer Bleue, 30.VI.1932, W. J. Brown [1♀, CNC]; same data, except 17.VII.1936 [1♀, CNC]; same data, except 2.VII.1938, G. E. Shewell [1♂, CNC]; Sudbury Co., Sudbury, 4.VIII.1979, R. S. Anderson [1♀, CNC]; Thunder Bay Dist., Black Sturgeon Lake, 1-15.VIII.1956, Lindberg [1♂1♀, CNC]; Jarvis Island, 20.VIII.1952, on white pine, J. F. McAlpine [1♂, CNC]; Manitouwadge, 22.VI.1988, T. Baker [1♂, CNC]; same data, except 30.VII.1992 [1♂, CNC]; Toronto Co., Toronto, 27.V.1896, H. R. [1♀, LEM]; Quetico Provincial Park, 8.VIII.1982, C. B. Barr [2♀, LSAM]; Unknown Co., East Ontario [1♀, CNC].

QUÉBEC: Abitibi Co., Duparquet, 7.VIII.1983, ex. Pinus banksiana Lamb., A. Larochelle [1♀, CNC]; Berthier Co., Berthierville, 8.VII.1950, A. Robert [1♀, CEUM]; Lanoraie, VII.1935, G. Chagnon [1♀, H. C. Fall, CEUM]; Charlevoix-Est Co., Clermont, 17.VIII.1982, ex. Pinus strobus L., A, Larochelle [2♀, CNC]; Port-au-Saumon, 19.VIII.1982, ex. spruce sp., A. Larochelle [1♂, CNC]; Drummond Co., Saint-Cyrille, 10.VII.1982, ex. Cassandra calyculata , L. LeSage [1♂ 1♀, CNC]; Gatineau Co., Wakefield, 5.VIII.1974, ex. Pinus strobus , R. Sexton [1♀, CNC]; Île-Jésus Co., Île-Jésus, 5.VII.1935, G. Chagnon [1♀, CEUM]; Montcalm Co., Parc du Mont-Tremblant, 13.VIII.1932, A. Robert [1♂, CEUM]; Montgomery Co., Saint-Jean-d’Orléans, 22.VII.1957, J. L. Laliberté [1♀, IDM]; Montmagny Co. Montmagny, 8.VIII.1981, ex. Pinus strobus L., A. Larochelle [1♀, CNC]; Pontiac Co., Beech Grove, 15.VIII.1948, S. D. Hicks [3♀, CNC]; Saguenay Co., Grandes-Bergeronnes, 15.VIII.1982, ex. Pinus resinosa Ait., A, Larochelle [1♀, CNC]; Stanstead Co., Barnston, 26.VIII.1984, ex. Thuya sp., Larochelle & Larivière [1♀, CNC]; Terrebonne Co., Terrebonne, 1.VII.1933, J. Ouellet [1♀, CEUM]; Vaudreuil Co., Rigaud, 19.VII.1985, ex. Pinus strobus L., Larochelle & Larivière [2♀, CNC]; same data except 20.V.1977, sweeping sumac sp., E. J. Kiteley [1♀, CNC]; Saint-Lazare, 6.VIII.1985, ex. Betula papyrifera Marsh., A. Larochelle [1♂, CNC].

Host plants.

Pachybrachis obsoletus may be associated with peat bogs in eastern Canada. Specimens were collected in Alfred Bog ( Pope 2011), and Mer Bleue ( NCC 2011b; Wikipedia 2011), two well-known bogs of Ontario. The Lanoraie specimens, in Québec, were collected in an ecological preserve, which includes several fens and bogs ( MDDEP 2011). Larochelle specimens, also from Québec, had a wide range of potential plant associations. Leather leaf ( Cassandra calyculata (L.) D. Don.) ( Ericaceae ) is definitively a host (LeSage, collecting and personal observations), whereas the beetles’ presence on white pine ( Pinus strobus ) ( Pinaceae ) is very likely incidental. Sweeping from willows ( Salix spp.) ( Salicaceae ) was reported by Barney et al. (2011). Additionally, Pachybrachis obsoletus was reported as causing light injury to cultivated roses in Saskatoon, Saskatchewan, but the species identification cannot be confirmed ( Arnason 1942, 1943; Arnason et al. 1946; King et al. 1944, 1945; Campbell et al. 1989).

Comments.

Pachybrachis obsoletus has a broad distribution from Manitoba to Oklahoma and eastwards to the Atlantic Ocean, with Alberta and British Columbia disjunct from this main area ( Riley et al. 2003). It is reported here for the first time from NB.

Figures

Habitus 10. Dorsal habitus of Pachybrachis obsoletus. Scale bar, 1 mm.

Map 10. The known distribution of Pachybrachis obsoletus in eastern Canada. SR - Saguenay River.