Pachybrachis pectoralis (F. E. Melsheimer, 1847)

Barney, Robert J., LeSage, Laurent & Savard, Karine, 2013, Pachybrachis (Coleoptera, Chrysomelidae, Cryptocephalinae) of Eastern Canada, ZooKeys 332, pp. 95-175 : 128-129

publication ID

https://dx.doi.org/10.3897/zookeys.332.4753

persistent identifier

https://treatment.plazi.org/id/FB1527B9-8B9E-557F-9728-0AD65C7C294C

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ZooKeys by Pensoft

scientific name

Pachybrachis pectoralis (F. E. Melsheimer, 1847)
status

 

Pachybrachis pectoralis (F. E. Melsheimer, 1847) Habitus 13 View Habitus 13 ; Map 13 View Map 13 ; Figure 1a View Figure 1

Cryptocephalus pectoralis F. E. Melsheimer, 1847: 171.

Pachybrachis sobrinus Haldeman, 1849: 262.

Pachybrachis oculatus Suffrian, 1852: 178.

Pachybrachis sticticus Blatchley, 1910: 1130.

Recognition.

Form, especially of the male, narrower than usual; color dull yellow, maculate with brown or black ( Habitus 13 View Habitus 13 ); surface not or scarcely shining; eyes narrowly separated; ocular lines present ( Figure 1a View Figure 1 ); front tibiae sinuate on inner margin beyond middle; front claws of male obviously, though not greatly, enlarged; male size small: length 1.92 ± 0.07 mm, width 0.96 ± 0.04 mm.

Distribution.

Eastern species distributed from Nebraska to Texas to Atlantic Coast in the United States ( Riley et al. 2003). In eastern Canada, Pachybrachis pectoralis has been found in southern Ontario and the Ottawa Valley in Québec ( Map 13 View Map 13 ).

Material examined.

ONTARIO: Hastings Co., 10.vii.1938, J. F. Brimley [2♀, CNC]; same data, except 5.VIII.1957 [1♀, CNC]; Muskoka Dist., Norway Point Lake of Bays, 30.XI.1922, J. McDunnough [1♀, CNC]; Prince Edward Co., 3.VIII.1938, J. F. Brimley [3♂ 3♀, CNC]; Kawartha Gull Lake, 2.VIII.1943, J. F. Brimley [2♂, CNC]; same data, except 19.VII.1950 [1♀, CNC]; Toronto Co., Toronto, 15-30.VI.1927, L. J. Milne [1♀, CNC]; Unknown Co., East Ontario [1♂, CNC].

QUÉBEC: Gatineau Co., Mont King, Parc de la Gatineau, 19.VIII.1996, L. LeSage [8♂ 13♀, CNC]; same data, except 6.IX.1996 [1♀, CNC]; same data, except 28.V.1997 [1♀, CNC]; same data, except 21.VII.1997 [1♂ 3♀, CNC]; Pontiac Co., Luskville, 4.VII.1985, ex. Quercus rubra L. Larochelle & Larivière [1♀, CNC]; same data except 30.VII.1985, ex. Quercus alba L. [1♂, CNC]; Vaudreuil Co., Rigaud, A. Robert [2♂ 2♀, CEUM]; same data, except 20.VIII.1984, ex. Quercus rubra L., Larochelle & Larivière [2♂, CNC]; same data except 19.VIII.1985, ex. Quercus rubra L., Larochelle & Larivière [1♀, CNC].

Host plants.

No information is available from the specimens examined. According to Blatchley (1924a, b), Fall (1915), Barney (1984) and Clark (2000), Pachybrachis pectoralis is associated with common locust ( Robinia pseudoacacia L.) ( Fabaceae ). Larochelle’s specimens were found on Quercus alba L. and Quercus rubra L. Additional potential hosts are given in Clark et al. (2004).

Comments.

No specimens from New Brunswick and Nova Scotia, from where this species was reported by LeSage (1991) and Riley et al. (2003), were located, although the material of all the important collections of eastern Canada was examined. The Ottawa River Valley is the northernmost limit of Pachybrachis pectoralis , in Québec. This species may extend further north to the Maritime Provinces along the Atlantic Coast, but it has not yet been recorded from Maine ( Riley et al. 2003; Majka et al. 2011).