Pachybrachis luctuosus Suffrian, 1858

Barney, Robert J., LeSage, Laurent & Savard, Karine, 2013, Pachybrachis (Coleoptera, Chrysomelidae, Cryptocephalinae) of Eastern Canada, ZooKeys 332, pp. 95-175 : 117-118

Pachybrachis luctuosus Suffrian, 1858 Habitus 6 ; Map 6 ; Figures 7a , 10a

Pachybrachys luctuosus Suffrian, 1858: 401.

Recognition.

Color black or piceous; ocular lines absent; pronotum and sides of elytra with few yellow marks; elytral punctures confused in scutellar area, in fairly regular rows in apical half; elytral striae deep and quite regular ( Habitus 6 ); aedeagus with terminal nodule and denticle forming small, 90o diamond shape ( Figure 10a ); male size small: length 1.87 ± 0.10 mm, width 0.95 ± 0.11 mm.

Distribution.

A relatively rare Atlantic species distributed from Alabama to New York in the United States ( Riley et al. 2003; Barney, unpublished data). The Parry Sound specimens in Ontario and those of the Île-du-Grand-Calumet in the Ottawa River are two small populations disjunct from the main Atlantic one ( Map 6 ).

Material examined.

ONTARIO: Hastings Co., 20.VI.1952, J. F. Brimley [1♂, CNC]; Parry Sound Dist., Hwy. 69, 12 km S Shawanaga, 13.VII.1995, B. F. & J. L. Carr [1♂, CNC]. Leeds Co., 7.VIII.1950, ex. pine, J. F. Brimley [3♂ 12♀, CNC].

QUÉBEC: Pontiac Co., L’Île-du-Grand-Calumet, 3.VIII.1985, on Pinus resinosa Ait., Larochelle & Larivière [1♂ 1♀, CNC]; Luskville, 4.VII.1985, on Quercus rubra L., Larochelle & Larivière [1♂, CNC].

Host plants.

A large series was taken on pine in Leeds Co., ON. Pachybrachis luctuosus was first reported from Pinus virgiana P. Mill. in Alabama ( Balsbaugh and Hays 1972). This record was extended to the northeastern states by Wilcox (1979), and assumed to be valid as well in West Virginia ( Clark 2000). Specimens from Larochelle & Larivière had label notations reporting collections from Pinus resinosa Ait. and Quercus rubra L.

Comments.

Pachybrachis luctuosus is another of Fall’s (1915) Group C species that have "great variation in the degree of (elytral) maculation." Fall commented that he would not be surprised if Pachybrachis carolinensis Fallwas a paler form of Pachybrachis luctuosus . Our comparison of aedeagi of specimens identified by Fall as either Pachybrachis luctuosus or Pachybrachis carolinensis revealed the same, distinctive form - the subplanar surface with one median subapical denticle. Pachybrachis carolinensis appears to be a larger, more yellow variation, but more work needs to be done. Pachybrachis luctuosus is reported for the first time in Canada, and therefore, is also a first record for ON and QC.

Figures

Habitus 6. Dorsal habitus of Pachybrachis luctuosus. Scale bar, 1 mm.

Map 6. The known distribution of Pachybrachis luctuosus in eastern Canada. IR - Ile-du-Grand-Calumet in Ottawa River.

Figure 7. Elytral punctures and coloration: a in rows in deep striae, Pachybrachis luctuosus b confused in basal half, in rows in apical half, Pachybrachis calcaratus c all confused, Pachybrachis hepaticus d confused and mottled, Pachybrachis spumarius e vittate with marginal vitta interrupted, Pachybrachis bivattatus f black, margined with yellow, Pachybrachis nigriconis carbonarius g entirely black, Pachybrachis luridus.

Figure 10. Aedeagus: a lateral view, Pachybrachis luctuosus b lateral view, Pachybrachis spumarius c apex, dorsal view, Pachybrachis spumarius.