Lasioglossum (Sphecodogastra) comagenense ( Knerer & Atwood 1964 )

Gibbs, Jason, Packer, Laurence, Dumesh, Sheila & Danforth, Bryan N., 2013, Revision and reclassification of <i> Lasioglossum </ i> (<i> Evylaeus </ i>), <i> L. </ i> (<i> Hemihalictus </ i>) and <i> L. </ i> (<i> Sphecodogastra </ i>) in eastern North America (Hymenoptera: Apoidea: Halictidae), Zootaxa 3672 (1), pp. 1-116 : 80-83

Lasioglossum (Sphecodogastra) comagenense ( Knerer & Atwood 1964)

( Figs. 5N , 43C , 44C , 45C , 46C , 56 , 57 , 76D , 79D , 81B , 87B , 88A )

Evylaeus comagenensis Knerer and Atwood 1964, p. 959 (♂)

Holotype. ♀ Canada, Ontario, Thunder Bay Dist., Upsala 14.viii.1962 on Solidago [ROMent]. Examined.

Fixed by original designation. (Labels read: “ Upsala Ont. 14.VIII.1962 G. Knerer [partially handwritten]/ Solidago / Evylaeus comagenensis Knerer & Atwood Holotype [handwritten on red label]/ Holotype Lasioglossum comagenense (Knerer & Atwood) ROMent Spec. No. 83643 ROMent000629002”).

Lasioglossum (Evylaeus) comagenense (in Krombein 1967: catalogue)

Diagnosis. Female L. comagenense can be recognised by the combination of head short (L/W ratio = 0.93–0.96) ( Fig. 43C ); mesepisternum finely rugulose ( Fig. 76D ); inner metatibial spur pectinate-denticulate, teeth shorter than width of rachis ( Fig. 5N ); propodeum with lateral carina distinct, extending to dorsal margin, oblique carina strong ( Fig. 79D ). In the east, L. comagenense is most similar to L. boreale , L. quebecense , and L. seillean . Lasioglossum quebecense and L. seillean both have longer heads (L/W ratio = 1.00–1.04) ( Figs. 43F, 43G ) and long teeth on the inner metatibial spur, distinctly exceeding the width of the rachis ( Figs. 5O, 5P ). The female of L. boreale has a longer head (L/W ratio = 0.98–1.00) ( Fig. 43B ) and fine propodeal carinae ( Fig. 79C ).

Male L. comagenense can be recognised by the combination of clypeus with yellow on distal half ( Fig. 44C ); mandible short, not extending much beyond opposing clypeal angle; F2 long subequal to scape; propodeal lateral carina strong; metasomal sterna nearly bare, hairs present but very short; S2–S3 with sparse punctures ( Fig. 88A ); and basitarsi bright yellow ( Fig. 57 ). The unique shape of the retrorse lobe ( Fig. 87B ), which is distinctively recurved apically, is the most reliable character for distinguishing L. comagenense males from L. boreale , L. quebecense , and L. seillean ( Figs. 87A, 87C, 87D ).

Redescription. FEMALE. Length 6.1–7.2 mm. Head length 1.76–2.00 mm. Head width 1.84–2.10 mm. Wing length 5.1–5.7 mm. (n=6)

Colour. Head and mesosoma black. Antenna black, except ventral surface of flagellum reddish brown-orange. Tegula dark reddish brown. Legs dark brown, except medio- and distitarsi reddish brown. Wing membrane hyaline, faintly dusky. Pterostigma testaceous. Metasomal terga black-brown, apical margins pale brown.

Structure. Head wide (L/W ratio = 0.93–0.96). Clypeus ¾ below suborbital line. Eyes convergent below (UOD:LOD = 1.06–1.11). Gena subequal to eye width. Ocelli normal. Pronotum smoothly rounded. Protibial spur with apical serrations as long as width of malus. Inner metatibial spur pectinate, teeth 4–6, basal teeth equal to width of rachis. Propodeal lateral carina reaching dorsal margin, oblique carina high, separating dorsolateral slope from posterior surface.

Surface sculpture. Supraclypeal area weakly polished medially, punctures sparse (i=1–2d). Gena lineolate, postgena smoother. Mesoscutum imbricate, dull; punctures dense (i≤d), except medially (i=1–1.5d). Mesepisternum finely rugulose, smoother ventrally. Metapostnotum carinate-rugose. Propodeum imbricatetessellate. Metasomal terga weakly coriarious, T1 polished; punctures dense, sparser posteromedially, T2 apical impressed area impunctate medially.

Pubescence. Head and mesosoma with sparse plumose hairs. Metafemoral scopa with dense plumose hairs. Metasomal terga with relatively sparse, medially-interrupted apical fimbriae. T1 with sparse, erect plumose hairs. T2–T4 basally with sparse, tomentum. Metasomal sterna with plumose scopa.

MALE. Length 6.4–7.8 mm. Head length 1.82–2.05 mm. Head width 1.77–1.96 mm. Wing length 4.8–5.4 mm. (n=6)

Colour. Head and mesosoma black. Clypeus yellow apical half. Mandible brown. Labrum yellow. Antenna black, except ventral surface of flagellum orange, less so on F10–F11. Legs dark brown, except tarsi, bases and apices of tibiae yellow, anterior surface of protibia yellow-testaceous, sometimes anterior surface of mesotibia and ventral surface of metatibia yellow-testaceous. Wing membrane hyaline. Pterostigma orange. Metasomal terga dark brown, pale brown apically.

Structure. Head long (L/W ratio = 1.01–1.04). Mandible short, reaching opposing clypeal angle. Flagellomeres, except F1 elongate, F2 longer than F1 and pedicel combined, subequal to scape. Eyes strongly convergent below (UOD:LOD = 1.27–1.39). Gena narrower than eye. Pronotum smoothly rounded. Propodeal lateral carina reaching dorsolateral slope, contiguous with strong oblique carina.

Surface sculpture. Supraclypeal area imbricate, with relatively dense punctures (≤d). Gena lineolate. Mesoscutum imbricate, reticulate anterolaterally; punctures dense but clearly separated medially (i=1–1.5d). Mesepisternum rugulose, weakly so ventrally. Metapostnotum anastomosingly rugose. Propodeum rugulose, posterior surface rugose. Metasomal terga polished; punctures deep, close basally. T2–T6 apical impressed areas impunctate.

Pubescence. Head and mesosoma with sparse plumose hairs. Face below antennal sockets with dense tomentum, lower paraocular area obscured, supraclypeal area and clypeus partially obscured, clypeus bare on distal half. Propodeum largely bare, with scattered plumose hairs. Metasomal terga nearly bare, without apical fimbriae. T2 with narrow, basolateral patch of tomentum. Metasomal sterna nearly bare, with sparse, short, plumose hairs (<1 OD).

Terminalia . As shown in Figs. 45C , 46C , 87B . Gonostylus small, truncate, with short setae. Retrorse lobe long, recurved apically.

Taxonomic notes. Lasioglossum comagenense belongs to the fulvicorne-fratellum species-group ( Ebmer 1974; Svensson et al. 1977). There is a close resemblance with L. nigrum ( Viereck 1903) , which was originally described from material collected at high elevations in New Mexico. The retrorse lobe of L. nigrum is also recurved apically. The same may be true of L. peraltum ( Cockerell 1901a) , another high-elevation species from New Mexico, based on non-type material identified as such. Unfortunately, the type specimen of L. peraltum is missing the metasoma (JG, pers. obs.). Lasioglossum nigrum and L. peraltum differ in the colour of the labrum, mandible, antenna, and wing. DNA barcodes do not distinguish specimens identified as L. nigrum and L. comagenense (see below). Males of these two western species seem to have longer heads (L/W ratio ≈ 1.10) and denser basal pubescence on the metasomal terga. For this reason, we do not believe L. comagenense to be synonymous with either L. nigrum or L. peraltum . Additional study is needed to determine if L. nigrum is a junior synonym of L. peraltum .

Biology. Lasioglossum comagenense exhibits solitary, semisocial, and delayed eusocial behaviour ( Batra 1990; Packer 1989a, 1989b, 1993; see Schwarz et al. 2007 for review of terminology). Colonies are often pleiometrotic with foundresses digging upwards from hibernacula ( Packer 1993). The species is restricted to northern latitudes with the exception of high elevation populations extending south to Pennsylvania. The short flight season at these latitudes and altitudes excludes the possibility of annual eusocial colonies forming. Nest entrances are usually at the edges of stones and small rocks and the brood cells are made in a cluster surrounded by a cavity, sometimes directly beneath a stone ( Packer et al. 1989b).

DNA barcodes. Five specimens ranging from Ontario to British Columbia were sequenced (maximum intraspecific p-distance: 0%). The minimum p-distance separating L. comagenense and L. boreale is 1.2%. Lasioglossum comagenense differs from the other fulvicorne-fratellum species included here by three fixed substitutions: 132(C), 180(A), and 645(C) (see Table 2). Comparison of DNA barcodes from L. comagenense and L. nigrum revealed no fixed differences, supporting the close relationship or even synonymy of these two nominal species.

Range. Fig. 58 .

Material examined. 262 (169 females, 93 males). Deposited in ACNS, CNC, CUIC, MSUC, PCYU, and ROMent .

CANADA. BRITISH COLUMBIA: Capital Reg.: Royal Oak; Victoria ; East Kootenay Reg.: Cranbrook; NEW BRUNSWICK: Charlotte Co.; NOVA SCOTIA: Colchester Co.: Truro; Richmond Co.: Cape Breton, Iris Cove Rd.; Cape Breton, River Denys Mtn. Rd.; ONTARIO: Arctic Watershed; Algoma Dist. : Garden River; Kabinakagami R.; Missinaibi R.; Cochrane Dist.: Hearst; Iroquois Falls; Porquis; Haliburton Co.: Algonquin P.P.; Algonquin P.P., by Crossbar Lk.; Algonquin P.P., by Madawaska Lk.; Haliburton, Small Kennisis; Kennisis Lake; Muskoka Dist.: Dorset; Parry Sound Dist.: Parry Sound; Rainy River Dist.: Quetico P.P.; Sudbury Dist.: Peach Lk.; Thunder Bay Dist.: Black Sturgeon Lk.; Linko; Raleigh; Rossport; Schreiber; Upsala; Timiskaming Dist.: Elk Lake; Kenabeek; Kirkland Lk., airport site; PRINCE EDWARD ISLAND: Kings Co.: St. Patrick Rd.; West St. Peters; Prince Co.: Grand River; Queens Co.: Dromore; Glenroy; Mt. Vernon; Scotchfort; St. Andrews; York; QUEBEC: Côte-Nord Reg.: Forestville; Jamésie Reg.: Mistassini; Kamouraska Co.: Parke Reserve; La Jacques-Cartier Reg.: Duchesnay; Mauricie Reg.: Lac Mondor, Ste. Flore; Témiscamingue Reg.: Laniel; YUKON TERRITORY: Alcan Hwy., mile 1068.

USA. MAINE: Aroostook Co.: Oxbow; Piscataquis Co .; MICHIGAN: Antrim Co.; Dickinson Co.: Sagola; Waucedah; Gogebic Co. : Watersmeet; Keweenaw Co. ; Marquette Co .; MINNESOTA: Clearwater Co.: Bagley ; NEW HAMPSHIRE: Coos Co.: Glen House; Mt. Washington; Randolph ; NEW YORK: Essex Co.: Heart Lake ; WASHINGTON: Pierce Co.: Mt. Rainier, Dege Peak; Thurston Co. : Rainier, 2 mi NW .

Figures

FIGURE 5. Drawings of inner metatibial spurs of female Lasioglossum subgenera Hemihalictus (A-K), Evylaeus (L), and Sphecodogastra (M-Q). (A) L. birkmanni. (B) L. fedorense. (C) L. foxii. (D) L. inconditum. (E) L. lustrans. (F) L. macoupinense. (G) L. nelumbonis. (H) L. pectinatum. (I) L. pectorale. (J) L. sopinci. (K) L. swenki. (L) L. cinctipes. (M) L. boreale. (N) L. comagenense. (O) L. quebecense. (P) L. seillean. (Q) L. truncatum. See McGinley (2003) figures 61, 62, and 65 for images of inner metatibial spurs of L. lusorium, L. oenotherae, and L. texanum.

FIGURE 43. Faces of female Lasioglossum subgenera Evylaeus (A) and Sphecodogastra (B-I) in frontal view. (A) L. cinctipes. (B) L. boreale. (C) L. comagenense. (D) L. lusorium. (E) L. oenotherae. (F) L. quebecense. (G) L. seillean. (H) L. texanum (I) L. truncatum. Scale bar = 1 mm.

FIGURE 44. Faces of male Lasioglossum subgenus Evylaeus (A) and Sphecodogastra (B-I) in frontal view. (A) L. cinctipes. (B) L. boreale. (C) L. comagenense. (D) L. lusorium. (E) L. oenotherae. (F) L. quebecense. (G) L. seillean. (H) L. texanum (I) L. truncatum. Scale bar = 1 mm.

FIGURE 45. Genital capsules of male Lasioglossum subgenera Evylaeus (A) and Sphecodogastra (B-I) in dorsal view. (A) L. cinctipes. (B) L. boreale. (C) L. comagenense. (D) L. lusorium. (E) L. oenotherae. (F) L. quebecense. (G) L. seillean. (H) L. texanum (I) L. truncatum. Scale bar = 1 mm.

FIGURE 46. Genital capsules of male Lasioglossum subgenus Evylaeus (A) and Sphecodogastra (B-I) in ventral view. (A) L. cinctipes. (B) L. boreale. (C) L. comagenense. (D) L. lusorium. (E) L. oenotherae. (F) L. quebecense. (G) L. seillean. (H) L. texanum (I) L. truncatum. Scale bar = 1 mm.

FIGURE 56. Lateral habitus of female Lasioglossum (Sphecodogastra) comagenense (Knerer & Atwood). Scale bar = 1 mm.

FIGURE 57. Lateral habitus of male Lasioglossum (Sphecodogastra) comagenense (Knerer & Atwood). Scale bar = 1 mm.

FIGURE 58. Distribution map of Lasioglossum (Sphecodogastra) comagenense (Knerer & Atwood). Heat map indicates predicted suitable range based on maximum entropy niche-modelling. Black circles indicate actual geo-referenced specimen records.

FIGURE 76. Mesepisternum of female Lasioglossum. (A) L. inconditum showing weak, rugulose sculpture. (B) L. pectinatum showing punctation. (C) L. pectorale showing coarse, rugose sculpture throughout. (D) L. comagenense showing weak, rugulose sculpture. (E) L. lusorium showing appressed pubescense. (F) L. truncatum showing rugose sculpture becoming rugulose anterior to mesocoxa.

FIGURE 79. Propodeum and metapostnotum of female Lasioglossum (Evylaeus) and L. (Sphecodogastra). (A) L. cinctipes showing coarse, rugose sculpture. (B) L. truncatum showing coarse, rugose sculpture. (C) L. boreale showing fine sculpture and weak propodeal carinae. (D) L. comagenense showing fine sculpture and distinct propodeal carinae. (E) L. quebecense showing fine sculpture and distinct propodeal carinae. (F) L. seillean showing fine sculpture and distinct propodeal carinae.

FIGURE 81. Metasomal terga of female Lasioglossum (Sphecodogastra) in the fulvicorne-fratellum species-group. (A) L. boreale. (B) L. comagenense. (C) L. quebecense showing distinct apicolateral fimbriae. (D) L. seillean.

FIGURE 87. Lateral view of gonostylus and retrorse lobe of Lasioglossum (Sphecodogastra) in the fulvicorne-fratellum species-group. (A) L. boreale. (B) L. comagenense. (C) L. quebecense. (D) L. seillean. Ventral view of retrorse lobe. (E) L. quebecense. (F) L. seillean. Arrows indicate apex of retrorse lobe.

FIGURE 88. False colour image of metasomal sterna of Lasioglossum (Sphecodogastra) in the fulvicorne-fratellum speciesgroup. (A) L. comagenense showing few distinct punctures. (B) L. boreale showing many distinct punctures.