Lasioglossum (Sphecodogastra) seillean Gibbs and Packer, 2013

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 : 92-95

Lasioglossum (Sphecodogastra) seillean Gibbs and Packer , new species

( Figs. 5P , 43G , 44G , 45G , 46G , 68 , 69 , 79F , 81D , 87D )

Holotype. Male. CANADA, Newfoundland , Division 1: Colliers, blueberry farm of Martin Walsh, 26 July 2006 (M. Baird) [ PCYU]; DNA Barcode voucher 06-NF-1012.

Diagnosis. Female L. seillean can be recognised by the combination of head long (L/W ratio = 1.02–1.04) ( Fig. 43G ); mesepisternum finely rugulose (as in Fig. 76D ); inner metatibial spur pectinate, basal teeth longer than width of rachis ( Fig. 5P ); propodeum with lateral carina distinct, extending to dorsal margin, oblique carina strong ( Fig. 79F ); T1 dull due to microsculpture; and T2–T3 without dense apical fimbriae ( Fig. 81D ). In the east, L. seillean is most similar to L. boreale , L. comagenense , and L. quebecense . Lasioglossum boreale and L. comagenense have short teeth on the inner metatibial spur, not exceeding the width of the rachis ( Figs. 5M, 5N ) and T1 polished due to lack of microsculpture ( Figs. 81A, 81B ). Lasioglossum comagenense has a noticeably shorter head (L/W ratio = 0.93–0.96) ( Fig. 43C ). The female of L. boreale has fine propodeal carinae ( Fig. 79C ). Lasioglossum seillean is nearly indistinguishable from L. quebecense but averages smaller in size (5.8–6.5 mm vs. 6.5–7.0 mm).

Male L. seillean can be recognised by the combination of clypeus with yellow on distal half ( Fig. 44G ); 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 (as in Fig. 85A ); S2–S3 with sparse punctures (as in Fig. 88A ); metatibial base brown or with small yellow spot; and basitarsi bright yellow ( Fig. 69 ). Males of L. boreale and L. comagenense have a large yellow patch on the metatibial base ( Figs. 54 , 57 ). The clypeal maculation is smaller on L. seillean ( Fig. 44G ) than on L. boreale , L. comagenense and L. quebecense ( Figs. 44B, 44C, 44F ). The unique shape of the retrorse lobe ( Figs. 87D, 87F ), which is long, gently curved, parallel-sided to a rounded apex, is the most reliable character for distinguishing L. seillean males from L. boreale , L. comagenense , and L. quebecense ( Figs. 87A, 87B, 87C, 87E ).

Description. FEMALE. Length 5.8–6.5 mm. Head length 1.67–1.91 mm. Head width 1.61–1.88 mm. Wing length 4.6–5.4 mm. (n=3)

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 orange-brown. Metasomal terga black-brown.

Structure. Head long (L/W ratio = 1.02–1.04). Clypeus 1/2 - 2/3 below suborbital line. Eyes convergent below (UOD:LOD = 1.09–1.16). 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 six, basal teeth slightly longer than width of rachis. Propodeal lateral carina reaching dorsal margin, oblique carina high, separating dorsolateral slope from posterior surface.

Surface sculpture. Supraclypeal area polished medially, punctures sparse (i=1–2.5d). Gena lineolate, postgena smoother. Mesoscutum weakly imbricate to polished; punctures dense (i≤d), except posteromedially (i=1–1.5d). Mesepisternum finely rugulose, smoother ventrally. Metapostnotum carinate-rugose. Propodeum imbricatetessellate. Metasomal terga mostly 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 dense, medially-interrupted apical fimbriae. T1 with sparse, erect plumose hairs. T2–T4 basally with sparse, tomentum. Metasomal sterna with plumose scopa.

MALE. Length 5.9–7.0 mm. Head length 1.62–1.88 mm. Head width 1.55–1.80 mm. Wing length 4.2–4.9 mm. (n=3)

Colour. Head and mesosoma black. Clypeus yellow apically. Mandible brown. Labrum yellow basally. Antenna black, except ventral surface of flagellum orange, less so on F10–F11. Legs dark brown, except tarsi and apex of protibia yellow, anterior surface of protibia infused with testaceous, metatibia rarely with small yellow spot. Wing membrane hyaline. Pterostigma orange-brown. Metasomal terga dark brown, apical margins pale brown.

Structure. Head long (L/W ratio = 1.04–1.06). Clypeus 2/3–3/4 below suborbital tangent. Mandible short, reaching opposing clypeal angle. Flagellomeres, except F1, elongate, F2 longer than F1 and pedicel combined. Eyes strongly convergent below (UOD:LOD = 1.2 8–1.46). Gena clearly narrower than eye. Pronotum smoothly rounded. Propodeal lateral carina reaching dorsolateral slope.

Surface sculpture. Supraclypeal area imbricate, with sparse, shallow punctures (i=1–1.5d). Gena and postgena lineolate. Mesoscutum weakly polished, reticulate anteriorly; punctures dense (i≤d) but clearly separated posteromedially (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. Metasomal sterna sparsely, obscurely punctate (i=2–5d).

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. 45G , 46G , 87D, 87F . Gonostylus moderately-sized, with short setae. Retrorse lobe long, gently curved but not reflexed, with apex rounded ( Fig. 87F ).

Biology. One of us (LP) excavated two nests of this species at the blueberry barrens in Sydney, Nova Scotia. The brood cells were gathered in a cluster, but the entire nest was in sandy soil with densely matted roots making detailed architectural study impossible. Both nests appear to have been solitary. The range of L. seillean is apparently limited to high latitudes with short flight seasons that would preclude the formation of annual eusocial colonies.

A chromosome count was obtained from a larva using the methods of Imai et al. (1977) and provided an n of 4, though given the possibility of cleptoparasitism by an unidentified species of Sphecodes that was common in the area, it cannot be stated with certainty that the count obtained was not of the parasite. This is the smallest chromosome number yet reported for halictid bees ( Packer & Owen 1989).

DNA barcodes. Ten individuals were sequenced (maximum intraspecific p-distance: 1.2%). The minimum interspecific p-distance separating L. seillean from L. comagenense and L. quebecense is 6.0% and 5.8%, respectively. Lasioglossum seillean differs from the other fulvicorne-fratellum species included here by 24 fixed substitutions: 48(T), 78(C), 141(C), 156(T), 180(T), 183(T), 204(A), 291(T), 309(A), 322(A), 333(C), 336(C), 351(A), 354(C), 375(C), 399(T), 417(C), 498(C), 538(C), 594(C), 600(C), 609(T), 633(T), and 651(T) (see Table 2).

Range. Fig. 70 .

Paratypes. 177 (59 females, 119 males). Deposited in ACNS, CNC, CUIC, PCYU, and ROMent .

CANADA. ALBERTA: Bow R. [3 ♂♂] ; NEW BRUNSWICK: Charlotte Co.: St. Andrews; Gloucester Co. : Haut-Shippagan [1 ♀ ACNS]; Haut Tilley Rd. [3 ♀♀ ACNS]; Northumberland Co. : Neguac [1 ♀ 1 ♂ ACNS] ; NEWFOUNDLAND: Terra Nova N.P. [27 ♀♀ 7 ♂♂ PCYU]; Division 4: Harmon Field [16 ♀♀ CNC]; Division 10: Goose Bay ; [13 ♂♂ CNC] ; NORTHWEST TERRITORIES: Fort Simpson [1 ♂ CNC]; Hwy 3, nr. Rae [1 ♀ PCYU] ; NOVA SCOTIA: Sydney Barrens [1 ♀ 1 ♂ PCYU]; Inverness Co.: French Mt. , Highlands N.P. [2 ♀♀ CUIC] ; ONTARIO: Cochrane Dist.: Hearst [1 ♂ PCYU, 7 ♂♂ ROMent]; Iroquois Falls; [5 ♂♂ ROMent]; Porquis [1 ♂ ROMent]; Kenora Dist. : Red Lake [1 ♀ 1 ♂ ROMent]; Rainy River Dist. : Quetico Park [1 ♀ ROMent]; Thunder Bay Dist. : Linko [1 ♂ CUIC, 1♀ 2 ♂♂ ROMent]; Upsala [1 ♂ CUIC, 11 ♂♂ ROMent]; Timiskaming Dist. : Kirkland Lk. [1 ♀ ROMent] ; PRINCE EDWARD ISLAND: Kings Co.: Albion Cross [5 ♀♀ 2 ♂♂ ACNS]; Queens Co. : Dromore [1 ♂ ACNS]; Glenroy [1 ♀ 1 ♂ ACNS]; St. Andrews [2 ♀♀ 3 ♂♂ ACNS] ; QUEBEC: Côte-Nord Reg.: Forestville [2 ♀♀ 55 ♂♂ CNC]; Gaspésie-Îles-de-la-Madeleine Reg.: Ste. Anne des Monts ; [1 ♀ CNC] .

USA. MICHIGAN: Alger Co.: Grand Marais [4♀♀ CUIC] .

Floral records. Lasioglossum seillean is a frequent visitor of Vaccinium (Ericaceae) . Large numbers of females have been collected in blueberry fields. It has also been collected on Taraxacum (Asteraceae) and Melilotus albus Medik (Fabaceae) .

Etymology. The specific epithet is a noun in apposition and is taken from the Scots Gaelic word “seillean”, which means “ bee ”.

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 54. Lateral habitus of male Lasioglossum (Sphecodogastra) boreale (Svensson, Ebmer & Sakagami). Scale bar = 1 mm.

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

FIGURE 68. Lateral habitus of female Lasioglossum (Sphecodogastra) seillean Gibbs & Packer. Scale bar = 1 mm.

FIGURE 69. Lateral habitus of male Lasioglossum (Sphecodogastra) seillean Gibbs & Packer. Scale bar = 1 mm.

FIGURE 70. Distribution map of Lasioglossum (Sphecodogastra) seillean Gibbs & Packer. 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 85. Metasomal sterna of male Lasioglossum (Spheocodagastra) with arrows indicating pubescence and S6 medial area. (A) L. boreale showing short, sparse hairs and normal S6. (B) L. oenotherae showing long, dense hairs and concave S6.

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.