Lasioglossum (Dialictus) laevissimum (Smith)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 170-175

Lasioglossum (Dialictus) laevissimum (Smith)

( Figures 132A–C , 133A–F )

Halictus laevissimus Smith, 1853: 72 . ♀.

Holotype. ♀ Canada, Manitoba, Arctic America. South of Lake Winnipeg , [ BMNH: B.M. Type 17a 1002]. Examined.

Halictus levissimus Dalla Torre, 1896: 68 (Emend.)

Halictus smilacinae Robertson, 1897: 322 . ♀.

Lectotype. ♀ USA, Illinois, Carlinville (C. Robertson); [ INHS: 179618] by W.E. Laberge.

Halictus euryceps Ellis, 1914: 98 . ♀.

Syntypes. ♀ USA, New Mexico, Beulah, end of August , (Cockerell); [ CAS: 15605] ; ♀ USA, New Mexico, Beulah , 27.vii., nesting (Cockerell), [ MCZ: 13810] ; ♀ USA, New Mexico, Beulah [ ANSP]. Examined .

Halictus (Chloralictus) phaceliarum Cockerell, 1919: 299 . ♀. [new synonymy]

Holotype. ♀ USA, Colorado, Peaceful Valley , Colorado, 26.viii.1918 (W.P. Cockerell); [ NMNH: 40260]. Examined.

Halictus (Chloralictus) praepes Sandhouse, 1924: 30 . ♂. [new synonymy]

Holotype. ♂ USA, Colorado, Peaceful Valley , 1919 (Cockerell); [ NMNH: 26430]. Examined.

Halictus (Chloralictus) astutus Sandhouse, 1924: 31 . ♂. [new synonymy]

Holotype. ♂ USA, New Mexico, Beulah, 18.viii. (W. Porter); [ NMNH: 26431]. Examined.

Halictus (Chloralictus) abundus Sandhouse, 1924: 32 . ♂. [new synonymy]

Holotype. ♂ USA, New Mexico, Beulah , end of viii (Cockerell); [ NMNH: 26432]. Examined.

Halictus (Chloralictus) tranquillus Sandhouse, 1924: 32 . ♂. [new synonymy]

Holotype. ♂ USA, New Mexico, Santa Fe , vii (Cockerell); [ NMNH: 26433]. Examined.

Halictus (Chloralictus) jameseae Cockerell, 1933: 41 . ♂. [new synonymy]

Holotype. ♂ USA, Colorado, Pingree Park , 15.viii.1932, (H. James); [ CAS: 15610]. Examined.

Dialictus solidaginis Mitchell, 1960: 443 . ♂. [new synonymy]

Holotype. ♂ USA, Michigan, Marquette Co., 20.vi.1955 ( R. R. Dreisbach); [ NCSU]. Examined.

Taxonomy. Robertson, 1902: Chloralictus smilacinae , p. 249 (key); Cockerell, 1905: Halictus laevissimus ♀, p. 351 (tax. notes); Michener, 1951: Lasioglossum (Chloralictus) abundus , p,. 1111, L. (C.) astutus p. 1112, L. (C.) jameseae , p. 1114, L. (C.) laevissimum , p. 1114, L. (C.) phaceliarum , p. 1116, L. (C.) praepes , p. 1116, L. (C.) tranquillum, p. 1118 (catalogue); Mitchell, 1960: Dialictus laevissimus ♀ (♂ misdet.), p. 401 (redescription); Knerer & Atwood, 1962: Dialictus laevissimus ♂, p. 1228 (description); Krombein, 1967: Lasioglossum (Dialictus) laevissimum , p. 464, L. (D.) solidaginis , p. 466 (catalogue); Hurd, 1979: Dialictus abundus , p. 1963, D. astutus , p. 1964, D. jameseae , p. 1967, D. phaceliarum , p. 1970, D. praepes , p. 1970, D. solidaginis , p. 1971, D. tranquillus , p. 1972 (catalogue); Moure & Hurd, 1987: Dialictus abundus , p. 87, D. astutus , p. 91, D. jameseae , p. 109, D. phaceliarum , p. 121, D. praepes , p. 124, D. solidaginis , p. 130, D. tranquillus , p. 135 (catalogue).

Diagnosis. Females of L. laevissimum can be recognised by the diagnostic combination of a large size (5.1–7.1 mm), wide head (length/width 0.89–0.95), gena often wider than eye especially in larger individuals, mesoscutal punctures sparse on central disc (i=1–3d), mesepisternum rugulose, metapostnotum incompletely striate, T1 acarinarial fan small but complete or with narrow dorsal opening, blackish brown metasomal terga with apical halves impunctate (except along premarginal line) and T3 usually with a sharply contrasted basal band of white tomentum. They are similar to L. pacatum and L. marinense . Female L. pacatum have moderately elongate head (length/width ratio = 0.96–1.00) and the gena narrower than the eye. Female L. marinense have virtually no tomentum on the metasomal terga and the gena narrower than the eye.

Males of L. laevissimum can be recognised by their large size (5.4–6.7 mm), face with dense tomentum limited to lower paraocular area, elongate flagellomeres (length/width ratio = 1.64–2.00), moderately polished mesoscutum due to weak microsculpture, rugulose mesepisternum with obscure punctures on ventral portion, and apical impressed areas of the metasomal terga impunctate. They are most similar to L. ephialtum which have the mesoscutum dull due to microsculpture.

Redescription. FEMALE. Length 5.12–7.10 mm; head length 1.34–1.85 mm; head width 1.51–2.02 mm; forewing length 4.15–5.19 mm.

Colouration. Head and mesosoma pale blue or green with golden reflections. Clypeus with apical half blackish brown and basal half, and supraclypeal area with brassy reflections. Antenna dark brown, flagellum with ventral surface reddish brown. Tegula reddish brown. Wing membrane subhyaline, venation and pterostigma amber. Legs brown, tarsi reddish brown. Metasoma blackish brown, terga and sterna with apical margins brown

Pubescence. Dull white. Sparse. Head and mesosoma with moderately dense woolly hairs (1–1.5 OD), longest on genal beard, metanotum and mesopleuron (2–2.5 OD). Paraocular area with sparse subappressed hairs. Gena with sparse tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with sparse, fine setae. T1 acarinarial fan with small dorsal opening. T2 basolateral area with appressed tomentum. T3 typically with distinct basal band of white tomentum. T4–T5 with scattered tomentum partially obscuring surface.

Surface sculpture. Face imbricate, punctation fine. Clypeus with apical half polished, punctation moderately sparse (i=1–3d). Supraclypeal area with punctation moderately sparse (i=1–4d). Lower paraocular and antennocular areas with punctation moderately dense (i=1–1.5d). Upper paraocular area and frons punctatereticulate. Ocellocular area punctate (i=1–1.5d). Gena and postgena lineolate. Mesoscutum imbricate, posterior portion polished, punctation fine, moderately sparse between parapsidal lines (i=1–3d), dense laterad of parapsidal lines (i>=d), contiguous on anterolateral portions. Mesoscutellum similar to mesoscutum, submedial punctation sparse (i=1–4d). Axilla punctate. Metanotum ruguloso-imbricate. Preëpisternum rugulose. Hypoepimeral area weakly rugulose. Mesepisternum dorsal half weakly rugose, ventral half imbricate. Metepisternum with dorsal third rugoso-striate and ventral portion imbricate. Metapostnotum incompletely rugoso-striate, medial striation distinctly longer than submedial striations, posterior margin imbricate. Propodeum with dorsolateral slope rugose, lateral and posterior surfaces imbricate. Metasomal terga polished except apical impressed areas weakly coriarious, punctation on basal halves moderately sparse (i=1.5–2d), apical half impunctate (except along premarginal line).

Structure. Head very wide (length/width ratio = 0.89–0.95). Eyes weakly convergent below (UOD/LOD ratio = 1.08–1.17). Clypeus ½ below suborbital tangent, apicolateral margins strongly convergent. Antennal sockets close (IAD/OAD <0.5). Frontal line carinate, ending 2 OD below median ocellus. Gena wider than, or equal to, eye. Inner metatibial spur pectinate with 3–5 teeth. Metapostnotum moderately elongate (MMR ratio = 1.19–1.30), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina moderately strong, lateral carina moderately strong, nearly reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.43– 6.70 mm; head length 1.49–1.85 mm; head width 1.54–1.87 mm; forewing length 4.09–5.06 mm.

Colouration. Flagellum with ventral surface reddish orange to yellow-orange. Wing membrane subhyaline, venation and pterostigma dark amber to brown. Tarsi reddish to yellow-orange.

Pubescence. Lower paraocular area with dense tomentum obscuring most of surface. Clypeus, and supraclypeal area with scattered tomentum not obscuring surface. S2–S4 with dense posteriorly directed hairs which are absent along the midline.

Surface sculpture. Mesepisternal punctation distinct on ventral portion. Metapostnotum coarsely rugose. Propodeum with lateral and posterior surfaces coarsely rugose. Metasomal terga punctation coarse, apical impressed area impunctate.

Structure. Head moderately wide (length/width ratio = 0.97–0.99). Eyes strongly convergent below (UOD/LOD ratio = 1.45–1.54). Antennal sockets distant (IAD/OAD> 1.5). Frontal line carinate, ending 1.5 OD below median ocellus. Pedicel shorter than F1. F2 length 2.0X F1. F2–F10 elongate (length/width ratio = 1.64–2.00). Metapostnotum moderately elongate (MMR ratio = 1.21–1.30), posterior margin rounded or weakly angled onto posterior surface.

Terminalia . S7 with median lobe clavate, apex rounded ( Fig. 133F ). S8 with apicomedial margin weakly convex ( Fig. 133F ). Genitalia as in Fig. 133D–E . Gonobase with ventral arms narrowly separated. Gonostylus small, dorsal setae elonagate. Retrorse lobe moderately elongate, attenuated apically.

Range. Nova Scotia west to British Columbia, south to New Mexico ( Fig. 129 ).

Additional material examined. CANADA: ALBERTA: 3♂♂ 15 km S Three Hills, Hwy 21, N51.49484 W113.23214, 702 m, 2.ix.2007 (Gibbs & Sheffield); [ PCYU] ; 7♀ 6♂♂ Edmonton , 30.viii.1984 (Thormin, Spanton & Nicholson); [ PMAE] ; BRITISH COLUMBIA: 2♀ Aldergrove , 50–100 m, 3.vii.1978 (N.L.H. Krauss); [ AMNH] ; 1♀ Cowichan Lake Forestry Station, Ministry of Forests, Mesachie Lake , N48°49´07.9´´ W124°08´05.1´´, 11.v.2005 (E. Elle) ; 1♀ Cowichan Lake Forestry Station, Ministry of Forests, Mesachie Lake , N48°49´07.9´´ W124°08´05.1´´, 13.vii.2005 (E. Elle) ; NEW BRUNSWICK: 1♀ Kent Co., St. Ignace , 15.viii.2005 (A.I. Gravel) ; 2♀ Kent Co., St. Ignace , N46.707 W071.054, 31.vii.2005 (M. Gravel); [ PCYU] ; NORTHWEST TERRITORIES: 4♂♂ Mackenzie Dist., Norman Wells , N65°15ʹ15ʹʹ W126°41ʹ15ʹʹ, 22.viii– 1.ix.2005 (D. Currie & R. Popko); [ ROM] ; NOVA SCOTIA: 1♀ Kings Co., Avonport , N45.1198 W064.273, 28.ix.2002 (C. Sheffield) ; 1♀ Kings Co., Avonport , N45.1198 W064.273, 29.ix.2002 (C. Sheffield) ; 1♀ Kings Co., Lakeville , N45.113 W065.5849, 8.vi.2003 (Sheffield, Rigby & Jansen); [ PCYU] ; ONTARIO: 1♀

Ottawa, 26.iv.1916 (F.W.L. Sladen); [CNC]; 1♀ York University, N43.772 W079.497, 24.v.2006 (J. Gibbs); 1♀ York University, N43.772 W079.497, 26.vi.2006 (J. Gibbs); PRINCE EDWARD ISLAND: 1♀ Queens Co., 6.vii.2006 ( V. MacPhail); 2♀ Queens Co., 7.vii.2006 ( V. MacPhail); 1♀ Queens Co. , 8.vii.2006 ( V. MacPhail); [ PCYU] ; SASKATCHEWAN: 1♀ Saskatoon , 28.vii.1977 (N.L.H. Krauss); [ AMNH]; USA : COLORADO: 2♀ Park Co., 13 km N Eleven Mile S.P., N38.99079 W105.42997, 2671 m, 30.vii.2007 (Gibbs & Sheffield); [ PCYU] ; MAINE: 6♀ Acadia, Gt. Pond, 18.vii.1978 (P.E. Hallett); [ PHPC]; MARY- LAND: 2♀ Garrett Co., N39.3097 W079.4577, (S.W. Droege) ; MICHIGAN: 1♀ Allegan Co., N42.5538 W086.0437, 28.viii.2003 (S.W. Droege) ; NEW MEXICO: 1♀ Otero Co., Cloudcroft, 8500ft, 31.vii.1972, (G.C. Eickwort); [ CUIC] ; NORTH CAROLINA: 2♀ Swain Co., Great Smoky Mtn. N.P., Andrew’s Bald , N35.5396 W083.4942, 6.viii.2006 (J. Gibbs); [ GSNP] ; OHIO: 1♀ near Cuyahoga Valley N.P., N41.24065 W081.54465, 16.viii.2006 (J. Gibbs) ; UTAH: 1♀ San Juan Co., La Sal Mtns., Warner Lk., 9400 ft., 29.vi.1999; [ PCYU] .

Floral records. LINACEAE : Linum lewisii , ROSACEAE : Amelanchier, Cratategus , Fragaria , Potentilla , Prunus , Rosa , Rubus , ASTERACEAE : Anaphalis , Antennaria , Aster , Hieracium , Rudbeckia , Senecio , Solidago canadensis , S. velutina , Taraxacum , APOCYNACEAE : Apocynum , BRASSICACEAE : Barbarea , Berteroa , RHAMNACEAE : Ceanothus , RANUNCULACEAE : Clematis , CORNACEAE : Cornus , THYME- LAEACEAE: Dirca palustris , ONAGRACEAE : Epilobium , POLYGONACEAE : Fagopyrum , GENTIAN- ACEAE: Frasera , APIACEAE : Heracleum maximum , HYRANGEACEAE: Hydrangea , FABACEAE : Medicago , Melilotus , Trifolium , HYDROPHYLLACEAE : Phacelia , POLEMONIACEAE : Polemonium aff. caeruleum , ANACARDIACEAE : Rhus , SALICACEAE : Salix , LILIACEAE : Maianthemum stellatum .

Biology. Brittain, 1933: (pollination as smilacinae ); Evans & Lin, 1959: (predator, as euryceps ); Knerer & Atwood, 1962: (nest site, geography, floral records); Evans, 1964: (predator); Knerer & Atwood, 1967: (parasite); Evans, 1970: (predators); Alcock, 1974: (predators); Delfinado & Baker, 1976: (mite association); Batra, 1987: (ethology); Packer, 1992: (social organization); Packer & Owen, 1994: (relatedness, sex ratio).

Comments. Common. The male of L. laevissimum has been described under different names several times. Mitchell (1960) incorrectly associated the sexes of this species but Knerer and Atwood (1962a) remedied the situation. The extensive size variation and widespread abundance of this species are two factors which have contributed to the numerous synonymies for this species.

Figures

FIGURE 129. Distribution of Lasioglossum incompletum (medium grey), L. knereri (dark grey), and L. laevissimum (light grey).

FIGURE 132. Lasioglossum laevissimum (Smith). Female (A) lateral habitus; (B) dorsal habitus; (C) face. Scale bars, A–C = 1 mm.

FIGURE 133. Lasioglossum laevissimum (Smith). Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) ventral view of genital capsule; (E) dorsal view of genital capsule; (F) S7, S8. Scale bars, A–C = 1 mm, F = 0.5 mm.