Lasioglossum (Dialictus) viridatum (Lovell)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 351-355

Lasioglossum (Dialictus) viridatum (Lovell)

( Figures 236A–D , 237A–F )

Halictus viridatus Lovell, 1905b: 300 . ♀ ♂.

Lectotype. ♀ USA, Maine, Waldoboro , vi, [ NMNH: 71574] by T. B. Mitchell. Examined.

Dialictus lepidus Mitchell, 1960: 438 . ♂.

Holotype. ♂ USA, Michigan, Keweenaw Co., 27.viii.[year obscured] ( R. R. Dreisbach); [ NCSU]. Examined.

Taxonomy. Michener, 1951: Lasioglossum (Chloralictus) viridatum , p. 1118 (catalogue); Mitchell, 1960: Dialictus viridatus ♀, p. 430 (redescription); Mitchell, 1962: Dialictus viridatus , p. 547 (synonymy); Krombein, 1967: Lasioglossum (Dialictus) viridatum , p. 466 (catalogue); Dialictus viridatus , p. 1973 (catalogue); Moure & Hurd, 1987: Dialictus viridatus , p. 139 (catalogue).

Diagnosis. Females of L. viridatum can be recognised by the diagnostic combination of a round head (length/width ratio = 0.94–0.96), imbricate mesoscutum with moderately coarse punctures that are moderately sparse on central disc (i=1–2d), reddish brown tegula, strongly rugose mesepisternum, metapostnotum rugoso-striate reaching the posterior margin ( Fig. 236D ), T1 acarinarial fan with dorsal opening, brown metasomal terga with apical halves obscurely punctate, and T4 with sparse tomentum partially obscuring surface. They are most similar to L. atwoodi which has the metapostnotal rugae almost but not reaching the posterior margin and T4 with only scattered tomentum not obscuring surface.

Males of L. viridatum are similar to females but may be further distinguished by the moderately elongate head (length/width ratio = 1.01–1.02), elongate flagellomeres (length/width ratio = 1.56–1.64), nearly reticulate anterolateral portions of mesoscutum, brownish yellow tarsi, apical impressed areas of the metasomal terga impunctate, and apicolateral portions of S3–S5 with moderately dense plumose hairs.

Redescription. FEMALE. Length 5.49–6.22 mm; head length 1.46–1.58 mm; head width 1.56–1.66 mm; forewing length 3.90–4.33 mm.

Colouration. Head and mesosoma green with faint golden or bluish reflections. Clypeus with apical half blackish brown and basal half, and supraclypeal area golden. Antenna dark brown, flagellum with ventral surface reddish brown, F8–F10 sometimes orange-yellow. Tegula reddish to pale translucent amber. Wing membrane subhyaline, venation and pterostigma pale amber to brownish yellow. Legs brown, medio- and distitarsi reddish brown. Metasoma dark brown, terga and sterna with apical margins translucent brownish yellow.

Pubescence. Dull white. Moderately sparse. Head and mesosoma with moderately dense woolly hairs (1– 1.5 OD), longest on genal beard, metanotum and mesopleuron (2–2.5 OD). Lower paraocular area and gena with sparse tomentum not obscuring surface. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with moderately dense, fine setae. T1 acarinarial fan with wide dorsal opening, equal to width of lateral hair patches. T2 basolaterally and T3–T5 entirely with scattered tomentum not obscuring surface. T2 apicolateral and T3–T4 apical margins with very sparse fringes.

Surface sculpture. Face weakly imbricate, punctation moderately strong. Clypeus with apical half polished, punctation moderately sparse (i=1–2d). Supraclypeal area with punctation moderately sparse (i=1–2d). Lower paraocular area punctation dense (i≤d). Antennocular area punctation moderately dense (i≤1.5d). Upper paraocular area and frons reticulate-punctate. Ocellocular area minutely punctate (i≤d). Gena lineolate. Postgena polished, faintly lineolate. Mesoscutum weakly tessellate-imbricate, punctation moderately coarse and deep, sparse anteromedially (i=2–3d), moderately sparse between parapsidal lines (i=1–2d), dense laterad of parapsidal line (i≤d), and reticulate on anterolateral portions. Mesoscutellum similar to mesoscutum, submedial punctation sparse (i=1.5–4d). Axilla punctate. Metanotum imbricate. Preëpisternum rugose. Hypoepimeral area ruguloso-imbricate. Mesepisternum rugose. Metepisternum with dorsal half rugoso-striate, ventral half imbricate. Metapostnotum completely rugoso-striate, reaching posterior margin. Propodeum with dorsolateral slope and lateral surface weakly ruguloso-imbricate, posterior surface tessellate above, rugulose below. Metasomal terga polished except margins faintly coriarious, punctation moderately sparse punctures on basal halves (i=1.5–3d), obscure on apical half, T1 dorsal surface and T2 apical impressed area virtually impunctate.

Structure. Head wide (length/width ratio = 0.94–0.96). Eyes convergent below (UOD/LOD ratio = 1.21– 1.23). Clypeus ½ below suborbital tangent, apicolateral margins convergent. Antennal sockets close (IAD/ OAD <0.5). Frontal line carinate, ending 2.5 OD below median ocellus. Gena narrower than eye. Inner metatibial spur pectinate with 3–4 teeth. Metapostnotum moderately elongate (MMR ratio = 1.19–1.30), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina weak, linear, lateral carina divergent, nearly reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.12– 5.67 mm; head length 1.48–1.67 mm; head width 1.46–1.66 mm; forewing length 3.72–4.27 mm.

Colouration. Labrum reddish brown. Mandible orange. Flagellum with ventral surface orange-yellow. Tibial apices, and metatibial base and tarsi orange to yellowish brown.

Pubescence. Face below eye emargination with moderately dense tomentum partially obscuring surface. Lower paraocular area with dense tomentum obscuring surface. Gena without tomentum. S3–S5 apicolateral portions with moderately dense plumose hairs.

Surface sculpture. Mesoscutum anterolateral portion reticulate-rugose. Hypoepimeral area rugose. Metepisternum with dorsal two thirds rugoso-striate. Propodeum dorsolateral slope, and lateral and posterior surface strongly rugose. Metasomal terga apical halves impunctate (except along premarginal line).

Structure. Head moderately elongate (length/width ratio = 1.01–1.02). Eyes strongly convergent below (UOD/LOD ratio = 1.54–1.63). Clypeus 2/3 below suborbital tangent, apicolateral margins weakly convergent. Antennal sockets distant (IAD/OAD> 1.4). Frontal line carinate, ending 1.5 OD below median ocellus. IOD subequal to OOD. Pedicel shorter than F1. F2 length 1.8X F1. F2–F10 moderately elongate (length/ width ratio = 1.56–1.64). Metapostnotum moderately elongate (MMR ratio = 1.25–1.29), posterior margin sharply angled onto posterior surface.

Terminalia . S7 with medial lobe columnar, apex truncate ( Fig. 237F ). S8 with apicomedial margin strongly convex ( Fig. 237F ). Genitalia as in Fig. 237D–E . Gonobase with ventral arms narrowly separated. Gonostylus small, slender, dorsal setae elongate. Retrorse lobe short, attenuated apically.

Range. Nova Scotia west to Manitoba, south to North Carolina ( Fig. 235 ).

Additional material examined. CANADA: MANITOBA: 2♀ Tallgrass Prairie Preserve , N49.147 W096.6803, 312 m . 11.vi.2007 (Boudreault & Goulet); NEW BRUNSWICK: 1♀ Kent Co., St. Ignace , N46.707 W071.054, 31.vii.2005 (M. Gravel) ; NOVA SCOTIA: 4♀ Annapol. Co., Middleton , N44.9665 W065.5755, 11.vii.2002 (C. Sheffield) ; 1♀ Hants Co., Upper Rawdon , N45.0845 W063.7297, 10.vii.2003 (Sheffield, Rigby & Jansen); [ PCYU] ; ONTARIO: 1♀ Flesherton, R . Saugeen , 3.v.1980 (P.E. Hallet) ; 1♀ Flesherton, R . Saugeen , 12.vi.1983 (P.E. Hallet) ; 1♀ Flesherton, R . Saugeen , 2.vi.1985 (P.E. Hallet) ; 1♂ Flesherton, R . Saugeen , 18.vii.1988 (P.E. Hallet) ; 2♂♂ Flesherton, R . Saugeen , 19.vii.1988 (P.E. Hallet); [ PHPC] ; 1♀ Haliburton-Highlands, Plowright Farm , 29.v.1985 (L. Packer); [ PCYU] ; 15♀ 1♂ Metcalf,

29.vii.1983 (B.E. Cooper); [ PMAE]; USA: INDIANA: 1♀ Lake Co., Indiana Dunes NL, Miller Woods , N41°36´26´´ W087°17´09´´ , 5.vi.2003 ( R. Grundel ); MICHIGAN: 1♀ Allegan Co., 3 mi WSW Fennville , 25.v.2005 (J.K Tuell et al.); 1♀ Allegan Co., 2 mi ESE Douglas , 31.v.2006 (J.K Tuell et al.); [ PCYU]; NEW HAMPSHIRE: 2♀ Nelsen [ ANSP] ; NEW YORK: 1♀ Tompkins Co., Hemlock Grv, Danby , 12.v.2009 (M.G. Park); [ CUIC]; NORTH CAROLINA: 1♀ Great Smoky Mountain N. P., Cataloochee , N35.62813 W083.09997 , 6.viii.2006 (J. Gibbs); [ GSNP] .

Floral records. APOCYNACEAE : Apocynum , ARALIACEAE : Aralia , ASCLEPIADACEAE : Asclepias , ASTERACEAE : Anaphalis , Aster , Cichorium , Epilobium , Eupatorium , Leontodon , Solidago , Taraxacum , BRASSICACEAE : Barbarea , Brassica , CAPRIFOLIACEAE : Diervilla , ERICACEAE : Rhododendron , Vaccinium , FABACEAE : Melilotus , POLYGONACEAE : Rheum , PRIMULACEAE : Lysimachia terrestris , ROSACEAE : Amelanchier , Geum , Malus sylvestris , Prunus , Rubus , SALICACEAE : Salix .

Biology. Lovell, 1908: (flower records); Reinhard, 1924: (predator); Atwood, 1933: (nest sites, nest architecture, guard behaviour, life history, parasites).

Comments. Uncommon.

Figures

FIGURE 235. Distribution of Lasioglossum vierecki (light grey) and L. viridatum (dark grey).

FIGURE 236. Lasioglossum viridatum (Lovell). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) metapostnotum. Scale bars, A–C = 1 mm.

FIGURE 237. Lasioglossum viridatum (Lovell). 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.