Lasioglossum (Dialictus) lineatulum (Crawford)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 180-183

Lasioglossum (Dialictus) lineatulum (Crawford)

( Figures 137A–E , 138A–F )

Halictus lineatulus Crawford 1906: 5 . ♀.

Holotype. ♀ USA, Michigan, Ag. Coll., 5 October 1893 [10 May 1893] ( R. H. Wolcott); [ NMNH: 12071]. Examined.

Halictus subconnexus Ellis 1915: 291 . ♀.

Holotype. Unknown.

Halictus (Chloralictus) latus Sandhouse, 1924: 20 . ♀. [new synonymy]

Holotype. ♀ USA, Colorado, Colorado Springs, 20.iv., on willow (W.P. Cockerell), [ NMNH: 26414]. Examined. Halictus (Chloralictus) unicus Sandhouse, 1924: 21 . ♀.

Holotype. ♀ USA, Iowa, Seven miles east of Vinton , 29.vi.1922 (G. Sandhouse), [ NMNH: 26415]. Examined.

Taxonomy. Michener, 1951: Lasioglossum (Chloralictus) latum , p. 1114, L. (C.) lineatulum , p. 1114 (catalogue, Timberlake synonymy); Mitchell, 1960: Dialictus lineatulus ♂, p. 403, D. unicus ♂, p. 425 (redescription); Krombein, 1967: Lasioglossum (Dialictus) lineatulum , p. 464, L. (D.) unicum , p. 466 (catalogue); Hurd, 1979: Dialictus latus , p. 1967, D. lineatulus , p. 1968, D. unicus , p. 1972 (catalogue); Moure & Hurd, 1987: Dialictus latus , p. 110, D. lineatulus , p. 110, D. unicus , p. 136 (catalogue).

Diagnosis. Both sexes of L. lineatulum and L. novascotiae can be distinguished from other Canadian Dialictus by the sparse punctation of the mesoscutum including lateral portions ( Figs. 8A , 137D ), weakly rugose mesepisternum and weak oblique propodeal carina. Female L. lineatulum can be recognised by the round head (length/width ratio = 0.92–0.93), smooth dorsolateral slopes of propodeum ( Fig. 41A , 137E ) and faint metallic reflections on metasomal terga. Female L. novascotiae have a longer head (length/width ratio = 0.95–0.96), rugulose propodeal dorsolateral slopes ( Fig. 41B , 153D ) and blackish brown metasomal terga.

Male L. lineatulum can be recognised by the moderately dense plumose hairs across S2–S4 and laterally on S5. Male L. novascotiae have subappressed plumose hairs limited to apicolateral portions of S3 and lateral portions of S4–S5.

Redescription. FEMALE. Length 5.06–6.85 mm; head length 1.58–1.68 mm; head width 1.70–1.82 mm; forewing length 4.27–4.88 mm.

Colouration. Head and mesosoma blue to pale green, sometimes with golden reflections. Clypeus with apical half blackish brown and basal half, and supraclypeal area sometimes brassy. Antenna dark brown, flagellum with ventral surface dark brown to orange-brown. Tegula amber to reddish brown. Wing membrane subhyaline, venation and pterostigma pale honey-coloured. Legs brown, tibial bases, tarsi orange to reddish brown, metabasitarsus infused with brown. Metasoma dark brown, terga with faint green reflections on disc, apical margins reddish to translucent brownish yellow.

Pubescence. Dull white. Moderately dense. Head and mesosoma with moderately dense woolly hairs (1– 1.5 OD), longest on genal beard, metanotum and mesopleuron (2–2.5 OD). 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 dorsal opening. T2 basolaterally and T3–T4 entirely with tomentum partially obscuring surface. T2 apicolateral and T3–T4 apical margins with weak bands.

Surface sculpture. Face imbricate, punctation moderately strong. Clypeus polished, punctation sparse (i=1–4d). Supraclypeal area with punctation moderately sparse (i=1–4d). Lower paraocular and antennocular areas with punctation moderately dense (i=1–2d). Upper paraocular area and frons punctate-reticulate. Ocellocular area minutely punctate (i=d). Gena and postgena lineolate. Mesoscutum imbricate, posterior area of disc polished, punctation moderately strong, very sparse between parapsidal lines (i=1.5–5d), sparse laterad of parapsidal lines and on anterolateral portions (i=1–3d). Mesoscutellum similar to mesoscutum, submedial punctation sparse (i=2–5d). Axilla punctate. Metanotum imbricate. Preëpisternum weakly rugose. Hypoepimeral area rugulose. Mesepisternum dorsal portion weakly rugose, ventral portion rugulose-imbricate. Metepisternum with dorsal half striate, ventral half imbricate. Metapostnotum incompletely, strongly striate, medial striation distinct. Propodeum with dorsolateral slope imbricate-rugulose at posterior, lateral and posterior surfaces imbricate. Metasomal terga polished except basal and apical impressed areas faintly coriarious, punctation on basal halves moderately sparse (i=1.5–2d), apical halves sparse or impunctate (except along premarginal line).

Structure. Head wide (length/width ratio = 0.92–0.93). Eyes convergent below (UOD/LOD ratio = 1.18– 1.20). Clypeus 1/3 below suborbital tangent, apicolateral margins convergent. Antennal sockets close (IAD/ OAD <0.5). Frontal line carinate, ending 2 OD below median ocellus. Gena as wide as eye. Inner metatibial spur pectinate with 3–4 teeth. Metapostnotum moderately truncate (MMR ratio = 1.11–1.23), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina moderately strong, lateral carina nearly reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.49– 6.10 mm; head length 1.54–1.67 mm; head width 1.56–1.72 mm; forewing length 4.33–4.58 mm.

Colouration. Tegula dark reddish brown. Wing membrane subhyaline, venation and pterostigma dark amber. Tarsi orange to yellow.

Pubescence. Lower paraocular area with dense tomentum obscuring surface. Clypeus, and supraclypeal area with scattered tomentum not obscuring surface. S2–S3 apical portions and S4–S5 lateral portions with erect plumose hairs (1–1.5 OD).

Surface sculpture. Mesepisternum dorsal portion rugose. Metapostnotum coarsely and completely striate. Propodeum with lateral and posterior surfaces rugose. Metasomal terga punctation distinct, apical impressed area impunctate.

Structure. Head wide (length/width ratio = 0.94–0.97). Eyes strongly convergent below (UOD/LOD ratio = 1.48–1.52). Clypeus ½ below suborbital tangent, apicolateral margins subparallel. Antennal sockets distant (IAD/OAD> 1.1). Frontal line carinate, ending 1.5 OD below median ocellus. Pedicel subequal to F1. F2 length 1.6–1.8X F1. F2–F10 elongate (length/width ratio = 1.71–2.00). Metapostnotum moderately elongate (MMR ratio = 1.08–1.20), posterior margin sharply angled onto posterior surface.

Terminalia . S7 with median lobe columnar, apex rounded ( Fig. 138F ). S8 with apicomedial margin weakly convex ( Fig. 138F ). Genitalia as in Fig. 138D–E . Gonobase with ventral arms narrowly separated. Gonostylus small, dorsal setae elongate. Retrorse lobes elongate, rounded apically.

Range. Nova Scotia west to Manitoba, south to North Carolina ( Fig. 139 ).

Additional material examined. CANADA: ALBERTA: 1♀ 15 km S Three Hills, Hwy 21, N51.49484 W113.23214, 15.vi.2007 (Gibbs & Sheffield) ; MANITOBA: 2♀ YellowQuill Mxd. Grass Prairie Preserve, near Treesbank , N49°41´28´´ N099°34´29´´, 6.vi.2005 (A.M. Patenaude) ; 1♀ YellowQuill Mxd. Grass Prairie Preserve, near Treesbank , N49°40´51´´ N099°33´15´´, 25.vii.2005 (A.M. Patenaude) ; ONTARIO: 1♂ Huron Co., Pinery P.P., 14–23.viii.2005 (A. Taylor) ; 2♀ Norfolk Co., Pterophylla Plant Nursery , N42°38.404´W080°34.379´, 13–22.viii.2006 (P.J. Carson) ; 1♀ York University , N43.772 W079.497, 24.v.2006 (J. Gibbs) ; QUEBEC: 1♀ Saint Catherine , N46.85073 W071.61597 (L. Packer); [ PCYU] ; SASKATCHEWAN: 1♀ Saskatoon , 28.iv.1949 (A. R. Brooks); [ CNC] ; USA: MAINE: 1♂ Piscataquis Co., Milo , 14.viii.2006 (M.F. Veit) ; MARYLAND: 1♀ Garrett Co., N39.2992 W079.42 (S.W. Droege) ; MINNESOTA: 1♀ Clay Co., 4 mi E, 1 mi S Glyndon , 10.vi.2005 ( R. L.W.) ; 1♀ St. Paul, 394 & Penn , vi.2005 (L. Packer) ; NEW YORK: 1♀ Suffolk Co., 6.ix.2005 (S.W. Droege); [ PCYU] ; 1♀ Tompkins Co., Little Tree, Newfield , 9.v.2009 (M.G. Park); [ CUIC] ; NORTH CAROLINA: 1♂ Grandfather Mtn. , N36.08942 W081.83699, 13.viii.2006 (J. Gibbs) ; VERMONT: 1♂ Lamoille Co., Morristown , 4 mi S of Lake Elmore, 10.viii.2006 (M.F. Veit) ; WEST VIRGINIA: 1♀ Hampshire Co., N39.3314 W078.46, 24.v.2003 (S.W. Droege) ; 1♀ Hampshire Co., N39.3352 W078.4573, 14.vii.2003 (S.W. Droege); [ PCYU] ; WISCONSIN: 2♀ Door Co., N45.0783 W87.08685, 16.vi.2005 (C. Destree); [ ARC] .

Floral records. ANACARDIACEAE : Rhus , APOCYNACEAE : Apocynum , ASTERACEAE : Antennaria , Chrysanthemum , Erigeron , Krigia , Rudbeckia , Solidago , Taraxacum , BRASSICACEAE : Barbarea , CARYOPHYLLACEAE : Stellaria graminea , FABACEAE : Baptisia , Melilotus , HYDRANGEACEAE :

Hydrangea , LILIACEAE : Scilla , “ Smilacina ”, POLYGONACEAE : Fagopyrum , Polygonum , RHAMNA- CEAE: Ceanothus , ROSACEAE : Amelanchier , Crataegus , Fragaria , Malus , Potentilla , Prunus , Spiraea , SALICACEAE : Salix .

Biology. Evans & Lin, 1959: (predators); Knerer & Atwood, 1962: (floral records, nest sites, nest architecture); 1964: (metanotal anomaly); 1967: (parasites); Evans, 1975: (predator); Delfinado & Baker, 1976: (mite association); Ramberg et al., 1984: (karyotype); Eickwort, 1986: (social behaviour).

Comments. Common. A new species with affinities to L. lineatulum is known from Kansas and Missouri. Females of this new species have clear and abundant punctures on the apical impressed areas of T2–T3 and clearly separated punctures on the frons. DNA barcodes from one Kansas specimen of this species and fifteen L. lineatulum specimens show a minimum difference of 1.15%. In comparison, the maximum intra-specific difference among L. lineatulum sequences was 0.74%.

Figures

FIGURE 8. Mesoscutal punctation on lateral portion of disc (A) L. obscurum, (B) L. incompletum.

FIGURE 41. Dorsolateral slope of propodeum of female (A) L. lineatulum, (B) L. novascotiae.

FIGURE 137. Lasioglossum lineatulum (Crawford). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) mesoscutum; (E) mesepisternum. Scale bars, A–C = 1 mm.

FIGURE 138. Lasioglossum lineatulum (Crawford). 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.

FIGURE 139. Distribution of Lasioglossum lineatulum (light grey), and L. macroprosopum (dark grey).

FIGURE 153. Lasioglossum novascotiae (Mitchell). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) metapostnotum. Scale bars, A–C = 1 mm.