Lasioglossum (Dialictus) subversans (Mitchell)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 309-313

Lasioglossum (Dialictus) subversans (Mitchell)

( Figures 213A–D , 214A–G )

Dialictus subversans Mitchell, 1960: 419 . ♀.

Holotype. ♀ USA, Michigan, Otsego Co., 26.iv.1944 ( R. R. Dreisbach); [ NCSU]. Examined.

Dialictus perpunctatulus Knerer and Atwood, 1966a: 884 . ♀ ♂. [new synonymy]

Holotype. ♀ CANADA, Ontario, Arctic Watershed, Timiskaming District , 21.vi.1961 on Fragaria, (G. Knerer) ; [ ROM: 83912]. Examined.

Taxonomy. Krombein, 1967: Lasioglossum (Dialictus) subversans , p. 466 (catalogue); Dialictus perpunctatulus , p. 1970, D. subversans , p. 1972 (catalogue); Moure & Hurd, 1987: Dialictus perpunctatulus , p. 121, D. subversans , p. 132 (catalogue).

Diagnosis. Females of L. subversans can be recognised by the diagnostic combination of a wide head (length/width ratio = 0.94–0.97), strongly brassy supraclypeal area, imbricate mesoscutum with moderately dense punctures on centre of disc (i=1–1.5d), distinct but irregular mesepisternal punctures, weak longitudinal rugae on metapostnotum not reaching rounded posterior margin ( Fig. 213D ), and brown metasomal terga with sparse tomentum and very obscure apical punctures. They are most similar to L. knereri and L. foveolatum . Female L. knereri have the mesoscutum polished due to lack of microsculpture. Female L. foveolatum have a strongly convex supraclypeal area and very strong parapsidal lines.

Males of L. subversans and L. knereri can be distinguished from all other Canadian Dialictus by the very long and dense scopa-like hairs on S2–S3 and apicolateral portions of S4–S5 ( Fig. 214D ). They may be distinguished by the apical impressed areas of the metasomal terga which are impunctate in L. subversans but distinctly punctate in L. knereri .

Redescription. FEMALE. Length 4.88–5.19 mm; head length 1.32–1.44 mm; head width 1.40–1.49 mm; forewing length 3.66–3.72 mm.

Colouration. Head and mesosoma greenish blue. Mandibles orange to yellow, apex red, base blackish brown. Clypeus with apical 2/3 blackish brown and basal portion, and supraclypeal area strongly bronzed. Antenna dark brown, flagellum with ventral surface reddish brown. Tegula reddish amber. Wing membrane subhyaline, venation and pterostigma brownish yellow. Legs brown, medio- and distitarsi ferruginous. 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). Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with sparse, fine setae. T1 acarinarial fan sparse with dorsal opening nearly equal to lateral hair portions. T2–T4 with extremely sparse basolateral tomentum. T3–T4 apical margins with very sparse, virtually absent, fringes.

Surface sculpture. Face imbricate, punctation moderately strong. Clypeus with apical half polished, punctation moderately sparse (i=1–2.5d). Supraclypeal area with punctation sparse (i=1–3d). Lower paraocular area punctation dense (i≤d). Antennocular area moderately dense (i=1–1.5d). Upper paraocular area and frons reticulate. Ocellocular area densely, minutely punctate (i≤d). Gena and postgena lineolate. Mesoscutum polished, weakly imbricate, punctation moderately strong, moderately dense between parapsidal lines (i=1–1.5d), dense laterad of parapsidal line (i≤d), and reticulate on anterolateral portions. Mesoscutellum polished, submedial punctation sparse (i=1–4d). Axilla minutely punctate. Metanotum imbricate. Preëpisternum rugulose. Hypoepimeral area weakly rugulose. Mesepisternum dorsal half weakly rugulose, punctation obscure (i≤d), ventral half imbricate, punctation more evident (i=1–2d). Metepisternum with dorsal third rugulose-striate and ventral portion imbricate. Metapostnotum incompletely rugoso-striate, posterior margin imbricate. Propodeum with dorsolateral slope and lateral surface weakly rugulose, posterior surface tessellate above, rugose below. Metasomal terga polished except apical impressed areas weakly coriarious, punctation on basal halves fine (i=1.5–2d), sparse on apical halves (i=2–6d), virtually impunctate (except along premarginal line).

Structure. Head wide (length/width ratio = 0.94–0.97). Eyes convergent below (UOD/LOD ratio = 1.23– 1.27). Clypeus ½ below suborbital tangent, apicolateral margins convergent. Supraclypeal area weakly convex. Antennal sockets close (IAD/OAD <0.5). Frontal line carinate, ending 2.5 OD below median ocellus. Gena narrower than eye. Parapsidal lines linear, obscure. Inner metatibial spur pectinate with 2–4 teeth. Metapostnotum truncate (MMR ratio = 1.20–1.40), posterior margin narrowly rounded onto posterior surface. Propodeum with oblique carina weak, lateral carina divergent, almost meeting weak.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 4.58– 5.31 mm; head length 1.31–1.39 mm; head width 1.33–1.42 mm; forewing length 3.23–3.29 mm.

Colouration. Flagellum with ventral surface orange to reddish brown.

Pubescence. Clypeus with sparse tomentum. Lower paraocular area with dense tomentum. Gena without tomentum. S2–S3 and S4–S5 apicolateral portions with very dense scopa-like hairs (1.5–2.5 OD).

Surface sculpture. Metapostnotum completely rugoso-striate. Metasomal terga strongly punctate, apical impressed areas impunctate.

Structure. Head wide (length/width ratio = 0.96–0.98). Eyes strongly convergent below (UOD/LOD ratio = 1.33–1.48). Clypeus 2/3 below suborbital tangent, apicolateral margins subparallel. Antennal sockets distant (IAD/OAD> 1.1). Frontal line carinate, ending 2 OD below median ocellus. IOD subequal to OOD. Pedicel subequal to F1. F2 length 1.7–1.9X F1. F2–F10 moderately short (length/width ratio = 1.36–1.67). Metapostnotum moderately elongate (MMR ratio = 1.10–1.32), posterior margin sharply angled onto posterior surface.

Terminalia . S7 with median lobe elongate, slender, clavate, apex rounded ( Fig. 214G ). S8 with apicomedial margin weakly convex ( Fig. 214G ). Genitalia as in Fig. 214E–F . Gonobase short relative to gonocoxite, ventral arms narrowly separated. Gonostylus small, dorsal setae elongate. Retrorse lobe short, wide.

Range. Nova Scotia to British Columbia, Michigan ( Fig. 212 ).

Additional material examined. CANADA: BRITISH COLUMBIA: 1♀ 4.vii.2002; [ PCYU] ; NEW BRUNSWICK: 1♀ Kouchibougac N.P., 13.vi.1977 (S.J. Miller); [ CNC] ; 1♂ Kouchibougac N.P., 3.viii.1977 (S.J. Miller); [ PMAE] ; NOVA SCOTIA: 1♂ Digby Co., Briar Is. , N44.2354 W66.3698, 2.viii.2002 (C. Sheffield & S. Rigby) ; 2 ♀ Kings Co., Wst. Blk. Rck. , N45.1298 W064.7383, 21.vi.2002 (C. Sheffield) ; 1♀ Kings Co., near Grafton , N45.0869 W064.6677, 31.vii.2002 (C. Sheffield); [ PCYU] ; ONTARIO: 1♂ paratype Hearst , 13.viii.1962 (G. Knerer) ; 1♀ paratype Red Lake , 15.viii.1962 (G. Knerer); [ CNC] ; 1♂ 8 th Line Rd., Gloucester , 30.vi–5.vii.1977 ; 1♀ Constance Bay ,, 5–8.vii.1979 (M. Sanborne); [ PMAE] ; 1♀ Dorset P.S., 12.v.1961 (G. Knerer); 1♂, Dorset P.S., 19.vii.1961 (G. Knerer); 1♂ Dorset P.S., 20.vii.1961 (G. Knerer); 1♀ Kabinakagami R ., 12.viii.1963 (G. Knerer); 2♂♂ Upsala , 14.viii.1962 (G. Knerer); [ ROM] ; 1♀ Metcalf , 29.vii.1983 (B.E. Cooper); [ PMAE] ; SASKATCHEWAN: 2♀ Grassland Nat. Pk. , prairie, N49.0711 W106.52935, 830 m, 4.vi.2007 (Goulet, Boudreault & Fernandez); [ PCYU] .

Floral records. ASTERACEAE : Anaphalis , Aster , Solidago , FABACEAE : Melilotus , Trifolium , SALI- CACEAE: Salix .

Comments. Uncommon. This seems to be a boreal species.

Figures

FIGURE 212. Distribution of Lasioglossum sitocleptum (black), L. subversans (light grey), and L. subviridatum (dark grey).

FIGURE 213. Lasioglossum subversans (Mitchell). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) metapostnotum. Scale bars, A–C = 1 mm.

FIGURE 214. Lasioglossum subversans (Mitchell). Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) metasomal sterna; (E) ventral view of genital capsule; (F) dorsal view of genital capsule; (G) S7, S8. Scale bars, A–C = 1 mm, G = 0.5 mm.