Lasioglossum (Dialictus) admirandum (Sandhouse)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 52-56

Lasioglossum (Dialictus) admirandum (Sandhouse)

( Figures 63A–D , 64A–G )

Halictus (Chloralictus) admirandus Sandhouse, 1924: 14 . ♀.

Holotype. ♀ USA, Woods Hole, Massachusetts (E. Cattell), [ NMNH: 26405]. Examined.

Dialictus perspicuus Knerer and Atwood, 1966a: 883 . ♀ ♂. [new synonymy]

Holotype. ♀ CANADA, Ontario, Iona , Elgin Co., 15.ix.1963 on Solidago, (G. Knerer) ; [ ROM: 83647]. Examined.

Taxonomy. Michener, 1951: Lasioglossum (Chloralictus) admirandum p. 1111 (catalogue); Mitchell, 1960: Dialictus admirandus ♀, p. 377 (redescription); Krombein, 1967: Lasioglossum (Dialictus) admirandum , p. 462 (catalogue); Hurd, 1979: Dialictus admirandus , p. 1963, D. perspicuus , p. 1970 (catalogue); Moure & Hurd, 1987: Dialictus admirandus , p. 88, D. perspicuus , p. 121 (catalogue).

Diagnosis. Females of L. admirandum can be recognised by the diagnostic combination of a moderately elongate head (length/width ratio = 0.95–1.01), densely tessellate mesoscutum with sparse punctures on centre of disc (i=1–3d), pale translucent brownish yellow tegula, weakly rugulose mesepisternum, incomplete rugae on metapostnotum, T1 acarinarial fan incomplete dorsally and metasomal terga polished, brown, with distinct punctures throughout and T3–T4 with abundant tomentum. Females of this species are most similar to L. paradmirandum and L. sagax . Female L. paradmirandum have the mesepisternum tessellate and declivitous portions of T1 distinctly coriarious. Female L. sagax have the apical half of T2 nearly impunctate.

Males of L. admirandum are similar to females but have longer heads (length/width ratio = 1.01–1.04) and may be further distinguished by a yellow band on the apex of the clypeus, abundant tomentum on face obscuring surface, elongate flagellomeres (length/width ratio = 1.57–1.82), extensive yellow on tibial apices and bases, and apical impressed areas of metasomal terga impunctate. Males of this species are most similar to L. sagax which differ in having the mesoscutum moderately polished due to weak microsculpture.

Redescription. FEMALE. Length 5.00– 6.50 mm; head length 1.51–1.63 mm; head width 1.55–1.69 mm; forewing length 3.97–4.45 mm.

Colouration. Head and mesosoma bluish green to blue. Clypeus with apical half blackish brown. Antenna dark brown, flagellum with ventral surface reddish brown. Mesoscutum golden green. Tegula brownish yellow to pale yellow. Wing membrane subhyaline, venation and pterostigma pale 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 dense. Head and mesosoma with moderately sparse woolly hairs (1– 2 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 plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with moderately sparse, fine setae. T1 acarinarial fan with wide dorsal opening, equal to width of lateral hair patches. T2 with basolateral and T3–T5 with moderately dense tomentum partially obscuring surface. T2 apicolateral and T3–T4 apical margins with weak fringes.

Surface sculpture. Face weakly imbricate, punctation moderately strong. Clypeus with apical half polished, punctation moderately sparse (i=1–3d). Supraclypeal area with punctation moderately dense (i=1–2d), medial line punctate. Lower paraocular area punctation dense (i≤d). Antennocular area punctation moderately dense (i=1–1.5d). Upper paraocular area and frons reticulate-punctate. Ocellocular area minutely punctate (i≤d). Gena lineolate. Postgena polished, weakly lineolate. Mesoscutum imbricate-tessellate, punctation moderately coarse and deep, sparse between parapsidal lines (i=1–3d), dense laterad of parapsidal line (i≤d), and punctate-reticulate on anterolateral portions. Mesoscutellum weakly imbricate, submedial punctation moderately sparse (i=1–2d). Axilla punctate. Metanotum ruguloso-imbricate. Preëpisternum weakly rugulose. Hypoepimeral area imbricate. Mesepisternum dorsal half weakly ruguloso-imbricate, ventral half imbricate, obscurely punctate. Metepisternum with dorsal third rugoso-striate, ventral portion imbricate. Metapostnotum incompletely rugoso-striate, posterior margin imbricate. Propodeum with dorsolateral slope and lateral surface weakly ruguloso-imbricate, posterior surface ruguloso-tessellate. Metasomal terga highly polished, very weakly coriarious, punctation on basal halves moderately dense (i=1–1.5d), sparse on apical halves (i=1.5–2.5d).

Structure. Head wide to round (length/width ratio = 0.95–1.01). Eyes convergent below (UOD/LOD ratio = 1.27). Clypeus 2/3 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 4 teeth. Metapostnotum moderately elongate (MMR ratio = 1.25), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina very weak, lateral carina weak, not reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.00– 6.10 mm; head length 1.45–1.63 mm; head width 1.44–1.55 mm; forewing length 3.54–3.90 mm.

Colouration. Labrum yellow. Mandible yellow, apex red, base blackish brown. Clypeus distal margin yellow. Flagellum with ventral surface reddish brown. Legs brown, protibia (sometimes all tibiae) yellow except anterior and posterior surface with brown patch; mesotibia yellow except outer surface mostly brown; metatibial base, apex and dorsal surface yellow; tarsi yellow.

Pubescence. Face below eye emargination moderately dense partially obscuring surface. Lower paraocular area with dense tomentum obscuring surface. S3 apicolateral and S4–S5 lateral portions with moderately dense plumose hairs (1–1.5 OD).

Surface sculpture. Clypeal punctation moderately dense (i=1–1.5d). Metanotum rugose. Mesepisternum dorsal half rugoso-reticulate. Metapostnotum completely rugoso-striate. Propodeum with dorsolateral slope rugose, lateral surface rugulose. Metasomal terga apical impressed areas impunctate.

Structure. Head moderately elongate (length/width ratio = 1.01–1.04). Eyes strongly convergent below (UOD/LOD ratio = 1.50–1.54). Antennal sockets distant (IAD/OAD> 1.1). Frontal line carinate, ending <2 OD below median ocellus. Pedicel shorter than F1. F2 length 1.8–2.0X F1. F2–F10 elongate (length/width ratio = 1.57–1.82). Metapostnotum moderately elongate (MMR ratio = 1.21–1.23), posterior margin weakly angled onto posterior surface.

Terminalia . S7 with median lobe clavate, apex rounded ( Fig. 64F ). S8 with apicomedial margin convex ( Fig. 64F ); genitalia as in Fig. 64D–E . Gonobase with ventral arms widely separated. Gonostylus small, dorsal setae elongate. Retrorse lobes elongate, attenuated and recurved apically.

Range. Ontario south to Maryland, west to Saskatchewan, Minnesota ( Fig. 65 ).

Additional material examined. CANADA: ONTARIO: 1♀ Frome , 17.ix.1961 (G. Knerer) ; 2♀ Frome , 15.ix.1963 (G. Knerer); [ ROM] ; 1♀ Gibbs Rd. , N45.47338 W074.18637, 7.x.2006 (Gibbs & Nozoe) ; 1♀ York University, Keele Campus, near Pond Rd. , 31.viii.2006 (E. Willis); [ PCYU] ; 2♀ Toronto , 13.vi.1963 (G. Knerer) ; 4♂♂ Toronto, D.M., 9.ix.1963 (G. Knerer); 2♂♂ Toronto, D.M., 11.ix.1963 (G. Knerer); 1♀ 1♂ paratypes, 5♀ Toronto, D.M., 16.ix.1963 (G. Knerer); [ PCYU; ROM] ; 1♂ paratype Caboconle , 14.viii.1961 (G. Knerer) ; 1♀ paratype Toronot , 5.viii.1962 (G. Knerer); [ CNC] ; SASKATCHEWAN: 1♀ N of Rocanville, Qu’Appelle R ., N50.5084 W101.7416, 454 m, 2.vi.2007 (Goulet, Boudreault & Fernandez); USA: MARY- LAND: 1♂ Pr. George’s Co., N39.0238 W076.9195 m 21–22.ix.2004 (N. Allen) ; 1♀ Pr. George’s Co., N39.0281 W076.92, 22.vii.2004 (N. Allen) ; MICHIGAN: 1♀ Tuscola , N43°31´W83°29´14 –18.vii (Tuell et al.) ; MINNESOTA: 1♀ Clay Co., 3 mi E, 2 mi S Felton , N47°02´44.2´´ N096°25´08.5´´, 21.vii.2006 ( R. L. Andres) ; 1♀ Clay Co., 3 mi E, 2 mi S Felton , N47°03´58.4´´ N096°26´58´´, 21.vii.2006 ( R. L. Andres); [ PCYU] ; WISCONSIN: 2♀ Brown Co., UWGB Sager Tract , N44.53348 W87.90562, 13.vi.2005 (J. Watson); [ ARC] .

Floral records. ANACARDIACEAE : Rhus , APIACEAE : Daucus , Eryngium , Oxypolis , Pastinaca , Ptilimnium , APOCYNACEAE : Apocynum , ASCLEPIADACEAE : Asclepias , ASTERACEAE : Anthemis , Aster , Cirsium , Croptilon , Helenium , Erigeron , Rudbeckia , Senecio , Solidago , Taraxacum , Vernonia , BRASSI- CACEAE: Barbarea , Brassica , Lepidium , Raphanus , Rorippa , CAPRIFOLIACEAE : Viburnum , CARYO- PHYLLACEAE: Gypsophila , CLUSIACEAE : Hypericum , ERICACEAE : Leucothoe , Vaccinium , FABACEAE : Baptisia , Lotus , Medicago sativa , Melilotus officinalis , Phaseolus , Robinia , Trifolium pratense , Vicia , HYDRANGEACEAE : Hydrangea , IRIDACEAE : Gladiolus , LAMIACEAE : Nepeta , Pycnanthemum , Salvia , PAEONIACEAE : Paeonia , PLANTAGINACEAE : Plantago , POLYGONACEAE : Fagopyrum , Polygonum , PORTULACACEAE : Claytonia , RHAMNACEAE : Ceanothus , ROSACEAE : Fragaria , Malus , Potentilla , Prunus , Pyracantha , Rosa , Rubus , Spiraea , SALICACEAE : Salix , SYMPLOCACEAE : Symplocos .

Comments. Common.

The holotypes of H. admirandus and D. perspicuus differ only in size and colour. The former is smaller and blue and the latter is green. These characters frequently vary within species of Dialictus and are a poor basis for recognising distinct species. Both colour forms have been collected at the same locality. DNA barcodes between specimens of each form do not differ.

The taxonomic limits of this species have not been well understood previously. Lasioglossum admirandum has been widely misapplied and has often been used for L. mitchelli , a similar but clearly distinct species. Morphologically it is very similar to a complex of several related species, herein referred to as the “ L. viridatum species-group” and defined as follows.

Figures

FIGURE 63. Lasioglossum admirandum (Sandhouse). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) mesoscutum. Scale bars, A–C = 1 mm.

FIGURE 64. Lasioglossum admirandum (Sandhouse). Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) mesoscutum; (E) ventral surface of genital capsule; (F) dorsal surface of gential capsule; (G) S7, S8. Scale bars, A–C = 1 mm, G = 0.5 mm.

FIGURE 65. Distribution of Lasioglossum admirandum (dark grey) and L. albipenne (light grey).