Lasioglossum (Hemihalictus) birkmanni (Crawford 1906)

Gibbs, Jason, Packer, Laurence, Dumesh, Sheila & Danforth, Bryan N., 2013, Revision and reclassification of <i> Lasioglossum </ i> (<i> Evylaeus </ i>), <i> L. </ i> (<i> Hemihalictus </ i>) and <i> L. </ i> (<i> Sphecodogastra </ i>) in eastern North America (Hymenoptera: Apoidea: Halictidae), Zootaxa 3672 (1), pp. 1-116 : 20-23

Lasioglossum (Hemihalictus) birkmanni (Crawford 1906)

( Figures 4A , 5A , 6A , 7A , 8A , 12 , 13 )

Halictus birkmanni Crawford 1906a, p. 5 (♀)

Syntype. ♀ USA, Texas, Fedor , 24.iii.1902 (G. Birkmann) [ NMNH: 12038]. Examined by JG 2012 .

(Label reads “Fedor Texas [handwritten]/III 24 02 [handwritten]/G. Birkmann coll. [handwritten]/Type No. 12038 U.S. N.M. [numbers handwritten on red label]/ Halictus birkmanni ♀ Paratype Cwfd [handwritten on orange label]/ Evylaeus birkmanni (Crawf.) [handwritten]”)

Evylaeus birkmanni (in Hurd 1979: catalogue; Moure & Hurd 1987: catalogue)

Evylaeus macoupinensis (in Mitchell 1960 redescription, key ♂, misdet.; Hurd 1979: catalogue, misdet.; Moure & Hurd 1987: catalogue, misdet.)

Halictus (Evylaeus) quadrimaculatus (in Viereck 1916: catalogue)

Lasioglossum (Evylaeus) birkmanni (in Michener 1951: catalogue)

Lasioglossum (Evylaeus) macoupinense (in Michener 1951: catalogue; Krombein 1967: catalogue, misdet.)

Diagnosis. Both sexes of L. birkmanni can be recognised by the combination of head short (L/W ratio = 0.94–1.00) ( Figs. 4A , 6A ); pronotum smoothly rounded dorsolaterally; and mesepisternum distinctly punctate (as in Fig. 76B ). Lasioglossum birkmanni can be easily distinguished from most species, except L. macoupinense . Both sexes of L. macoupinense have head longer (L/W ratio = 1.02–1.09) ( Figs. 4F , 6F ). Female L. macoupinense have sparser punctation on the supraclypeal area (i=1–2.5d) than do L. birkmanni (i=1–1.5d). Male L. macoupinense have longer setae on the gonostylus ( Fig. 7F ).

Redescription. FEMALE. Length 4.8–6.3 mm. Head length 1.27–1.55 mm. Head width 1.35–1.65 mm. Wing length 3.9–4.8 mm. (n=5)

Colour. Head and mesosoma black. Antenna black, except ventral surface of flagellum reddish brown. Tegula pale yellow-testaceous. Legs dark brown, except medio- and distitarsi reddish brown. Wing membrane hyaline, faintly dusky. Pterostigma brown. Metasomal terga black-brown, apical margins pale brown.

Structure. Head wide (L/W ratio = 0.94–0.97). Clypeus 2/3 below suborbital line. Eyes strongly convergent below (UOD:LOD = 1.28–1.42). Gena narrower than eye. Ocelli normal. Pronotum smoothly rounded. Protibial spur with apical serrations shorter than width of malus. Inner metatibial spur pectinate, teeth 4–5, basal teeth longer than width of rachis. Propodeal lateral carina not reaching dorsal margin, oblique carina low, obscure.

Surface sculpture. Supraclypeal area imbricate, punctures dense (i≤d). Gena and postgena lineolate. Mesoscutum polished; punctures dense laterally (i≤d), distinctly separated between parapsidal lines (i=1–2d). Mesepisternum smooth, polished, distinctly punctate. Metapostnotum carinate-rugose basally, apical margin weakly imbricate. Propodeum imbricate-tessellate. Metasomal terga polished, apical impressed areas weakly coriarious; punctures dense, obscure posteromedially.

Pubescence. Head and mesosoma with sparse plumose hairs. Metafemoral scopa with dense plumose hairs. Propodeum with sparse plumose hairs. Metasomal terga with sparse apical fimbriae. T1 with sparse, erect plumose hairs. T2–T3 with basolateral patches of dense tomentum. Metasomal sterna with plumose scopa.

MALE. Length 4.2–5.5 mm. Head length 1.20–1.43 mm. Head width 1.24–1.48 mm. Wing length 3.3–4.1 mm. (n=6)

Colour. Head and mesosoma black. Clypeus apical half yellow. Mandible brown basally, yellow apically. Labrum yellow. Antenna black, except ventral surface of flagellum brown. Legs dark brown, except tarsi, bases and apices of pro- and mesotibiae yellow, protibia largely yellow-testaceous. Tegula pale yellow. Wing membrane hyaline. Pterostigma pale brown. Metasomal terga dark brown.

Structure. Head wide (L/W ratio = 0.95–1.00). Mandible short, reaching opposing clypeal angle. Flagellomeres, except F1, moderately elongate, F2 shorter than F1 and pedicel combined, much shorter than scape. Eyes convergent below (UOD:LOD = 1.53–1.64). Gena narrower than eye. Pronotum smoothly rounded. Propodeal lateral carina nearly reaching dorsolateral slope.

Surface sculpture. Supraclypeal area weakly imbricate; punctures dense, shallow (i≤d). Gena and postgena lineolate. Mesoscutum polished; punctures fine, dense laterally (i≤d), well-separated between parapsidal lines (i=1–2d). Mesepisternum polished, distinctly punctate. Metapostnotum on basal half carinate-rugose, apical margin imbricate. Propodeum lateral surface weakly rugulose-imbricate, posterior surface weakly imbricate. Metasomal terga polished; punctures deep, close basally. T2–T6 apical impressed areas with sparse, scattered punctures.

Pubescence. Head and mesosoma with sparse plumose hairs. Paraocular area below eye emargination with relatively sparse tomentum. Propodeum largely bare, with scattered plumose hairs. Metasomal terga nearly bare, apical fimbriae extremely sparse. Metasomal sterna with sparse, plumose hairs (1.5–2 OD).

Terminalia . As shown in Figs. 7A , 8A . Gonostylus small, with short setae. Retrorse lobe long, narrow, attenuated apically.

Taxonomic notes. The original description of L. birkmanni highlights the extensive yellow (“testaceous”) colouration on the legs ( Crawford 1906a). Until recently, L. birkmanni was only recognised from Texas ( Moure & Hurd 1987). Individuals with brown legs occur east of the Mississippi River, but the brown form has traditionally been referred to by the epithet macoupinense . Due to an unfortunate lectotype designation ( Cresson 1928; see below) this name has not been correctly applied by most authors ( Mitchell 1960; Knerer & Atwood 1964). Specimens of the yellow colour form have now been examined from as far east as Florida and north to Michigan. There is evidence of gradation between the two colour forms and specimens of both forms have been examined from the same locality. In one case, specimens collected at a nest site in clay banks of a ravine in southern Alabama (M. Deyrup, in litt.) showed variation from completely brown, partially yellow to completely yellow legs. Colour variation in halictine bees has been reported previously (e. g. Batra 1966; McGinley 1986; Miyanaga et al. 1999; see also below), making it an unreliable basis for delimiting species. DNA barcodes from both colour forms are consistent with them representing variants of a single species.

Crawford (1906a) did not designate a holotype for Halictus birkmanni , nor did he indicate how many specimens were in the type series. The number of specimens is given for other species described in the same paper, so it is plausible that the description was based on a single specimen. The specimen above is the only one known to us, but it has a paratype label attached written in what appears to be Crawford’s handwriting. The specimen is missing the metasoma and the head and pronotum are detached and glued to a label. We defer designating this specimen as a lectotype given its poor condition and the possibility of additional type specimens suggested by the paratype label.

Biology. This species is a polylectic ( Moure & Hurd 1987) ground-nester (M. Deyrup, in litt.). There are no published accounts of social level, but it is expected to be solitary based on its close relationship to other solitary species ( Danforth et al. 2003; Gibbs et al. 2012b).

DNA barcodes. Nine specimens, including both colour forms, were sequenced (four samples with 6–14 uncertain base calls) (maximum intraspecific p-distance: 2.6%; 0.7% when discounting poor sequences). Divergent sequences do not represent differences between colour forms. Lasioglossum birkmanni differs from L. macoupinense by 21 fixed substitutions: 15(T), 30(C), 66(T), 129(T), 132(T), 216(T), 219(C), 270(C), 276(A), 315(T), 339(C), 354(A), 363(C), 378(A), 420(T), 423(A), 460(T), 552(C), 558(A), 639(T), and 642(C) (see Table 2). The minimum interspecific p-distance separating L. birkmanni from L. macoupinense is 3.9%. No unique fixed substitutions distinguish L. birkmanni from all other eastern Lasioglossum combined.

Range. Fig. 14 .

Material examined. 377 (301 females, 76 males). Deposited in ABS, AMNH, ANSP, BBSL, CAS, CMNH, CNC, CTMI, CUIC, IRCW, MCPM, MCZ, MSUC, NMNH, PCYU, PMNH, ROMent, and UCRC. Localities with extensively yellow-legged individuals are marked with an asterisk .

CANADA. ONTARIO: Essex Co.: Point Pelee; Kent Co.: Rondeau Pk.; Niagara Reg.: Niagara Falls ; Niagara Glen; Peel Reg.: Mississauga; Toronto Dist. : Toronto ; QUEBEC: Outaouais Reg.: Norway Bay .

USA. ALABAMA: DeKalb Co.: DeSoto S.P; Monroe Co.: Beaver Creek; Randolph Co.: Wadley*; CONNECTICUT: Hartford Co.: E. Hartford; New London Co.: Waterford; DISTRICT OF COLUMBIA: Washington; FLORIDA: Alachua Co. : Gainesville*; Desoto Co.: Arcadia; Leon Co.: Apalachicola N.F. *; Sarasota Co. : Oscar Scherer SRA*; Volusia Co. : Daytona; GEORGIA: Fulton Co.: Atlanta; Rabun Co.: Holcomb Creek*; Rabun Bald; Satolah; ILLINOIS: Jackson Co.: Midland Hills; Macoupin Co.: Carlinville; Union Co.: Giant City S.P.; Pine Hills; INDIANA: Parke Co.: Marshall; KANSAS: Douglas Co.: Baldwin, 2 mi. N; Jefferson Co.: Perry; LOUISANA: St. Tammany Par.: Abita Creek Preserve*; MARYLAND: Anne Arundel Co.; Montgomery Co.; Prince George’s Co.; MASSACHUSETTS: Dukes Co.: Martha’s Vineyard; Hampden Co.: Mt. Tom State Res.; Hampshire Co.: Amherst; Granby; Middlesex Co.: Bedford; Holliston; Waltham; Norfolk Co.: Milton; Worcester Co.: Petersham; MICHIGAN: Allegan Co.: Fennville; Berrien Co.: Sodus; Ingham Co.: Holt, 2 mi. SW; Jackson Co.: MacCready Res.*; Kalamazoo Co.: Gull Lake Biol. Sta.; Muskegon Co.; MISSOURI: Barry Co.: Roaring River S.P.; Montgomery Co.: Graham Cave S.P.; St. Louis Co.: Tyson Res. Sta., nr. Eureka; NEBRASKA: Douglas Co.: Omaha, Fontenelle For.; NEW YORK: Cayuga Co. : Fair Haven Beach S.P.; Spring Lake; Greene Co.; Otsego Co.: East Worcester; Saratoga Co.; Schuyler Co.: Texas Hollow, nr. Bennettsburg; Suffolk Co.: E. Islip; Sullivan Co.: Roscoe; Tompkins Co.: Slaterville Wildflower Pres.; Ithaca; Coy Glen, Ithaca; Robert H. Treman S.P., Ithaca; Six-Mile Creek, Ithaca; Van Natta’s Dam, Ithaca; Michigan Hollow, W of Danby; Taughannock Falls S.P.; Trumansburg; NORTH CAROLINA: Blake Co.: White Lake ; Buncombe Co.: Black Mt.; Pisgah N.F., 5 mi. ESE Barnardsville; Carter Co.: Davis; Cumberland Co.: Fort Bragg; Durham Co.: Duke For. Nat. Area; Graham Co.: Cherokee; Robbinsville; Jackson Co.: Whiteside Mt., Highlands*; Macon Co.: Franklin; Franklin, 10 mi. W; Wayah Bald; Wayah Bald, base; Highlands; Pender Co.: Sampson Co.: Ivanhoe; Wake Co.: Raleigh; Umstead S.P.; OHIO: Franklin Co.: Columbus; Hocking Co.; OKLAHOMA: Pawnee Co.: Pawhuska; PENNSYLVANIA: Allegheny Co.: Pittsburgh; Erie Co.: Avonia; SOUTH CAROLINA: Oconee Co.: Mountain Rest; Richland Co.: Columbia*; TENNESSEE: Sevier Co.: Twin Creeks; TEXAS: Bastrop Co.: Stengl Biol. Sta., Smithville*; Lamar Co.: Camp Maxey*; Travis Co.: Austin*; VIRGINIA: Falls Church*; Virginia Beach*; Albemarle Co.; Arlington Co.: Arlington; Augusta Co. : slopes of Elliot Knob*; Fairfax Co.: Dunn Loring; Scott’s Run; Springfield; Westmoreland Co.: Westmoreland S.P.; WEST VIRGINIA: Hampshire Co.; Hardy Co.: Lost River S.P.; Randolph Co.: Cheat Mt.; WISCONSIN: Grant Co.: Rutledge; Wyalusing.

Figures

FIGURE 4. Faces of female Lasioglossum subgenus Hemihalictus in frontal view. (A) L. birkmanni. (B) L. fedorense. (C) L. foxii. (D) L. inconditum. (E) L. lustrans. (F) L. macoupinense. (G) L. nelumbonis. (H) L. pectinatum. (I) L. pectorale. (J) L. sopinci. (K) L. swenki. Scale bar = 1 mm.

FIGURE 5. Drawings of inner metatibial spurs of female Lasioglossum subgenera Hemihalictus (A-K), Evylaeus (L), and Sphecodogastra (M-Q). (A) L. birkmanni. (B) L. fedorense. (C) L. foxii. (D) L. inconditum. (E) L. lustrans. (F) L. macoupinense. (G) L. nelumbonis. (H) L. pectinatum. (I) L. pectorale. (J) L. sopinci. (K) L. swenki. (L) L. cinctipes. (M) L. boreale. (N) L. comagenense. (O) L. quebecense. (P) L. seillean. (Q) L. truncatum. See McGinley (2003) figures 61, 62, and 65 for images of inner metatibial spurs of L. lusorium, L. oenotherae, and L. texanum.

FIGURE 6. Faces of male Lasioglossum subgenus Hemihalictus in frontal view. (A) L. birkmanni. (B) L. fedorense. (C) L. foxii. (D) L. inconditum. (E) L. lustrans. (F) L. macoupinense. (G) L. nelumbonis. (H) L. pectinatum. (I) L. pectorale. (J) L. sopinci. (K) L. swenki. Scale bar = 1 mm.

FIGURE 7. Genital capsule of male Lasioglossum subgenus Hemihalictus in dorsal view. (A) L. birkmanni. (B) L. fedorense. (C) L. foxii. (D) L. inconditum. (E) L. lustrans. (F) L. macoupinense. (G) L. nelumbonis. (H) L. pectinatum. (I) L. pectorale. (J) L. sopinci. (K) L. swenki. Scale bar = 1 mm.

FIGURE 8. Genital capsule of male Lasioglossum subgenus Hemihalictus in ventral view. (A) L. birkmanni. (B) L. fedorense. (C) L. foxii. (D) L. inconditum. (E) L. lustrans. (F) L. macoupinense. (G) L. nelumbonis. (H) L. pectinatum. (I) L. pectorale. (J) L. sopinci. (K) L. swenki. Scale bar = 1 mm.

FIGURE 12. Lateral habitus of female Lasioglossum (Hemihalictus) birkmanni (Crawford). Scale bar = 1 mm.

FIGURE 13. Lateral habitus of male Lasioglossum (Hemihalictus) birkmanni (Crawford). Scale bar = 1 mm.

FIGURE 14. Distribution map of Lasioglossum (Hemihalictus) birkmanni (Crawford). Heat map indicates predicted suitable range based on maximum entropy niche-modelling. Black circles indicate actual geo-referenced specimen records.

FIGURE 76. Mesepisternum of female Lasioglossum. (A) L. inconditum showing weak, rugulose sculpture. (B) L. pectinatum showing punctation. (C) L. pectorale showing coarse, rugose sculpture throughout. (D) L. comagenense showing weak, rugulose sculpture. (E) L. lusorium showing appressed pubescense. (F) L. truncatum showing rugose sculpture becoming rugulose anterior to mesocoxa.