Lasioglossum (Hemihalictus) lustrans (Cockerell 1897)

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 : 12-20

Lasioglossum (Hemihalictus) lustrans (Cockerell 1897)

( Figs. 4E , 5E , 6E , 7E , 8E , 9 , 10 , 82A , 84B )

Panurgus lustrans Cockerell 1897a, p. 288 ♀

Syntypes. ♀ USA, New Mexico, Lincoln Co., Lone Mountain , near Silver Springs “ Mr. Clark Rodger’s ranch”, 7.vii.1896 on Pyrrhopappus [ CAS]

Hemihalictus lustrans (in Cockerell 1897 c, 1898; Mitchell 1960 ♂; Daly 1961, larva; Hurd 1979: catalogue; Moure & Hurd 1987: catalogue)

Lasioglossum (Hemihalictus) lustrans (in Michener 1947: description ♂, 1951: catalogue, 2007; Krombein 1967: catalogue)

Diagnosis. Both sexes of Lasioglossum lustrans can usually be recognised by the absence of vein 1rs-m, resulting in only two submarginal cells ( Fig. 1B ). A small proportion of individuals have vein 1rs-m present in both wings. Females of L. lustrans can also be recognised by the combination of mesosoma finely sculptured; pronotum rounded dorsolaterally; inner metatibial spur denticulate, teeth shorter than width of rachis ( Fig 5E ); and T1 anterior surface with appressed and erect hairs intermixed ( Fig. 82A ). Lasioglossum fedorense and L. swenki are similar, but both have pectinate inner metatibial spurs ( Figs. 5B, 5J ), three submarginal cells ( Fig. 1A ), and pronotum sharply angled dorsolaterally.

Males of L. lustrans can be recognised by the combination of clypeus black ( Fig. 6E ); mandible elongate, extending to opposing mandible base ( Fig. 6E ); antennal flagellomeres short, length approximately equal to width, except F11 longer than wide; F2 shorter than or subequal to F1; and pronotum with dorsolateral carina anterior to oblique sulcus.

Redescription. FEMALE. Length 5.9–6.9 mm. Head length 1.82–2.03 mm. Head width 1.85–2.08 mm. Wing length 4.5–5.3 mm. (n=5)

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

Structure. Head wide (L/W ratio = 0.92–0.99). Clypeus 3/4 below suborbital line. Eyes convergent below (UOD:LOD = 1.17–1.21). Gena width subequal to eye. Ocelli normal. Pronotal ridge smoothly rounded. Vein 1rsm usually absent. Protibial spur with apical serrations subequal in length to width of malus. Inner metatibial spur serrate, teeth 6–7, basal teeth shorter than width of rachis. Metapostnotum posterior margin angled onto posterior propodeal surface. Propodeal lateral carina not reaching dorsal margin, oblique carina absent or very obscure.

Surface sculpture. Supraclypeal area imbricate; punctures fine, shallow, dense (i=1–1.5d). Frons finely reticulate. Gena lineolate, postgena imbricate. Mesoscutum weakly imbricate, punctures fine, dense laterally (i=1– 1.5d), well-separated between parapsidal lines (i=1–4d). Mesepisternum relatively smooth, polished, punctate. Metapostnotum carinulate-rugulose, apical margin imbricate. Propodeum rugulose-imbricate. Metasomal terga polished, apical impressed areas weakly coriarious; punctures dense throughout, except T1 apical impressed area impunctate.

Pubescence. Head and mesosoma with sparse plumose hairs. Metafemoral scopa with dense plumose hairs. Propodeum with erect plumose and simple hairs. Metasomal terga with moderately dense apical fimbriae, continuous on T3–T4. T1 with intermixed appressed and erect hairs. Metasomal sterna with densely plumose scopa.

MALE. Length 5.0– 5.9 mm. Head length 1.35–1.50 mm. Head width 1.40–1.55 mm. Wing length 4.5–5.0 mm. (n=3)

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

Structure. Head wide (L/W ratio = 0.93–0.97). Eyes weakly convergent below (UOD:LOD = 1.02–1.20). Mandible long, reaching beyond opposing clypeal angle. Flagellomeres short, F2 subequal to F1, much shorter than scape. Gena width subequal to eye. Pronotal ridge rounded above, sharply angled anterior to sulcus, acute angle visible when viewed dorsally. Propodeal lateral carina nearly reaching dorsal margin.

Surface sculpture. Supraclypeal area imbricate; punctures fine, shallow, dense (i=1–1.5d). Ocellocular area polished, distinctly punctate. Gena and postgena weakly lineolate. Mesoscutum polished, weakly imbricate in part; punctures fine, dense laterally (i=1–1.5d), clearly separated between parapsidal lines (i=1–4d). Mesepisternum smooth, weakly lineolate transversely; punctures fine, distinct below scrobe. Metapostnotum carinulate-rugulose. Propodeum weakly imbricate. Metasomal terga polished, apical impressed areas coriarious; punctures close throughout.

Pubescence. Head and mesosoma with sparse plumose hairs. Paraocular area without evident tomentum. Propodeum largely bare, with scattered plumose hairs. Metasomal terga with apical fimbriae sparse; T1 with sparse, subappressed, anterior fan. Metasomal sterna with sparse, plumose hairs (1.5–2 OD); apical margins with moderately dense fimbriae.

Terminalia . As shown in Figs. 7E , 8E . Gonostylus slender, with short setae. Retrorse lobe long, narrow.

Taxonomic notes. Lasioglossum lustrans belongs to the black group of L. (Dialictus) s. l. sometimes referred to as the “acarinate (or carinaless) Evylaeus ” ( Michener 1990; Danforth et al. 2003; Pesenko 2007a). The absence of vein 1rs-m is usually used as a diagnostic character not only for the species but also for the subgenus L. ( Hemihalictus ) ( Ebmer 2002; Michener 2007). Gibbs (2010b) reported a case of L. lustrans from Wisconsin with three submarginal cells, which suggests the absence of vein 1rs-m is insufficient for delineating generic boundaries in this case. Additional specimens of L. lustrans from Wisconsin and Michigan with three submarginal cells have since been examined (see below). The nested position of L. lustrans within the “carinaless Evylaeus ” clade ( Fig. 2 ) clearly indicates its close relationship to these bees.

Biology. Lasioglossum lustrans is an oligolectic species most often associated with Pyrrhopappus carolinianus (Walter) DC. ( Asteraceae : Cichoriae ) ( Michener 1947; Daly 1961). Lasioglossum lustrans is matinal, which coincides with the availability of resources from the plant ( Estes & Thorp 1975). The northern range of L. lustrans exceeds that of P. carolinianus ( Estes & Thorp 1975) , which clearly implies that the bee is capable of using other resources when necessary. Arduser (2010) and Grundel et al. (2011) report L. lustrans , near the northern extent of its range, foraging on Krigia biflora S.F. Blake and K. virginica (L.) Willd., which also belong to the tribe Cichoriae (Asteraceae) . Lasioglossum lustrans has also been collected from Pyrrhopappus pauciflorus (D. Don) DC. , Cichorium intybus L., Hieracium gronovii L. ( Asteraceae ), and Cucurbita (Cucurbitaceae) ( Michener 1947; Mitchell 1960; Moure & Hurd 1987; Grundel et al. 2011).

Daly (1961) excavated nests of L. lustrans from two sites in Louisiana. All eight nests were occupied by a single female. Each nest was in bare ground with a vertical, unbranched main tunnel reaching a depth up to 29 cm. Cells were built at a slight downward angle at the end of 1.5 cm long lateroids. No nests had more than four fresh cells, but some, presumably reused nests, had up to ten old cells.

DNA barcodes. Six individuals have been sequenced (maximum intraspecific p-distance: 0.7%). A minimum p-distance of 6.0% was found between L. lustrans and the other species included here. When compared against the seven species of L. ( Hemihalictus ) included herein, the following 9 fixed differences were found: 28(T), 45(C), 168(A), 183(T), 204(A), 240(T), 289(A), 333(T), and 564(T) (see Table 2). A single fixed substitution distinguishes L. lustrans from other all species included herein: position 318(T).

Range. Fig. 11 .

Material examined. 228 (181 females, 47 males). Deposited in AMNH, BBSL, CAS, CUIC, IRCW, MSUC, PCYU, and UCDC. Locations of specimens with three submarginal cells are marked with an asterisk .

CANADA. ONTARIO: Norfolk Co.: Turkey Point , N42°42.105’ W80°19.584’, 8 June 2009 (A. Taylor) [ PCYU] (first record for Canada) .

USA. ALABAMA: Mobile Co.: Theodore; ARKANSAS: Desha Co.: McGehee, 3 mi. N; Garland Co.: Hot Springs ; Hempstead Co.: Fulton; Hot Spring Co. : Malvern; Nevada Co.: Prescott; DELAWARE: Sussex Co.; FLORIDA: Alachua Co. : Gainesville, Austin Carey For.; GEORGIA: Bryan Co.: Richmond Hill S.P.; Fulton Co.: Thomasville; KANSAS: Cherokee Co.: Baxter Springs; Treece; KENTUCKY: Wayne Co.; LOUISIANA: Vernon Par.: Fort Polk; MICHIGAN: Allegan Co.: Fennville, 3.3 mi WNW; Clare Co.: Harrison; Clinton Co.: Bath; Delta Co. : Brampton; Dickinson Co.*; Kalkaska Co.; Kent Co.; Lake Co.; Osceola Co. ; Ottawa Co.: Agnew, 2 mi NNE; Port Sheldon, 3 mi SE; West Olive; MISSISSIPPI: Forrest Co.: Camp Shelby, nr. Hattiesburg; Hattiesburg; NORTH CAROLINA: Hoke Co.: Fort Bragg Mil. Res.; Southern Pines; Moore Co.: Carthage; Carthage, 2 mi. SW; Carthage, 4 mi. W, Mt. Carmel Rd.; Southern Pines, 10 mi. N; Richmond Co.; Wake Co.: Cary; OKLAHOMA: Caddo Co. : Red Rock Canyon; Craig Co.: Vinita; Marshall Co.: Lake Texoma, nr. Willis; Lake Texoma, 2 mi. E Willis; SOUTH CAROLINA: Dillon Co.: Dillon; Chesterfield Co.; TENNESSEE: Fayette Co.: Oakland; Hardeman Co.: Bolivar; Knox Co.: Knoxville; TEXAS: Austin Co.: S.F. Austin S.P., nr. Sealy; Camp Co.: Daingerfield; Coke Co.: Gainesville; Dallas Co.: Dallas; Donley Co.: Lake McClellan; Kaufman Co.: Terrell; Panola Co.: Carthage; Sabine Co.: Milam; Wharton Co.: Wharton; WISCONSIN: Jackson Co.; Marinette Co.: Dunbar barrens*; Monroe Co.*; Wood Co.

Figures

FIGURE 1. Forewings of female Lasioglossum with arrows indicating weak distal veins. (A) Individual with three submarginal cells. (B) Individual with two submarginal cells. Basal vein (b), pterostigma (pt). Numbers indicate submarginal cells. Modified from Gibbs (2010a).

FIGURE 2. Inferred phylogeny of the Hemihalictus series of Lasioglossum based on 1 mitochondrial and 3 nuclear genes partitioned by genome and codon position and analysed using a mixed evolutionary model and Bayesian methods (modified from Gibbs et al. 2012b). Species included in our revision are denoted with black branches in the tree. Colour-coded bars represent subgenera (see legend). From left to right each column represents a different proposed classification: Michener (2007), Ebmer (2002) and our revised cladistic classification. Since Michener and Ebmer do not discuss each species or taxon included in our phylogeny some subgenera are left blank. The columns do not necessarily represent the opinions of those authors, but are based on our understanding of standard usage, which largely follows their proposed classifications.

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 9. Lateral habitus of female Lasioglossum (Hemihalictus) lustrans (Cockerell). Scale bar = 1 mm.

FIGURE 10. Lateral habitus of male Lasioglossum (Hemihalictus) lustrans (Cockerell). Scale bar = 1 mm.

FIGURE 11. Distribution map of Lasioglossum (Hemihalictus) lustrans (Cockerell). Heat map indicates predicted suitable range based on maximum entropy niche-modelling. Black circles indicate actual geo-referenced specimen records.

FIGURE 82. Propodeum, metapostnotum and anterior surface of T1 of female Lasioglossum (Hemihalictus). (A) L. lustrans showing fine metapostnotal sculpture and subappressed hairs on T1. (B) L. foxii showing metapostnotal rugae not reaching posterior dorsal margin. (C) L. inconditum showing metapostnotal rugae reaching posterior dorsal margin.

FIGURE 84. Clypeus and mandible of male Lasioglossum (Hemihalictus). (A) L. sopinci showing large clypeal maculation and elongate mandible. (B) L. lustrans showing entirely black clypeus and elongate mandible. (C) L. inconditum showing narrow, distal, clypeal maculation and short mandible.