Lasioglossum (Sphecodogastra) oenotherae ( Stevens 1920 )

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 : 86-88

Lasioglossum (Sphecodogastra) oenotherae ( Stevens 1920)

( Figs. 43E , 44E , 45E , 46E , 62 , 63 , 74B , 83A , 85B )

Halictus (Evylaeus) oenotherae Stevens 1920, p. 37 (♀)

Holotype ♀ USA, Kansas, Blue Rapids, 20.vi.1919 on “ Megapterium missouriense ” [ NMNH: 12033]. Examined. Halictus ralenci Crawford 1932, p. 70 ♀ (syn. Mitchell 1960)

Holotype. ♀ USA, North Carolina, Raleigh , 29.v.1924 ( CS Brimley) [ AMNH]. Examined by JG 2011

(Labels read “Raleigh NC C S Brimley 29-V-24/Acc. 33827/ Halictus ralenci Type Cwfd [handwritten]”).

Evylaeus oenotherae (in Knerer & Atwood 1964 ♂; Hurd 1979: catalogue; Moure & Hurd 1987: catalogue)

Lasioglossum (Evylaeus) oenotherae (in Krombein 1967: catalogue)

Lasioglossum (Sphecodogastra) oenotherae (in Michener 1951: catalogue)

Sphecodogastra oenotherae (in Mitchell 1960 redescription key ♀, ♂ as Evylaeus truncatus ; McGinley 2003: redescription, key ♂)

Diagnosis. Female L. oenotherae can be recognised by the combination of metapostnotum coarsely rugose ( Fig. 83A ) and tibial scopa with single row of rake-like hairs ( Fig. 74B ).

Male L. oenotherae can be recognised by the combination of flagellomeres relatively short, without distinct sensillar patterns, metasomal sterna with elongate hairs ( Fig. 85B ), and S2–S4 with distinct appressed tomentum basally ( Fig. 85B ).

Description. See McGinley (2003: 40).

Taxonomic notes. Lasioglossum oenotherae is the most commonly collected Onagraceae specialist member of L. ( Sphecodogastra ) in eastern North America. Mitchell (1960) incorrectly associated the male of L. oenotherae with L. truncatum . The correct males of these two species were identified by Knerer and Atwood (1964). Mitchell (1960) suggested that Evylaeus pineolensis might be the male of L. oenotherae . This synonymy was formalized by Sheffield et al. (2003). One of us (JG) recently examined the holotype of E. pineolensis and found it to be a male of L. nigroviride , a relatively dark metallic L. (Dialictus) ( Gibbs 2011). The correct synonymy was not obvious because the holotype of E. pineolensis has been bleached to such an extent that the natural metallic colouration has been completely lost.

Biology. As the name suggests, L. oenotherae is oligolectic on species in the genus Oenothera (Onagraceae) ( McGinley 2003). Ontario populations of L. oenotherae are solitary, forming nests in soil with sessile, clustered cells ( Knerer & MacKay 1969). Brood sizes were 12 to 20 cells per nest. Nests are found in aggregations of up to 25 nests per square metre, with the first nests being founded in mid-June in Ontario.

Zayed and Packer (2007) studied the population genetics of this species and found significant genetic structure among populations. Southern populations were found to deviate from Hardy-Weinberg equilibrium. Interestingly, Zayed and Packer (2007) report collecting L. oenotherae regularly from gardens with Oenothera , but the bee was not found visiting unmanaged ‘natural’ Oenothera populations. Additional collections by one of us (BND) in upstate New York follow the same pattern.

DNA barcodes. Two individuals have been sequenced. The minimum interspecific p-distance separating L. oenotherae from L. lusorium is 5.8%. No intraspecific variation was observed. Seven unique nucleotide substitutions are present among black weak-veined Lasioglossum : positions 22(T), 267(C), 303(A), 372(C), 426(C), 477(C), and 489(C) (see Table 2).

Range. Fig. 64 .

Material examined. 115 (69 females, 46 males) Deposited in CNC, CUIC, EMEC, LACM, MSUC, NCSU, PCYU, and ROMent .

CANADA. ONTARIO: National Capital Reg.: Ottawa; Toronto Div.: Toronto; QUEBEC: Montérégie Reg.: Mt. Saint Hilaire; Outaouais Reg.: Aylmer. (Also recorded from New Brunswick and Nova Scotia; McGinley 2003; Moure & Hurd 1987).

USA. GEORGIA: Rabun Co.: Rabun Bald ; KANSAS: Marshall Co.: Blue Rapids ; MASSACHUSETTS: Worcester Co.: Petersham ; MARYLAND: Prince George’s Co.: Greenbelt ; NEW YORK: Sullivan Co.: Beaver Kill; Tompkins Co. : Ithaca ; NORTH CAROLINA: Avery Co.: Grandfather Mt.; Harnett Co. : 10 mi S Lillington; Haywood Co. ; Jackson Co. : Locust Gap, Blue Ridge Pkwy.; Rich Mt. ; Macon Co. : Highlands ; Wayah Bald ; Wake Co .: Raleigh ; Yancey Co. : Mt. Mitchell ; VIRGINIA: Fairfax Co.: Springfield .

Figures

FIGURE 43. Faces of female Lasioglossum subgenera Evylaeus (A) and Sphecodogastra (B-I) in frontal view. (A) L. cinctipes. (B) L. boreale. (C) L. comagenense. (D) L. lusorium. (E) L. oenotherae. (F) L. quebecense. (G) L. seillean. (H) L. texanum (I) L. truncatum. Scale bar = 1 mm.

FIGURE 44. Faces of male Lasioglossum subgenus Evylaeus (A) and Sphecodogastra (B-I) in frontal view. (A) L. cinctipes. (B) L. boreale. (C) L. comagenense. (D) L. lusorium. (E) L. oenotherae. (F) L. quebecense. (G) L. seillean. (H) L. texanum (I) L. truncatum. Scale bar = 1 mm.

FIGURE 45. Genital capsules of male Lasioglossum subgenera Evylaeus (A) and Sphecodogastra (B-I) in dorsal view. (A) L. cinctipes. (B) L. boreale. (C) L. comagenense. (D) L. lusorium. (E) L. oenotherae. (F) L. quebecense. (G) L. seillean. (H) L. texanum (I) L. truncatum. Scale bar = 1 mm.

FIGURE 46. Genital capsules of male Lasioglossum subgenus Evylaeus (A) and Sphecodogastra (B-I) in ventral view. (A) L. cinctipes. (B) L. boreale. (C) L. comagenense. (D) L. lusorium. (E) L. oenotherae. (F) L. quebecense. (G) L. seillean. (H) L. texanum (I) L. truncatum. Scale bar = 1 mm.

FIGURE 62. Lateral habitus of female Lasioglossum (Sphecodogastra) oenotherae (Stevens). Scale bar = 1 mm.

FIGURE 63. Lateral habitus of male Lasioglossum (Sphecodogastra) oenotherae (Stevens). Scale bar = 1 mm.

FIGURE 64. Distribution map of Lasioglossum (Sphecodogastra) oenotherae (Stevens). Heat map indicates predicted suitable range based on maximum entropy niche-modelling. Black circles indicate actual geo-referenced specimen records.

FIGURE 74. Scopa of hind leg. (A) L. boreale—unmodified scopa. (B) L. oenotherae—modified scopa for Onagraceae pollen collection.

FIGURE 83. Propodeum and metapostnotum of female Lasioglossum (Sphecodogastra) in the Onagraceae specialist lusorium species-group. (A) L. oenotherae showing coarse sculpture and strong carinae. (B) L. lusorium showing fine sculpture and weak carinae.

FIGURE 85. Metasomal sterna of male Lasioglossum (Spheocodagastra) with arrows indicating pubescence and S6 medial area. (A) L. boreale showing short, sparse hairs and normal S6. (B) L. oenotherae showing long, dense hairs and concave S6.