Lasioglossum (Dialictus) reticulatum (Robertson)

Gibbs, Jason, 2011, Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini), Zootaxa 3073, pp. 1-216 : 163-167

Lasioglossum (Dialictus) reticulatum (Robertson)

( Figures 175–179 )

Halictus fulvipes Smith, 1853: 67 . Ƥ. (junior primary homonym of Halictus fulvipes Klug , in Germar, 1817) Holotype. Ƥ USA, Florida (East), St. John’s Bluff; [BMNH]. Examined.

Halictus reticulatus Robertson, 1892: 268 . Ƥ.

Lectotype. Ƥ USA, Florida, Citrus Co., Inverness, 12.ii.1891 (C. Robertson) [INHS: 9987] by W. E. LaBerge (in Webb 1980). Examined.

Halictus rhododactylus Dalla Torre, 1896: 80 (replacement name for H. fulvipes Smith ).

Taxonomy. Michener, 1951: Lasioglossum (Chloralictus) reticulatum , p. 1117 (catalogue); Mitchell, 1960: Dialictus reticulatus , p. 416 (redescription); Krombein, 1967: Lasioglossum (Dialictus) reticulatum , p. 465 (catalogue); Moure and Hurd, 1987: Dialictus reticulatus , p. 126 (catalogue).

Diagnosis. Female L. reticulatum can be distinguished from all other eastern USA Dialictus except L. bruneri by the widely divergent hypostomal carinae ( Fig. 10 C) and coarsely sculptured mesosoma ( Figs. 4 A, 176). Female L. reticulatum lack the distally produced hypostomal carina and anteriorly excavated protrochanter that are present in L. bruneri .

Male L. reticulatum can be recognised by the combination of mesoscutum rugose on anterior margin ( Fig. 178 ), mesepisternum coarsely rugose, and tibiae and femora and reddish brown ( Fig. 177 A). They are most similar L. bruneri , which have tibiae and femora dark brown.

Redescription. FEMALE. Length 6.23–6.66 mm; head length 1.63–1.92 mm; head width 1.74–2.02 mm; forewing

length 4.17–4.96 mm.

Colouration. Head and mesosoma bluish green. Labrum and mandible reddish brown. Antenna blackish brown, flagellum with ventral surface brown. Tegula reddish brown. Wing venation and pterostigma amber. Legs brown except tarsi, outer surface of protibia, apex and base of mesotibia, and metatibia reddish brown to amber. Metasoma blackish brown, terga and sterna with apical margins reddish brown.

Pubescence. Dull white to yellowish white. Moderately dense. Head and mesosoma with moderately dense woolly hairs (1–1.5 OD), longest on genal beard, metanotum, and mesopleuron (2–2.5 OD). Paraocular area with sparse subappressed hairs. Gena with sparse tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with sparse, fine hairs. T1 acarinarial fan with narrow dorsomedial opening above, nearly reaching upper margin of declivitous surface. T2–T3 basolateral areas obscured by dense tomentum. T4 disc largely obscured by dense tomentum and with sparse, fringes. T2 apicolateral and T3–T4 apical margins with sparse apical fringes.

Surface sculpture. Face weakly imbricate, punctation strong. Clypeal punctation moderately dense (i=1–2d). Supraclypeal area and lower paraocular are punctation dense (i<d). Antennocular area rugose. Upper paraocular area and frons punctate-reticulate. Ocellocular area punctation irregular (i≤d). Gena and postgena coarsely carinulate. Mesoscutum imbricate, punctation very strong, distinctly separated medially (i≤d), rugoso-reticulate laterad of parapsidal line and anterolaterally. Mesoscutellum weakly imbricate, submedial punctation moderately sparse (i=1–3d). Axilla reticulate. Metanotum rugose. Preëpisternum and mesepisternum coarsely rugose, lower mesepisternum polished, carinulate-punctate. Metepisternum with upper half rugoso-carinulate, lower half imbricate. Metapostnotum coarsely rugoso-carinulate, interstices polished and shining. Propodeum with dorsolateral slope coarsely rugose, lateral and posterior surfaces rugulose. Metasomal terga polished except apical margins coriarious, most evident on T3–T4, punctation fine and deep throughout (i=1–2d).

Structure. Head wide (length/width ratio = 0.93–0.94). Eyes convergent below (UOD/LOD ratio = 1.10–1.18). Clypeus 1/2 below suborbital line, apicolateral angles rounded. Antennal sockets close (IAD/OAD <0.5). Frontal line carinate, ending 2 OD below median ocellus. Gena nearly as wide as eye. Hypostomal area deeply excavated, carinae widely divergent towards mandible bases. Pronotum with dorsolateral angle obtuse. Inner metatibial spur pectinate with 3–4 branches. Metapostnotum delimited from remainder of dorsal surface weak carina. Metapostnotum relatively truncate (MMR ratio = 1.29–1.50), posterior margin carinate. Propodeum with oblique carina strong, lateral carina reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.81 mm; head length 1.66 mm; head width 1.70 mm; forewing length 4.17–4.36 mm.

Colouration. Head and mesosoma dull metallic blue with green reflections. Flagellum with ventral surface reddish brown. Tegula yellowish brown. Wing venation and pterostigma brownish yellow. Legs brown, except metafemora dorsally, tibiae, and tarsi brownish yellow to orange.

Pubescence. Face with tomentum obscuring lower paraocular area and partially obscuring clypeus, supraclypeal area, upper paraocular area and frons. Metasomal terga without tomentum. S3 with dense plumose hairs and S4–S5 with lateral plumose hairs.

Surface sculpture. Coarse throughout. Mesoscutellum reticulate. Metepisternum rugoso-carinulate. Metasomal terga with apical impressed margins virtually impunctate.

Structure. Head moderately wide (length/width ratio = 0.97). Eyes strongly convergent below (UOD/LOD ratio = 1.40). Clypeus 2/3 below suborbital line, apicolateral margins subparallel. Antennal sockets distant (IAD/OAD <1.3). Frontal line carinate, ending <2 OD below median ocellus. Hypostomal carinae only slightly divergent towards mandibles. Pedicel shorter than F1. F2 length 1.8X F1. F2–F10 moderately elongate (length/width ratio = 1.38–1.83). Metapostnotum moderately elongate (MMR ratio = 1.21), posterior margin sharply angled onto posterior surface.

Terminalia . S7 with median lobe narrowly clavate, sides concave, apex rounded ( Fig. 179 ). S8 with apicomedial margin weakly convex ( Fig. 179 ). Genital capsule as in Fig. 179 . Gonobase with ventral arms narrowly separated. Volsella roughly ovoid. Gonostylus narrow and elongate, dorsal setae elongate. Retrorse lobe elongate, attenuated apically.

Range. South-eastern USA ( Fig. 174 ). USA: AL, FL, GA, NC, SC, TX.

Additional material examined. USA: ALABAMA: 1Ƥ Baldwin Co., Bon Secour N.W. Ref., T9S R2E Sec. 25 N, 13.x.1991 (G.C. Eickwort); 1Ƥ Baldwin Co., Bon Secour N.W. Ref., T9S R2E Sec. 23 E, 24 W, 12–16.x.1991 (T. Scheifer); FLORIDA: 1Ƥ Bay Co., St. Andrews S.P., 17.iv.1964 (G.C. Eickwort); 13 Lake Co., Leesburg, 8.v.1961 (C.H. Curran); 1Ƥ Levy Co., 13.ix.1955 (R.A. Morse); 1Ƥ Marion Co., Ocala N.F., 30 mi E Ocala, 30.iii.1974 (G.C. Eickwort); [ CUIC]; 1Ƥ Alachua Co., Gainesville, 18–25.vi.1987 (D.B. Wahl); [ CNC]; 1Ƥ13 Inverness (C. Robertson); [ INHS]; 1Ƥ Duval Co., 2.iv.1959 (T.B. Mitchell); [ NCSU]; 233 Sarasota Co., MCC – Venice Campus, 24.iii.1997 (K.J. Maharay, S.M. Fullerton); 26ƤƤ Seminole Co., Lower Wekiva River St. Pres., 22.vii.2001 (P. Russell, S. Fullerton); 50ƤƤ Seminole Co., Lower Wekiva River St. Pres., 2.xii.2001 (P. Russell, S. Fullerton); [ UCFC]; GEORGIA: 72 ƤƤ Liberty Co., St. Catherines Isl., N31°41ʹ W81°0 9ʹ, 31.iv–04.v.1995 (A. Sharkov); 12 ƤƤ Liberty Co., St. Catherines Isl., N31°40.3ʹ W81°0 9.5ʹ, 23-28.vi.1996 (A. Sharkov); 24 ƤƤ Liberty Co., St. Catherines Isl., Road b/w Windmill 2nd and Gator Pond, 22–27.vi.1995 (A. Sharkov); [ PCYU]; 1Ƥ McIntosh Co., Sapelo Isl, 28.iv–9.v.1987 ( BRC Hym Team); [ CNC]; NORTH CAROLINA: 1Ƥ Carolina beach, 20.iv.1930; [ CUIC]; TEXAS: 1Ƥ Nacogdoches Co., N31.5011 W094.7839, 2–18.vi.2010 (C. Adams); [ CUIC]; SOUTH CAROLINA: 7ƤƤ Dorchester Co., Francis Beidler For., 10 km NE Harleyville, bald cypress swamp, 11–23.vi.1987; 28ƤƤ 333 Hilton Head Is., 11–23.vii.1965 (H.F. Howden); [ CNC].

Floral records. ANACARDIACEAE : Rhus ; ASTERACEAE : Bidens , Solidago ; CAPRIFOLIACEAE : Lonicera dioica ; ERICACEAE : Vaccinium ; FABACEAE : Melilotus ; ROSACEAE : Crataegus , Photinia , Prunus , Rubus ; SMILA- CACEAE: Smilax ecirrhata , S. herbacea , S. tamnoides .

DNA Barcode. Available.

Comments. Common.

Some specimens of L. bruneri particularly in the Midwest lack strongly produced hypostomal carinae. These have sometimes been mistaken for L. reticulatum as a result.

Figures

FIGURE 4. Mesoscutum of female Lasioglossum (Dialictus) showing sculpture and punctation variation. (A) L. reticulatum, (B) L. cressonii, (C), L. nymphaearum, (D). L. (D.) sp., (E) L. heterognathum, (F) L. coreopsis, (G) L. pilosum, (H) L. nigroviride, (I) L. lineatulum.

FIGURE 10. Hypostomal carina variation in female Lasioglossum (Dialictus). (A) subparallel (L. connexum); (B) divergent (L. heterognathum); (C) divergent (L. reticulatum).

FIGURE 174. Distribution map of Lasioglossum raleighense (stars) and L. reticulatum (circles).

FIGURE 175. Lasioglossum reticulatum (Robertson) female, (A) lateral habitus, (B) face. Scale bars = 1 mm.

FIGURE 176. Lasioglossum reticulatum (Robertson) female, dorsal view of mesosoma.

FIGURE 177. Lasioglossum reticulatum (Robertson) male, (A) lateral habitus, (B) face. Scale bars = 1 mm.

FIGURE 178. Lasioglossum reticulatum (Robertson) male, dorsal view of mesosoma.

FIGURE 179. Lasioglossum reticulatum (Robertson) male terminalia, (A) ventral view, (B) dorsal view. Scale bar = 0.5 mm.