﻿Habralictus and Lasioglossum of Saint Lucia and Saint Vincent and the Grenadines, Lesser Antilles (Hymenoptera, Apoidea, Halictidae)

﻿Abstract The new species and the first halictid bees documented from Saint Lucia Habralictusreinae, Lasioglossum (Dialictus) luciae, and L. (Habralictellus) delphiae are described. A fourth species, L. (D.) dominicense, is tentatively recorded from the island. The species are illustrated and compared to similar ones from the Lesser Antilles. Lasioglossum and Habralictus from neighbouring Saint Vincent and the Grenadines are reviewed and a key to Lasioglossum provided, including the description of another new species, L. (Dialictus) gemmeum. Trigonanigrocyanea Ashmead and Dufoureasubcyanea Ashmead are synonymised under Lasioglossumcyaneum (Ashmead). Notes on the obscure Lasioglossum (Dialictus) minutum (Fabricius) are provided. A new name, Lasioglossum (Homalictus) minuens, is provided for a secondary homonym Homalictusminutus Pauly. The potential for additional species richness in Saint Lucia and the Lesser Antilles is briefly discussed.

Etymology. This brilliant, shining bee is appropriately named for Reina Rybuck, a curious and inquisitive girl who loved insects. Her light shone bright but too briefly. She is remembered with love and affection by those who knew her.
Notes. Of the five Habralictus species known from the Lesser Antilles, all seem to be limited to higher elevations (272-762 m) on the islands (Ashmead 1900;Smith-Pardo 2009;Gibbs , 2016. Habralictus reinae was taken from protected canopy forests that are particularly wet. It is notable for future collection efforts that this species was predominantly collected from UV light traps, despite more frequent use of Malaise traps by collectors and daytime net collecting (M. Ivie, in litt.). Fig. 4 Augochlora claviventris (1900: 217). Saint Vincent -windward side. 1500 feet.
Females of L. luciae and L. kilpatrickae are very similar and definitive characters for distinguishing them are not currently known. The gena of L. luciae may be more distinctly lineolate (Fig. 5D) and T1 more distinctly coriarious (Fig. 5E), but too few specimens are available of each species to be sure these characters are consistent. Both L. luciae and L. kilpatrickae are easily distinguished from L. plumbeum and L. sanctivincenti by absence of punctation on the apical impressed areas of T2, occurring only obscurely on the lateral portions. In contrast, both L. plumbeum and L. sanctivincenti have distinct, albeit fine punctures across the apical impressed areas of T2.
The male of L. luciae differs from L. kilpatrickae by the less abundant tomentum of the face (Fig. 6C), which only weakly obscures the lower paraocular area, more evident microsculpture on the medial portion of the mesoscutum and anterior face of T1, and the relatively dense punctures on T1-T3, which end near the border of the apical impressed area, such that at least two thirds of the segments are densely punctate. Lasioglossum kilpatrickae has tomentum obscuring the lower paraocular area and proximal portion of the clypeus (Fig. 7B). The mesoscutum has microsculpture between punctures limited to the anterior portion and is largely polished on the anterior face of T1. Furthermore, the punctation of T1-T3 is weak distally such that nearly half the longitudinal length of the segment is sparsely punctate to impunctate. T1 has a nearly impunctate medial line. Description. Female (n = 2). Length 5 mm; head length 1.4 mm; head width 1.4 mm; intertegular distance 1.0 mm; wing length 1.7 mm.
Colouration. Head and mesosoma dull metallic blue-green. Clypeal apex dark brown, base yellow. Labrum reddish brown to orange. Mandible orange with black base and red apex. Flagellum dark brown, F2-F11 orange-brown ventrally. Pronotal lobe reddish brown. Tegula reddish brown. Wing membrane hyaline, veins with subcosta brown to dark brown, otherwise amber. Legs brown, except medio-and distitarsi and portions of metabasitarsus reddish brown. Metasoma blackish brown, apical impressed area reddish brown.
Etymology. The specific epithet is derived from the name of the island. Saint Lucia is the only sovereign nation named after a historical woman.
Notes. Males are associated with females in part by the shared head length consistent with patterns seen between L. dominicense and L. kilpatrickae in Dominica. Notes. We ascribe the Saint Lucia material to L. dominicense without supporting evidence to the contrary. Although there seems to be some pattern of distinct species across islands in the Lesser Antilles, we are unable to confidently differentiate females of L. dominicense from Saint Lucia and Dominica at this time. As a lowland species occurring near the beach, it is most consistent with a multi-island distribution. Additional comparative study including males, specimens from Martinique, and molecular data would be useful. Diagnosis. Lasioglossum delphiae is easily distinguishable as a member of the subgenus Habralictellus. It has two submarginal cells (1rs-m absent). It closely resembles L. (H.) roseauense from Dominica. Lasioglossum delphiae has the mesoscutellum very weakly sculptured, almost polished with distinct, sparse punctures (mesoscutellum dull, sculpturing stronger, similar to that of mesoscutum in L. roseauense) and the metasomal terga have orange bands basally (all dark in L. roseauense). There is more yellow on the foreleg of L. delphiae than L. roseauense, although such colour characters may not be reliable given the limited material available.
Etymology. The species is named for Casey Delphia for her kind support of JG's studies of Caribbean bees generally and in appreciation for collecting the specimens above and bringing them to his attention.
Notes. Lasioglossum delphiae was collected from dry forest/beach habitats near the coast (C. Delphia, in litt.).

Lasioglossum (Dialictus) cyaneum (Ashmead 1900) Figs 10-13
Halictus cyaneus Ashmead (1900: 218-220 Taxonomic notes. Lasioglossum cyaneum is structurally similar to L. plumbeum and L. sanctivincenti but is easily recognisable by the entirely blue body and dark wing venation. The male T1-T6 are blue on the disc and dark reddish brown on the lateral and apical margins. The head is distinctly shorter (female and male face length/head width = 0.82-0.85) than L. plumbeum (male face length/head width = 0.87-0.90). Both Dufourea subcyanea and Trigona nigrocyanea were described from single males in the same publication with Halictus cyaneus. The former differs from L. cyaneum only in the absence of vein 1rs-m, leading to two submarginal cells rather than three. Loss of this vein is relatively common in L. (Dialictus) (Gibbs 2010b;Scarpulla 2018; see also L. gemmeum below), which led to the synonymy of the genus-group names Dialictus and Chloralictus (Mitchell 1960). The holotype of Trigona nigrocyanea is glued to the side of a card and has most of the metasoma missing. It is very evidently a Lasioglossum (Dialictus). The first tergum is intact and shows distinct metallic reflections consistent with L. cyaneum. Ashmead (1900) describes the abdomen as 'rufous, black at base only', but cannot be verified with most of the metasoma missing. In other respects, the holotype matches well with L. cyaneum, including the relatively smooth metapostnotum between carinulae.

Lasioglossum (Dialictus) plumbeum (Ashmead 1900) Figs 14-16
Halictus plumbeus Ashmead (1900: 218, 220    Notes. Lasioglossum sanctivincenti is quite similar to L. plumbeum. The most striking difference is the darker blue colour of the head and mesosoma of L. plumbeum. Lasioglossum sanctivincenti has a shorter head (face length/head width ratio = 0.82 SD 0.02) than L. plumbeum (0.86 SD 0.01). Mesoscutal puncture density is subtly different between the two species. In L. sanctivincenti punctures laterad of the parapsidal line are dense, but distinctly separated. These are nearly reticulate in L. plumbeum, without clear interspaces. Immediately mesad of the parapsidal line, L. sanctivincenti has distinctly separated punctures (IS ≤ 1 PD), but these are denser in L. plumbeum (IS ≤ 0.5 PD). Ashmead's (1900) original measurements suggest that L. santivincenti is larger (4-5.5 mm) than L. plumbeum (3.5-4.5 mm). In Sandhouse's (1924) key, they separate at couplet 43 based on size and Cockerell (1938) also refers to the smaller size of L. plumbeum. However, this may be an artefact of H.H. Smith's original sample as more recently collected specimens of L. plumbeum include a large size range (> 5 mm) overlapping with that of L. sanctivincenti. The size variation in L. plumbeum may be an indication of weakly defined social castes in L. plumbeum, which is a common feature of eusocial halictines (Michener 1990).
Colouration. Head and mesosoma dull metallic blue-green to golden-green, except as follows. Labrum reddish brown. Mandible yellow-orange with brown base and red apex. Clypeal apex dark brown. Antenna dark brown, flagellum with ventral surface reddish brown. Pronotal lobe yellow-orange. Tegula amber. Wing membrane hyaline with dark setae, venation pale brown. Legs amber-brown. Metasomal terga orange.
Pubescence. Dull white. Relatively sparse erect setae throughout, without tomentum, except on gena near eye, pronotal dorsolateral angle and lobe. Metasomal T1 with fan virtually absent, no erect setae medially. T2 without apical fimbriae, T3-T4 with only sparse fine setae on apical impressed areas. Scopa well developed on hind leg and metasomal sterna.
Colouration. Head and mesosoma green to golden green. Clypeal apex reddish brown. Labrum reddish brown. Mandible brown, orange apically. Flagellum reddish brown, sometimes orange ventrally. Pronotal lobe reddish brown to orange. Tegula orange. Wing membrane hyaline, veins brown to dark brown. Legs reddish brown with femur-tibia joints, base and apex of tibiae, and tarsi orange. Metasoma reddish brown.
Etymology. The specific epithet is a Latin adjective in the nominal singular meaning glittering.
Taxonomic notes. The distribution and identity of L. minutum remains in doubt. Fabricius (1798) did not specify the number of specimens examined, but a single male type is known. Moure (1960a) examined this type of Hylaeus minutus Fabricius and transferred it to Dialictus (Chloralictus). The type locality is "Americae insulus", clarified subsequently to be "Americae meridionalis insulus" (Fabricius 1804). Moure (1960b) thought it was from St. Vincent. Moure and Hurd (1987) considered it a possible senior synonym of L. sanctivincenti. However,  suggests that the specimen may be from St. Thomas in the Virgin Islands, as the underside of known from the region, so the potential for additional halictid species on St. Lucia is high. Recent studies in the Greater and Lesser Antilles seem to suggest that halictid bee communities are largely distinct between islands (Engel 2001b(Engel , 2011Genaro 2001bGenaro , 2021Gibbs 2018). As such, representatives of these genera could constitute undocumented diversity. Many additional islands in the Lesser Antilles have few or no species of halictid bee known from them. Ongoing work in this area suggests that there are several additional species to describe from smaller islands in the Caribbean. Fourteen morphospecies of Halictidae were recorded from Montserrat, but none with species names (Ivie et al. 2008). In St. Kitts, the only known halictid bee is a brood parasite, but no potential hosts have been documented (Engel 2006b). Additional study of Monserrat, St. Kitts, and other islands in the Lesser and Greater Antilles is needed. This will allow future biogeographical and speciation studies of halictid bees through the Caribbean. Furthermore, baseline data are needed to assess any conservation concerns in the region. As noted previously, several species in the islands show limited distribution within islands and some have not been collected in more than a century (Gibbs 2016(Gibbs , 2018. Targeted surveys for these species would be prudent to determine their status.