Epeolus lectus Cresson, 1878

Onuferko, Thomas M., 2018, A revision of the cleptoparasitic bee genus Epeolus Latreille for Nearctic species, north of Mexico (Hymenoptera, Apidae), ZooKeys 755, pp. 1-185 : 105-110

31. Epeolus lectus Cresson, 1878 Figs 65, 66, 91B, 92A, 93A

Epeolus lectus Cresson, 1878. Trans. Am. Entomol. Soc. 7: 88 (♀).

Epeolus agnatus Cresson, 1878. Trans. Am. Entomol. Soc. 7: 89 (♂).

Diagnosis.

The following morphological features in combination can be used to tell E. lectus apart from all other North American Epeolus : the mesopleuron has sparser punctures ventrolaterally (most i>1d) than in upper half, with the interspaces shining; the metasomal terga have coarse, deep punctures; and T2-T4 have complete and evenly broad fasciae. Epeolus lectus is most similar to E. lectoides , and in both species the free portion of the axilla is distinctly hooked and the pseudopygidial area of the female is distinctly campanulate with the apex <2 × the medial length, but in E. lectoides the metasomal terga have minute, shallow punctures and the T2-T4 fasciae are conspicuously narrowed or interrupted medially.

Redescription.

FEMALE: Length 9.2 mm; head length 2.3 mm; head width 3.1 mm; fore wing length 7.2 mm.

Integument coloration. Mostly black; notable exceptions as follows: partially to entirely ferruginous on mandible, antenna, tegula, axilla, mesoscutellum, legs, and meta somal sterna. Mandible with apex darker than all but extreme base; preapical tooth lighter than mandibular apex (difficult to see in the E. lectus holotype; described from non-type specimens). Flagellum brown and (except F1) slightly lighter than partially dark brown (otherwise orange) scape and F1 and entirely dark brown pedicel, primarily due to extensive pilosity on flagellum. F2 with orange spot basally. Wing membrane dusky subhyaline, slightly darker at apex. Legs from trochanter to tarsus extensively reddish orange, coxae brown.

Pubescence. Face with tomentum densest around antennal socket. Tomentum slightly sparser on clypeus; upper paraocular and frontal areas, and vertexal area mostly exposed. Dorsum of mesosoma and metasoma with bands of off-white to pale yellow short appressed setae. Mesoscutum with paramedian band. Mesopleuron with upper half sparsely hairy, ventrolateral half nearly bare. Metanotum with tomentum sparser medially, uniformly off white. T1 with discal patch elliptical and very wide, the basal and apical fasciae only narrowly joined laterally. T1 with basal and apical fasciae and T2-T3 with apical fasciae complete (T4 entirely retracted in the E. lectus holotype, but with complete fascia in non-type specimens), T2 with fascia with faint anterolateral extensions of sparser tomentum. T5 with two large patches of pale tomentum lateral to and contacting pseudopygidial area at apex. T5 with pseudopygidial area campanulate, its apex less than twice as wide as medial length, indicated by silvery setae on impressed disc of apicomedial region elevated from rest of tergum. S5 with apical fimbria of coppery to silvery hairs extending beyond apex of sternum by 1/3 MOD.

Surface sculpture. Punctures dense, but those of head and mesosoma sparser in some areas, larger, deep, and distinct. Labrum with larger punctures than clypeus, but punctures of both equally dense (i<1d). Small impunctate shiny spot lateral to lateral ocellus. Mesoscutum, mesoscutellum, and axilla very coarsely and densely punctate; the interspaces shining. Tegula very densely punctate mesally (i≤1d), less so laterally (i=1-2d). Upper half of mesopleuron and anterior margin with denser (i≤1d) punctures than rest of mesopleuron (i>1d), the interspaces shining. Metasomal terga with punctures coarse, dense (i≈1d), evenly distributed on disc; the interspaces shining somewhat.

Structure. Preapical tooth blunt and obtuse. Labrum with pair of small subapical denticles, each preceded by small discrete longitudinal ridge. Frontal keel not strongly raised. Scape with greatest length 1.7 × greatest width. F2 noticeably longer than wide (L/W ratio = 1.5). Preoccipital ridge not joining hypostomal carina, from which it is separated by no less than 1 MOD at its terminal (difficult to see in the E. lectus holotype; described from non-type specimens). Mesoscutellum moderately bigibbous. Axilla large, its lateral margin (L) half as long as mesoscutellar width (W) (L/W ratio = 0.5) and tip not extending much beyond midlength of mesoscutellum (extending to <2/3 its length in the E. lectus holotype and all examined non-type specimens; extending to ~2/3 its length in the E. agnathus holotype); axilla with tip conspicuously diverging from side of mesoscutellum, distinctly hooked, and axilla with free portion approximately half its medial length; axilla with lateral margin relatively straight and carinate. Fore wing with three submarginal cells. Pygidial plate apically truncate.

MALE: Description as for female except for usual secondary sexual characters and as follows: F2 shorter, but still longer than wide (L/W ratio = 1.2); S4 and S5 with much longer coppery to silvery subapical hairs; pygidial plate apically rounded, with large deep punctures closely clustered medially and sparser laterally, with the interspaces shining.

Distribution.

Great Plains and Mountain states east of the Continental Divide (Fig. 66).

Ecology.

HOST RECORDS: In late July 2015, I collected several specimens of this species near the Poudre River in the Roosevelt National Forest, Colorado, USA, where large numbers of Colletes females were collected and observed foraging on purple Dalea flowers. Using Stephen’s (1954) key, collected specimens were identified as being either C. robertsonii Dalla Torre or C. timberlakei Stephen, the females of which cannot be reliably distinguished morphologically, although the short triangular mesosomal spines and fine punctation on the tegulae of examined specimens coupled with their collection locality suggest they are C. timberlakei .

FLORAL RECORDS: The label of one examined voucher specimen indicates a floral association with Cryptantha cinerea var. jamesii (Torr.) Cronquist ( Boraginaceae ).

Discussion.

The names Epeolus agnathus and E. lectus were published simultaneously, although Cresson (1878) remarked that E. agnathus may be the male of E. lectus as the two specimens are structurally similar. Robertson (1902) synonymized E. agnathus under E. lectus , and separated both specimens from E. lectoides based on differences in metasomal pubescence and punctation (see diagnosis). I have examined the holotype specimens of E. lectus and E. agnathus , and agree with Robertson’s treatment. Although Robertson (1902) did not provide any justification for selecting the name E. lectus over E. agnathus , the holotype of the former is in better condition (that of E. agnathus is missing an antenna) and is female, the sex upon which most Epeolus species descriptions have been based. While Cresson’s Epeolus types include remarkably little collection data, the type locality of E. agnathus (Dakota Territory) is even more vague than that of E. lectus (Kansas).

In contrast to the similar and presumably closely related E. lectoides , E. lectus has a much more restricted range and is rare in collections. Both species are known from the Great Plains, although the range of E. lectus extends further west. In E. lectus , the metasoma has much coarser punctures than that of any other North American species in the genus, including E. lectoides , in which the metasoma has much finer and sparser punctures. In addition to this and other clear morphological differences (see diagnosis), the distinction between E. lectus and E. lectoides is supported by separate BINs for the two species.

Material studied.

Type material. Primary: USA: Dakota: H. Ulke ( E. agnathus holotype ♂ [ANSP, catalog number: 2226]); Kansas: Wilson ( E. lectus holotype ♀ [ANSP, catalog number: 2225]).

DNA barcoded material with BIN-compliant sequences.

Available. BOLD:ACZ8246. Specimens examined and sequenced.-USA: Colorado: Bellvue (40.6882°N; 105.3070°W) (N Cache La Poudre River and E Gordon Creek, Larimer County), 28.vii.2015, A.T. and T.M. Onuferko (2♀, PCYU).

Non-barcoded material examined.

USA: Colorado: Bellvue (40.6882°N; 105.3070°W) (N Cache La Poudre River and E Gordon Creek, Larimer County), 28.vii.2015, A.T. and T.M. Onuferko (3♀, PCYU); Kansas: 4 mi NW Coldwater (Comanche County), 12.vi.2002, G.A. Salsbury (1♀, KUNHM); South Dakota: Chamberlain (Brule County), 15.vi.1928, H.C. Severin (1♂, USNM).