Epeolus barberiellus Cockerell, 1907

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 : 35-38

10. Epeolus barberiellus Cockerell, 1907 Figs 2E, 22, 23, 96E

Epeolus barberiellus Cockerell, 1907b. Entomologist 40: 266 (♀).

Diagnosis.

The following morphological features in combination (excluding any that are specific to the opposite sex of the one being diagnosed) can be used to tell E. barberiellus apart from all other North American Epeolus except E. americanus and E. asperatus : in females, F2 is not more than 1.1 × as long as wide; the mesoscutum has distinct paramedian bands; the axilla is small to intermediate in size, not extending beyond the midlength of the mesoscutellum and the free portion is less than 1/4 as long as the entire medial length of the axilla, and like the mesoscutellum black; the mesopleuron is closely (i≤1d) and evenly punctate; T1 has a quadrangular discal patch, in dorsal view the longitudinal band is at least as wide as the breadth of the apical fascia; and the T1 and T2 apical fasciae are interrupted or at least greatly narrowed medially. In E. asperatus the mesopleuron has much denser punctures ventrolaterally (most i<1d) than that of E. barberiellus and the T3 and T4 fasciae are never complete but broken or at least greatly narrowed laterally, as well as medially into separated or narrowly connected oval patches. Epeolus barberiellus is most similar to E. americanus , but in E. americanus the pronotal lobe and legs are brown or black, not reddish orange.

Redescription.

FEMALE: Length 5.7 mm; head length 1.8 mm; head width 2.3 mm; fore wing length 5.0 mm.

Integument coloration. Mostly black; notable exceptions as follows: at least partially ferruginous on mandible, labrum, antenna, pronotal lobe, tegula, mesopleuron, metapleuron, propodeum, legs, metasomal terga (including pygidial plate), and metasomal sterna. Mandible with apex darker than rest of mandible; preapical tooth as dark as mandibular apex (difficult to see in holotype because mandible closed; described from non-type specimens). Pedicel and flagellum brown and orange in part, slightly lighter than dark brown scape. Pronotal lobe reddish brown. Tegula pale ferruginous to amber. Wing membrane subhyaline, apically dusky. Legs more extensively reddish orange than brown or black. T5 and pygidial plate reddish orange.

Pubescence. Face with tomentum densest around antennal socket. Dorsum of mesosoma and metasoma with bands of off-white to pale yellow short appressed setae. Mesoscutum with paramedian band and moderately dense pale tomentum along margins. Mesopleuron densely hairy, except for almost entirely bare circular patch occupying much of ventrolateral half of mesopleuron. Metanotum with tomentum uninterrupted, uniformly off white. T1 with median quadrangular reddish-brown discal patch enclosed by pale tomentum, except for medial separation at apex, and narrow, such that longitudinal band more than half as wide as width of discal patch in dorsal view. T2 with fascia interrupted medially and without anterolateral extensions of tomentum, although fascia broader laterally with hairs sparser basally. T3 and T4 with fasciae complete and narrowed laterally. T5 with two patches of pale tomentum lateral to and separate from pseudopygidial area. T5 with pseudopygidial area lunate, its apex more 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 not extending beyond apex of sternum by more than 1/4 MOD.

Surface sculpture. Punctures dense. Labrum with larger and sparser punctures (i=1-2d) than clypeus (i<1d). Impunctate spot lateral to lateral ocellus absent in holotype, but shiny spot present in non-type specimens. Mesoscutum, mesoscutellum, and axilla coarsely and densely rugose-punctate. Tegula densely punctate mesally (i≤1d), less so laterally (i=1-2d). Mesopleuron with ventrolateral half densely punctate (i≤1d), the interspaces shining; mesopleuron with punctures more or less equally dense throughout. Metasomal terga with punctures very fine, dense (i≈1d), evenly distributed on disc.

Structure. Labrum with pair of small subapical denticles not preceded by carinae. Frontal keel not strongly raised. Scape with greatest length 1.9 × greatest width. F2 as long as wide (L/W ratio = 1.0). Preoccipital ridge not joining hypostomal carina, from which it is separated by about 1.5-2 MOD at its terminal (difficult to see in holotype; described from non-type specimens). Mesoscutellum moderately bigibbous. Axilla small to intermediate in size, its lateral margin (L) less than half as long as mesoscutellar width (W) (L/W ratio = 0.3) and tip not extending beyond midlength of mesoscutellum; axilla with tip visible, but unattached to mesoscutellum for less than 1/4 the medial length of axilla; axilla with lateral margin relatively straight and without carina. 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, nearly as long as wide (L/W ratio = 0.8); S4 and S5 with much longer coppery to silvery subapical hairs, which individually are often darker apically; pygidial plate orange and V-shaped but apically rounded, with large deep punctures closely clustered.

Distribution.

Arizona to west Texas (Fig. 23).

Ecology.

HOST RECORDS: The host species of E. barberiellus is/are presently unknown.

FLORAL RECORDS: Labels of examined voucher specimens indicate floral associations with Aster (possibly in reference to a plant that is in a different genus now) ( Compositae ) and Sphaeralcea .

Discussion.

Epeolus barberiellus is most similar to E. americanus , from which it differs consistently only in integument coloration. Although sequenced representatives of both forms share the same BIN, specimens identified as E. barberiellus cluster separately from those identified as E. americanus (Suppl. material 2). Whereas E. americanus is widely distributed across North America, E. barberiellus appears to be restricted to the Southwestern United States (and possibly adjacent Mexico), where it replaces the much darker form that characterizes E. americanus . Taken together, these differences are indicative of divergence, and therefore the two forms are herein considered to be heterospecific. Brumley (1965) also considered E. americanus and E. barberiellus as separate species, but synonymized E. asperatus and E. melectimimus under E. americanus . In the present study, three valid species in the "americanus group" ( E. americanus , E. asperatus , and E. barberiellus ) are recognized, of which only E. asperatus has been assigned a separate BIN, suggesting that E. americanus and E. barberiellus are sister species.

The male of E. barberiellus is described here for the first time. Of the Epeolus in the "americanus group", this appears to be the least commonly collected species.

Material studied.

Type material. Primary: USA: New Mexico: Mesilla Park, 22.iv.????, C.M. Barber (holotype ♀ [USNM, catalog number: 534039]).

DNA barcoded material with BIN-compliant sequences.

Available. BOLD:AAB9110. Specimens examined and sequenced.-USA: New Mexico: Sagebrush Valley Rd (32.9500°N; 104.8333°W) (Artesia), 01-10.v.2004, M.E. Irwin (1♂, BBSL).

Non-barcoded material examined.

USA: Arizona: 2 mi SW Apache (Cochise County), 19.iv.1961, Gertsch, Rozen, and Schrammel (1♀, AMNH); 31 mi N Wickenburg, 21.iv.1967, P. Torchio and N. Youssef (1♂, LACM); 40 mi S Kingman (Mohave County), 21.iv.1967, P. Torchio and N. Youssef (1♀, BBSL); New Mexico: 12 mi N Las Cruces ( Doña Ana County), 11.iv.1965, F.D. Parker (1♂, BBSL); Texas: 9.4 mi E Cornudas (Hudspeth County), 27.iv.1998, T., S., and L. Griswold (1♀, BBSL).