Epeolus Latreille, 1802

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 : 7-10

Epeolus Latreille, 1802

Epeolus Latreille, 1802: 427. Type species: Apis variegata Linnaeus, 1758, by monotypy.

Trophocleptria Holmberg, 1886: 233, 275. Type species: Trophocleptria variolosa Holmberg, 1886, by monotypy.

Epeolus (Diepeolus) Gribodo, 1894: 80. Type species: Epeolus giannellii Gribodo, 1894, by monotypy.

Epeolus (Monoepeolus) Gribodo, 1894: 80. Type species: Apis variegata Linnaeus, by monotypy.

Pyrrhomelecta Ashmead, 1899: 66. Type species: Epeolus glabratus Cresson, 1878, by original designation and monotypy.

Argyroselenis Robertson, 1903: 284. Type species: Triepeolus minimus Robertson, 1902, by original designation and monotypy.

Oxybiastes Mavromoustakis, 1954: 260. Type species: Oxybiastes bischoffi Mavromoustakis, 1954, by original designation and monotypy.

Remarks.

In his original description, Latreille (1802) did not explain the etymology of Epeolus , but it seems likely that the name is a diminutive of Epeus/Epeius, the soldier in Greek mythology to whom building the Trojan Horse is attributed, and that it was inspired by the sinister nature of these cleptoparasitic bees. This was the first genus of Epeolini described, and ‘epeolus’ has since become the root in the names of many other nomadine and non-nomadine genera and tribes (e.g., Epeoloides Giraud ( Osirini ), Parepeolus Ducke ( Osirini ), Protepeolini , Pseudepeolus Holmberg ( Epeolini ), etc.).

Several species of Epeolus were previously described as belonging to different genera, in particular Triepeolus . On account of Rightmyer’s (2008) revision of Triepeolus , the generic placement of species that were once erroneously switched has been corrected. A few North American species were (initially or at some point in the past) described as belonging to genera that are no longer considered valid, including Argyroselenis Robertson, Phileremus (the name is a synonym of Ammobates Latreille subgenus Ammobates Latreille s. str. in Michener 2007), and Pyrrhomelecta Ashmead. These represented unnatural groupings of species by shared homoplasious morphological features: if the fore wing has two submarginal cells ( Phileremus ) instead of the usual three, if the maxillary palpus is three-segmented ( Argyroselenis ) rather than two-segmented (both states occur within Epeolus and Thalestriina , Rightmyer 2004), and if there is extensive red versus black integument coloration and reduced pubescence ( Pyrrhomelecta ).

Species of Epeolus are small to moderate-sized (body length 5.5-10.0 mm) relatively robust cleptoparasitic (epeoliform) bees. In North America, Epeolus may be confused with Triepeolus , which it resembles in general appearance, although Triepeolus may attain a much larger size (body length up to 18 mm in some species, Rightmyer 2008). The only other North American epeoline genus, Odyneropsis Schrottky, is rare (known only from the American Southwest) ( Griswold and Parker 1999) and more likely to be confused with vespid wasps (hence the root ‘odynerus’) rather than Epeolus . Comprehensive overviews of the distinguishing features of Epeolus in reference to all other Epeolini are provided in Rightmyer (2004) and Michener (2007).

Diagnosis for Epeolus in North America

(Canada and the United States). Diagnostic for female Epeolus is a very distinct S6, which is usually retracted except sometimes for a pair of convergent spatulate lateral apical processes bearing setae modified into minute, pointed denticles ( Onuferko 2017, Fig. 2A, B). Basally, the processes are separated by a large lobe-like disc, which in Triepeolus is reduced to a narrow transverse bar. In both Triepeolus ( Onuferko 2017, Fig. 2C, D) and Odyneropsis , the lateral apical processes are subparallel and bear coarse, spine-like setae. Additionally, females may be separated on the basis of the pseudopygidial area (the apicomedial region of T5 that changes slope from the rest of the tergum), which in Epeolus is covered in a silvery band of short apically rounded setae. In Triepeolus , the pseudopygidial area is usually longer than in Epeolus and in most species the setae reflect a golden color. The T5 in female Odyneropsis is unique in that it is broadly notched posteriorly and has a distinct middorsal depressed area in the shape of a pointed oval outlined by ridges ( Rightmyer 2004, fig. 180A).

Male Epeolus are more difficult to diagnose. As in females, the body lacks integumental white or yellow areas but the mesosoma and usually other tagmata have short appressed plumose white and/or yellow setae; the maxillary palpus is two or three segmented; the inner margins of the compound eyes are distinctly convergent below; the axilla is produced to a rounded lobe or angle or spine (i.e., not continuing the contour of the mesoscutellum); the distitarsi of all legs have arolia; the fore wing usually has three submarginal cells (if with two, then the second is at least nearly as long as the first), and the marginal cell is apically removed from the wing margin and much longer than the stigma; and a pygidial plate is present. In male Epeolus , the pygidial plate in most species is broadly rounded posteriorly (Fig. 2B); in Odyneropsis and Triepeolus it is usually more elongate and with a median constriction (Fig. 2F). It should be noted that males of some species of Epeolus in North America (notably E. australis Mitchell, E. flavofasciatus Smith, and some males in the "americanus group") have a very narrow and distinctly Triepeolus -like pygidial plate (Fig. 2A, C, D), as opposed to the more broadly rounded/subtruncate pygidial plate typically associated with male Epeolus (Fig. 2B). The presence of a preapical tooth of the mandible (Fig. 3B, C, D, F) (often hidden from view because the mandibles are usually closed) confirms these and other species as Epeolus ; all Triepeolus and only some Epeolus (in North America E. ainsliei , E. erigeronis , E. ilicis , E. inornatus , and E. zonatus ) lack one (Fig. 3A, E) ( Rightmyer 2004).

List of species with their proposed common names

Epeolus ainsliei Crawford, 1932 - Ainslie’s epeolus

Epeolus americanus (Cresson, 1878) - American epeolus

Epeolus andriyi Onuferko, sp. n. - Andrew’s epeolus

Epeolus asperatus Cockerell, 1909 - rough epeolus

Epeolus attenboroughi Onuferko, sp. n. - Attenborough’s epeolus

Epeolus australis Mitchell, 1962 - southern epeolus

Epeolus autumnalis Robertson, 1902 - fall epeolus

Epeolus axillaris Onuferko, sp. n. - spiny epeolus

Epeolus banksi (Cockerell, 1907) - Banks’ epeolus

Epeolus barberiellus Cockerell, 1907 - Barber’s epeolus

Epeolus basili Onuferko, sp. n. - Basil’s epeolus

Epeolus bifasciatus Cresson, 1864 - two-banded epeolus

Epeolus brumleyi Onuferko, sp. n. - Brumley’s epeolus

Epeolus canadensis Mitchell, 1962 - Canada epeolus

Epeolus carolinus Mitchell, 1962 - Carolina epeolus

Epeolus chamaesarachae Onuferko, sp. n. - five eyes crowned epeolus

Epeolus compactus Cresson, 1878 - compact epeolus

Epeolus deyrupi Onuferko, sp. n. - Deyrup’s epeolus

Epeolus diadematus Onuferko, sp. n. - Texas crowned epeolus

Epeolus erigeronis Mitchell, 1962 - fleabane epeolus

Epeolus ferrarii Onuferko, sp. n. - Ferrari’s epeolus

Epeolus flavofasciatus Smith, 1879 - yellow-banded epeolus

Epeolus floridensis Mitchell, 1962 - Florida epeolus

Epeolus gibbsi Onuferko, sp. n. - Gibbs’ epeolus

Epeolus glabratus Cresson, 1878 - smooth epeolus

Epeolus howardi Mitchell, 1962 - Howard’s epeolus

Epeolus ilicis Mitchell, 1962 - holly epeolus

Epeolus inornatus Onuferko, sp. n. - inornate epeolus

Epeolus interruptus Robertson, 1900 - interrupted epeolus

Epeolus lectoides Robertson, 1901 - Eastern prized epeolus

Epeolus lectus Cresson, 1878 - Great Plains prized epeolus

Epeolus mesillae (Cockerell, 1895) - Mesilla epeolus

Epeolus minimus (Robertson, 1902) - least epeolus

Epeolus nebulosus Onuferko, sp. n. - clouded epeolus

Epeolus novomexicanus Cockerell, 1912 - New Mexico epeolus

Epeolus olympiellus Cockerell, 1904 - Olympia epeolus

Epeolus packeri Onuferko, sp. n. - Packer’s epeolus

Epeolus pusillus Cresson, 1864 - dwarf epeolus

Epeolus rufulus Cockerell, 1941 - reddish epeolus

Epeolus scutellaris Say, 1824 - shield-backed epeolus

Epeolus splendidus Onuferko, sp. n. - polished epeolus

Epeolus tessieris Onuferko, sp. n. - Tessier’s epeolus

Epeolus zonatus Smith, 1854 - white-banded red epeolus