Triepeolus obliteratus Graenicher, 1911

Onuferko, Thomas M. & Rightmyer, Molly G., 2024, A revision of the simplex species group of the cleptoparasitic bee genus Triepeolus Robertson, 1901 (Hymenoptera: Apidae), European Journal of Taxonomy 950 (1), pp. 1-106 : 48-53

Triepeolus obliteratus Graenicher, 1911

Figs 3B , 7B , 9B , 12G , 22

Triepeolus obliteratus Graenicher, 1911: 242 (♀, ♂), lectotype presently designated.

Triepeolus obliteratus – Mitchell 1962: 477 (redescription). — Veit et al. 2021: 139 (new state record, new host association).

Proposed common name

Obliterated triepeolus.

Diagnosis

The following morphological features in combination tell T. obliteratus apart from all other Triepeolus in the simplex species group: the mesopleura laterally do not have erect/suberect, simple setae or have only sparse, short (<¼ MOD), erect/suberect, simple setae in addition to the usual appressed, branched setae ( Figs 9B , 22A, C ); the legs, at least from coxae to femora, are partially to predominantly dark brown/black ( Figs 3B , 9B , 22A–C ); the trochanters are normal (i.e., not tuberculate) ( Fig. 9B ); the dorsum of the mesosoma and metasoma have bands of pale-gray to white/off-white tomentum ( Fig. 22 ); and the T1 discal patch is transversely oblong or elliptic ( Fig. 22B ). Triepeolus obliteratus most closely resembles T. oblongimacula sp. nov. and T. rhododontus , but in the latter two species the dorsum of the mesosoma and metasoma have bands of pale-yellow tomentum, the legs may be entirely reddish orange from trochanters to tarsi, and the pseudopygidial area of the female may be partially to predominantly reddish orange (as opposed to entirely dark brown/black; Fig. 22D ), and in T. rhododontus the axillae commonly (as opposed to never) have reddish tips. Males of T. obliteratus also closely resemble those of T. eliseae Rightmyer, 2017 and T. michiganensis Mitchell, 1962 , but in the latter two species, which are not in the simplex species group, the pygidial plate may have a well-defined basal transverse ridge, in T. eliseae the propodeal triangle is mostly covered in dense, appressed pale setae (as opposed to glabrous; Fig. 7B ), and in T. michiganensis the clypeus has a well-defined glabrous midline (absent in T. obliteratus ; Fig. 3B ).

Etymology

The specific epithet was inspired by the fore wings each having the second submarginal crossvein incomplete in the lectotype and lectoallotype of this species, as indicated by Graenicher’s (1911) remark that “[b]oth of the specimens have the second transverse cubital nervure more or less obliterated in both wings”.

Material examined

Primary type material

USA • ♀, lectotype; Wisconsin, Yellow River , Burnett County; 28–31 Jul. 1909; MPM ENT6434 .

Secondary type material

USA • 1 ♂, lectoallotype; Wisconsin, Prescott , Pierce County; 13–19 Jul. 1910; MPM ENT6435 .

DNA barcoded material

Available. BIN: BOLD:AEE4216. Specimens examined and sequenced:

CANADA – Manitoba • 1 ♀; Spruce Woods Provincial Park ; 49.6649° N, 99.2774° W; 30 Jul. 2019; T.M. Onuferko leg.; BOLD sample ID: CMNTO_003 ; TOPC . – Saskatchewan • 1 ♀; Avonlea Badlands ; 50.0246° N, 104.9831° W; 11 Jul.–1 Aug. 2019; RSM Bee Team leg.; BOLD sample ID: CCDB-38770 E 10; RSKM RSKM _ ENT_E-225802 • 1 ♀; Douglas Provincial Park ( Elbow ); 51.0467° N, 106.4423° W; 22 Jul. 2019; T.M. Onuferko leg.; BOLD sample ID: CMNTO_001 ; CMNC • 1 ♀; Herbert ; 50.4195° N, 107.2189° W; 15 Aug. 2013; C.S. Sheffield et al. leg.; BOLD sample ID: CCDB-32640 H07 ; RSKM RSKM_ENT_E-110579 • 1 ♀; near Avonlea ; 50.0241° N, 104.9831° W; 30 Jun.–7 Jul. 2017; C.S. Sheffield and R. Oram leg.; BOLD sample ID: CCDB-38770 F01 ; RSKM RSKM_ENT_E-185267 • 1 ♂; same data as for preceding; 30 Jun.–7 Jul. 2017; C.S. Sheffield, R. Oram, J. Kalyniuk, and G. Wihlidal leg.; BOLD sample ID: CCDB-38770 E11 ; RSKM RSKM_ENT_E-185259 • 1 ♂; same data as for preceding; 30 Jun.–7 Jul. 2017; C.S. Sheffield, R. Oram, J. Kalyniuk, and G. Wihlidal leg.; BOLD sample ID: CCDB-38770 E12 ; RSKM RSKM_ENT_E-185261 .

USA – Iowa • 1 ♀; Butler County; 42.6260° N, 92.6896° W; 19 Jul. 2019; M. Vandever leg.; BOLD sample ID: CMNTO_057 ; CSUC . – Massachusetts • 1 ♀; Ashburnham , Worcester County; 42.7050° N, 71.9270° W; 6 Aug. 2015; M.F. Veit leg.; BOLD sample ID: CMNTO_249 ; TOPC . – New Hampshire • 1 ♂; Crotched Mountain Trail ( Greenfield ), Hillsborough County; 22 Jul. 2016; M.F. Veit leg.; BOLD sample ID: CMNTO_250 ; TOPC .

Non-barcoded material

CANADA – Alberta • 2 ♀♀; 8.5 km E of Clyde , Westlock County; 54.1661° N, 113.5003° W; 21 Jul. 2010; M. Buck leg.; RAM pmae00116017 , pmae00116018 • 1 ♀; same data as for preceding; 21 Jul. 2010; M. Buck and Widen leg.; RAM pmae00116618 • 1 ♀; 15 km SW of Edson ; 53.4917° N, 116.6044° W; 21 Jul. 2021; M. Buck leg.; RAM pmae00160149 • 1 ♀; Bridge Lake Natural Area , Westlock County; 54.1772° N, 113.4886° W; 27 Jul. 2011; M. Buck leg.; RAM pmae00120258 • 1 ♂; Opal Dunes , Thorhild County; 54.0075° N, 113.2681° W; 24 Jul. 2009; M. Buck and Palumbo leg.; RAM pmae00111591 • 1 ♀; Ukalta Dunes , Lamont County; 53.9747° N, 112.5072° W; 6 Aug. 2010; S. Widen leg.; RAM pmae00117232 • 1 ♀; Wainwright Municipal District, Ribstone Creek Heritage Rangeland Natural Area ; 52.7269° N, 110.3667° W; 8 Jul. 2009; M. Buck leg.; RAM pmae00111947 . – Manitoba • 2 ♀♀; 19.6 km WSW of Virden ; 49.8014° N, 101.1961° W; 23 Jul. 2021; O. Abel leg.; CMNC • 1 ♂; 2.5 km E of Portage Sand Hills Wildlife Management Area on Road 54 N, Rural Municipality of Portage la Prairie; 49.7990° N, 98.2170° W; 5 Jul. 2019; E. Hanuschuk leg.; WRME WRME_EJH02370 • 1 ♀; 4.5 km SE of Portage La Prairie , Rural Municipality of Portage la Prairie ; 49.9300° N, 98.2620° W; 16 Jul. 2018; E. Hanuschuk leg.; WRME JBWM0391741 • 1 ♀; 5 mi W of Carberry ; 9 Aug. 1958; N.B. Chillcott leg.; CNC • 1 ♂; 6.5 km E of Portage Sand Hills Wildlife Management Area on Road 54 N, Rural Municipality of Portage la Prairie; 49.7980° N, 98.1650° W; 16 Aug. 2019; E. Hanuschuk leg.; WRME WRME_EJH02720 • 1 ♂; 7 km E of Marchand , Rural Municipality of Reynolds ; 49.4440° N, 96.2700° W; 22 Jul. 2020; J. Gibbs leg.; WRME WRME0507584 • 1 ♀; Bald Head Hills (13 mi N of Glenboro ); 9 Aug. 1958; R.B. Madge leg.; CNC • 1 ♂; Birds Hill Provincial Park ; 50.0100° N, 96.9090° W; 2 Jul. 2020; J. Gibbs leg.; WRME WRME0507876 • 1 ♀; Birds Hill Provincial Park ; 50.0115° N, 96.9065° W; 12 Aug. 2017; J. Gibbs and G.Y. Nozoe leg.; WRME JBWM0362976 • 1 ♀; Linden , Rural Municipality of Taché ; 49.6790° N, 96.8890° W; 9 Aug. 2019; S. Shukla-Bergen leg.; WRME WRME0501597 • 3 ♀♀; Oak Hammock Marsh , Rural Municipality of Rockwood ; 50.1750° N, 97.1550° W; 26 Aug. 2020; J. Gibbs leg.; WRME WRME0508600 , WRME0508602 , WRME0508637 • 1 ♀; Rd 13E ( Oak Hammock Marsh Wildlife Management Area ), Rural Municipality of Rockwood; 50.1820° N, 97.1610° W; 7 Aug. 2019; E. Hanuschuk leg.; WRME WRME_EJH01940 • 1 ♂; Shilo ; 49.8124° N, 99.5131° W; 12 Jul. 2011; K. Wareham and S. Patterson leg.; WRME JBWM0385547 • 1 ♀; Spirit Hills ; 49.6600° N, 99.2900° W; 25 Aug. 1978; T.D. Galloway leg.; WRME JBWM0296424 • 1 ♀; Spirit Sands ( Spruce Woods Provincial Park ); 49.6600° N, 99.2800° W; 2 Jul. 2018; J. Gibbs leg.; WRME JBWM0379545 • 2 ♂♂; same data as for preceding; 6 Jul. 2019; J. Gibbs leg.; WRME JBWM0422817 , JBWM0422819 • 1 ♂; St. Adolphe, Rural Municipality of Ritchot ; 49.6550° N, 97.1140° W; 12 Jul. 2019; S. Shukla-Bergen leg.; WRME JBWM0425506 • 1 ♀; Ste. Agathe ; 29 Aug. 1969; Boyle leg.; LEM • 1 ♂; Transcona; 8 Aug. ??24; G.S. Brooks leg.; CNC 427182 • 1 ♂; Vita, Rural Municipality of Stuartburn ; 49.1490° N, 96.6460° W; 11 Jul. 2019; S. Shukla-Bergen leg.; WRME JBWM0425564 • 1 ♀; Winnipeg ; 21 Aug. 1935; R.R. Lejeune leg.; WRME JBWM0296432 . – Saskatchewan • 1 ♀; 21 mi W of Moose Jaw ; 28 Jul. 1972; C.D. Michener leg.; KUNHM M.G.R. Database No. 584 • 1 ♀; NCC’s Buffalo Pound property; 50.7293° N, 105.5985° W; 3 Aug. 2021; C.S. Sheffield and K. Palmier leg.; RSKM RSKM_ENT_E-125601 • 1 ♀; Nipawin ; 18 Jul. 1952; W.P. Stephen leg.; WRME JBWM0295628 .

USA – Illinois • 1 ♀; Richardson Wildlife Foundation , Lee County; 9 Jul. 1996; J.K. Bouseman leg.; INHS 441217 / 362391 • 1 ♂; Sand Ridge State Forest (4 mi SW of Forest City), Mason County; 15 Jul. 1982; E. Miliczky leg.; INHS 7784 . – Massachusetts • 1 ♂; 1.1 mi SE of Pepperell ( Groton ), Middlesex County; 28 Jul. 2008; M.F. Veit leg.; TOPC WHD00000335 • 1 ♂; 1.8 mi NE of Townsend , Middlesex County; 28 Jul. 2008; M.F. Veit leg.; TOPC WHD00000334 • 1 ♀; Ashburnham , Worcester County; 42.7050° N, 71.9270° W; 9 Aug. 2014; M.F. Veit leg.; TOPC • 1 ♀; Groton , Middlesex County; 42.6410° N, 71.5275° W; 15 Aug. 2009; M.F. Veit leg.; TOPC WHD00000332 • 1 ♂; same data as for preceding; 15 Aug. 2009; M.F. Veit leg.; TOPC WHD00000337 . – Minnesota • 1 ♂; 6 mi SW of Detroit Lakes , Becker County; 30 Jul. 1981; J.R. Powers leg.; EMEC M.G.R. Database No. 495 . – New Hampshire • 1 ♀; Albany , Carroll County; 43.9944° N, 71.3694° W; 25 Jul. 2010; M.F. Veit leg.; TOPC WHD00000333 • 1 ♀; Ashuelot (power line row), Cheshire County; 42.7930° N, 72.4210° W; 9 Aug. 2017; M.F. Veit leg.; BIML • 1 ♀; Pelham , Hillsborough County; 42.7027° N, 71.3047° W; 30 Jul. 2009; M.F. Veit leg.; TOPC WHD00000331 • 1 ♂; same data as for preceding; 30 Jul. 2009; M.F. Veit leg.; TOPC WHD00000336 . – New Jersey • 1 ♂; USNM M.G.R. Database No. 497 • 1 ♂; USNM M.G.R. Database No. 497 . – North Carolina • 1 ♀; Black Mountains; AMNH Ac. 33827 /M.G.R. Database No. 598 • 1 ♀, T. junctus paratype; Fayetteville ; 2 Oct. 1941; H.E. Evans leg.; CUIC Cornell U No. 3927/M.G.R. Database No. 527 • 2 ♀♀; Moore County; 8 Oct. 1964; B.S. Heming leg.; DEBU debu01089133 , debu01089136 • 1 ♀; same data as for preceding; 8 Oct. 1964; J.F. Cornell leg.; DEBU debu01089130 • 1 ♀; Swannanoa ; 3 Sep. 1924; J.C. Crawford leg.; USNM M.G.R. Database No. 528 . – North Dakota • 1 ♀; 13 mi NW of Inkster , Grand Forks County; 17 Jul. 1955; W.E. LaBerge leg.; KUNHM M.G.R. Database No. 585 • 1 ♀; 13 mi NW of Inkster , Grand Forks County; 17 Jul. 1956; W.E. LaBerge leg.; KUNHM M.G.R. Database No. 599 • 1 ♀; Grands Forks ; 3 Aug. 1912; O.A. Stevens leg.; USNM 3404 /M.G.R. Database No. 586 • 1 ♀; Perth ; 20 Aug. 1910; O.A. Stevens leg.; AMNH 6480 /M.G.R. Database No. 587 . – Oklahoma • 1 ♀; Fort Cobb Wildlife Management Area , Caddo County; 35.2220° N, 98.5180° W; 6 Oct. 2023; S. O’Dell and I. Gonzales leg.; OKBS OKBS.POL.13827 .

Non-preserved material

CANADA – Manitoba • 1 ♀; Spruce Woods Provincial Park ; 49.6635° N, 99.2894° W; 21 Aug. 2018; P. Tavares obs.; iNaturalist record #15971912 . – Saskatchewan • 1 ♂; Division No. 6 ; 18 Jul. 2020; L. Pyle obs.; iNaturalist record #53926803 .

USA – Iowa • 1 ♂; State Center ; 10 Aug. 2021; T. Grant obs.; iNaturalist record #90756016 . – Massachusetts • 1 ♀; Weir Hill Reservation, North Andover ; 42.6926° N, 71.1065° W; 21 Aug. 2019; M. McCarthy obs.; iNaturalist record #40378120 . – Minnesota • 1 ♀; Park Point, Duluth ; 46.7267° N, 92.0463° W; 30 Aug. 2022; “ dexternienhaus ” obs.; iNaturalist record #133398524 . – New Hampshire • 1 – 3 ♀♀; Rockingham County; Jul. 2021; C. Prieto obs.; iNaturalist record #87793484, #189067399, #189067405 • 1 ♀; same data as for preceding; Jul. 2021; C. Prieto obs.; iNaturalist record #189368519 .

Redescription

MEASUREMENTS OF LECTOTYPE. Body length 8.7 mm; ITW 1.8 mm; head length 2.0 mm; head width 2.8 mm; fore wing length 6.2 mm.

Both sexes

INTEGUMENT COLORATION. Dark brown to black except as follows. Mandible with middle third; labrum along apical and lateral margins; scape, pedicel, and F1 to some extent (entirely dark brown/black in some non-type specimens); pronotal lobe (entirely dark brown/black in some non-type specimens); tegula; coxae to femora to some extent; tibiae (excluding brown meso- and metatibial spurs) predominantly; tarsi entirely; metasomal terga laterally; and metasomal sterna to some extent orange. F2 with orange spot basally. Fore wing membrane subhyaline, apically dusky. Hind wing membrane dusky subhyaline to hyaline. Pygidial plate to some extent reddish brown.

PUBESCENCE. Face with tomentum densest around antennal socket. Tomentum slightly sparser on clypeus; upper paraocular and frontal areas and vertexal area mostly exposed. Pronotal collar with tomentum uniformly off-white/pale gray. Mesoscutum with well-defined paramedian band of off-white to pale-gray tomentum; pale tomentum otherwise mostly restricted to lateral and posterior margins. Mesopleuron with pale-gray to white/off-white, appressed, branched setae; upper half densely setose, except behind pronotal lobe, with setae slightly sparser on hypoepimeral area; ventrolateral half sparsely setose. Metanotum with tomentum uninterrupted, uniformly off-white. Propodeal triangle mostly glabrous, with (pale) setae restricted to small lateral patches. Metasomal terga with bands of off-white/pale-gray tomentum. T1 with basal transverse band interrupted medially, apical transverse band narrowly interrupted medially, transverse bands subparallel, discal patch transversely oblong or elliptic. T2–T4 with apical transverse bands complete and medially somewhat removed from apical margins of terga, that of T2 with pair of basomedially convergent anterolateral extensions. S2–S3 with medially interrupted apical transverse bands of white tomentum (reduced to posterolateral patches in lectotype and multiple non-type specimens).

SURFACE SCULPTURE. Labrum coarsely and densely (most i <1d) rugose-punctate. Clypeus densely punctate (most i <1d) but interspaces well defined, shining; with many small punctures among larger ones. Vertexal area somewhat sparsely punctate (some i>2d), especially around ocelli. Mesoscutum, mesoscutellum, and axilla with punctures more or less equally dense and nearly contiguous (most i <1d). Mesopleuron with punctures in upper half nearly contiguous and denser (i <1d) than in ventrolateral half (i ≤2d); interspaces shining where punctures not contiguous; punctures similar in size throughout. Discs of metasomal terga with punctures very fine, dense (i≈ 1d), and evenly distributed; interspaces shining somewhat.

STRUCTURE. Labrum with pair of small subapical denticles, each preceded by discrete longitudinal ridge. Pronotal collar rather short (medial length ~⅔ MOD). Mesoscutellum moderately bigibbous. Axilla extending little if at all beyond midlength of mesoscutellum; tip distinctly pointed, but mesally unattached to mesoscutellum for less than 2/5 medial length of axilla; lateral margin somewhat arcuate. Fore wing with second submarginal crossvein incomplete and thus two submarginal cells in lectotype and lectoallotype; three submarginal cells in non-type specimens.

Female

Paramedian band tapering slightly toward but not attaining anterior margin of mesoscutum. T5 with concave apical margin and large patch of white/off-white tomentum on each side lateral to pseudopygidial area. Pseudopygidial area with triangular region of posteriorly directed coppery to silvery setae within larger trapezoidal space of posteriorly directed dark brown setae. Pygidial plate apically truncate. S4 with apical transverse band of white tomentum. S5 straight in lateral view, with apical fimbria of coppery bristle-like setae.

Male

Paramedian band anteriorly joined to lateral transverse band of equally dense off-white to pale-gray tomentum along anterior margin of mesoscutum. T5 with complete apical transverse band of off-white to pale-gray tomentum. T6 with complete apical transverse band of white/off-white tomentum. Pygidial plate relatively flat and apically rounded, with lateral margin somewhat sinuate. S4–S5 each with apical/ subapical fringe of dense, long (> 1 MOD), curved, predominantly coppery brown setae, contrasting with apical transverse bands of white tomentum of preceding sterna, those of S4 coppery to silvery laterally.

Distribution

Eastern United States to Canada’s Prairie Provinces ( Fig. 12G ).

Ecology

Host records

Triepeolus obliteratus has been observed and photographed (in 2014 and 2015) at a nest aggregation of Melissodes apicatus Lovell & Cockerell, 1906 ( Hymenoptera : Apidae : Eucerinae ) in Ashburnham, Massachusetts ( Veit et al. 2021). That M. apicatus is not known to occur west of Ontario in Canada ( Ascher & Pickering 2023) suggests that T. obliteratus takes as hosts multiple species. Triepeolus obliteratus has been collected with T. pectoralis (Robertson, 1897) at a nest aggregation of M. druriellus (Kirby, 1802) in Birds Hill Provincial Park in Manitoba (J. Gibbs, pers. com. 2020).

Floral records

Images on iNaturalist and labels of examined voucher specimens indicate that this species has been collected from the following flowering plant species: in Asteraceae , Crepis tectorum L., Erigeron sp. or spp., Euthamia graminifolia (L.) Nutt., Gaillardia sp. , Grindelia squarrosa , Heterotheca villosa (Pursh) Shinners , Rudbeckia sp. , R. hirta L., Solidago sp. or spp., S. mollis Bartlett , and Verbesina encelioides ; in Brassicaceae Burnett , canola ( Brassica sp. ); and in Fabaceae , Dalea purpurea Vent. , Melilotus albus , and Trifolium repens L.

Remarks

Graenicher (1911) described T. obliteratus from both sexes, represented by two syntypes at the MPM. Since Graenicher (1911) provided a more complete description of the female and since females are more easily recognized as members of the simplex species group, the female syntype is herein designated as the lectotype of T. obliteratus whereas the male is recognized as the lectoallotype.

In both the lectotype and lectoallotype, the second submarginal crossvein is incomplete in both fore wings. Although Mitchell (1962) considered this feature to be diagnostic in his key to species of Triepeolus of the Eastern United States, this feature does not reliably distinguish T. obliteratus from any similar-looking Triepeolus , and in most exemplars the fore wings each have three submarginal cells with complete submarginal crossveins. Cases of intraspecific variation in the number of submarginal cells and reduction of submarginal crossveins are known in many other bees, including cleptoparasitic apids (reviewed by Scarpulla 2018).

Triepeolus obliteratus is the most commonly collected species in the T. simplex group in Canada.

Figures

Fig. 3. Head of male, frontal view. A. Triepeolus michiganensis Mitchell, 1962 (CNC 719805), which has a strong glabrous clypeal midline (blue arrow). B. T. obliteratus Graenicher, 1911 (WRME WRME_ EJH02370), which does not have a glabrous clypeal midline.

Fig. 7. Mesosoma of male, posterior view. A. Triepeolus eliseae Rightmyer, 2017 (INHS 356997), in which the propodeal triangle is mostly covered in dense, appressed pale setae.B. T. obliteratus Graenicher, 1911 (WRME WRME_EJH02370), in which the propodeal triangle is mostly to entirely glabrous.

Fig. 9. Right pro- and mesotrochanters of male (anterior facing right). A. Triepeolus tuberculifer Onuferko, Rightmyer & Roig-Alsina, 2024, allotype (FSCA M.G.R. Database No. 3704), showing distinct protuberances (blue arrows). B. T. obliteratus Graenicher, 1911 (WRME WRME_EJH02370). C. T. oblongimacula sp. nov., allotype (BOLD sample ID: CMNTO_298; PCYU PCYU-SD09:28). D. T. rhododontus Cockerell, 1921 (BOLD sample ID: CMNTO_139; PCYU).

Fig. 12A–D (continued on next page). Distribution maps. A. All species in the Triepeolus simplex group. B. T. apache sp. nov. C. T. eumeniformis sp. nov. D. T. hirsutus sp. nov. Approximate geographic ranges are indicated in orange and were estimated from occurrence records known to the authors (yellow and blue circles, with the latter indicating localities of DNA barcoded specimens).

Fig. 22. Triepeolus obliteratus Graenicher, 1911. B, D. Female (BOLD sample ID: CMNTO_003; TOPC). A. Female (BOLD sample ID: CMNTO_001; CMNC), habitus, lateral view. B. Habitus, dorsal view. C. Male (CNC 427182), habitus, lateral view. D. Pseudopygidial area, dorsal view.