Triepeolus nemoralis ( Holmberg, 1886 )

Onuferko, Thomas M., Rightmyer, Molly G., Melo, Gabriel A. R. & Roig-Alsina, Arturo, 2024, A revision of the South American species of the cleptoparasitic bee genus Triepeolus Robertson, 1901 (Hymenoptera: Apidae), European Journal of Taxonomy 931, pp. 1-50 : 27-31

Triepeolus nemoralis ( Holmberg, 1886)

Figs 1F , 3B , 11 , 13B

Doeringiella nemoralis Holmberg, 1886: 280 (♀).

Epeolus merus Brèthes, 1909: 250 (♂), syn. nov.

Epeolus merus – Schrottky 1913: 265 (in regional checklist).

Triepeolus nemoralis – Roig-Alsina 1989: 578.

Diagnosis

The following morphological features in combination tell T. nemoralis apart from all other South American Triepeolus : the T1 basal band is arched, continuous with (and indistinguishable from) the lateral longitudinal bands, and mesally concave on each side, such that the discal patch is semicircular ( Fig. 11B ); the mesoscutum has a large anteromedial ovate patch of yellow tomentum ( Fig. 3B ), which may be sparser medially such that the patch is suggestive of ill-defined paramedian bands ( Fig. 11B ); and T2–T4 have complete apical transverse bands of yellow tomentum ( Figs 3B , 11B ). Triepeolus nemoralis most closely resembles specimens of T. alvarengai without an apical transverse band on T1 and T. mexicanus (Cresson, 1878) , the latter of which is known only from North and Central America, but in T. alvarengai the mesoscutum has well-defined paramedian bands and in T. mexicanus pale tomentum on the mesoscutum is restricted to the lateral and posterior margins. Males of T. nemoralis also closely resemble those of T. flavipennis , but in T. flavipennis the mesoscutum has well-defined paramedian bands and the pair of anterolateral patches of pale tomentum on T1 are mesally convex, such that the discal patch forms a trapezoid or triangle with concave anterolateral sides. This species is also very similar in overall appearance to Epeolus luteipennis , and in both species the mesoscutum has a large anteromedial patch of yellow tomentum as opposed to well-defined paramedian bands, but both sexes of T. nemoralis are easily told apart from any similar-looking Epeolus by their simple mandibles; in E. luteipennis and all other South American Epeolus , the mandibles each have a distinct preapical tooth.

Etymology

Although Holmberg (1886) did not explain the etymology of his Doeringiella nemoralis , the specific epithet seemingly alludes to the habitat (grove or woodland) in which the type of this species was collected.

Material examined

Primary type material

ARGENTINA • ♀, holotype of D. nemoralis ; Formosa, Formosa ; Mar. 1885; E.L. Holmberg leg.; MACN (not examined, destroyed) .

PARAGUAY • ♂, holotype of E. merus ; Cordillera, San Bernardino (Chaco, Alto Paraguay according to the original description); K. Fiebrig leg.; MACN 10136 .

Non-type material

ARGENTINA • 1 ♀; Autonomous City of Buenos Aires ; 1918; A. Frers leg.; MACN • 1 ♀; Autonomous City of Buenos Aires, Jardín Botánico Carlos Thays (Palermo); 20 Jan. 2020; R.A. González Vaquero and Z. Cairey leg.; FAUBA 327 • 1 ♀ (studied from images); same collection data as for preceding; 3 Feb. 2020; R.A. González Vaquero and Z. Cairey leg.; FAUBA 416 • 1 ♂ (studied from images); same collection data as for preceding; 27 Feb. 2020; R.A. González Vaquero and Z. Cairey leg.; FAUBA 596 • 1 ♀; Buenos Aires, San Isidro ; 20 Feb. 1950; MACN • 2 ♀♀; Buenos Aires, San Pedro, Vuelta de Obligado ; 33.6817° S, 59.8100° W; 13 Dec. 2012; C. and A. Roig leg.; MACN • 1 ♂; Santa Fe, Santa Fe ; 27 Feb. 1930; Bridarolli leg.; MACN .

BOLIVIA • 2 ♀♀, 1 ♂; Santa Cruz, Pedra Branca ; Apr.; ANSP .

BRAZIL • 1 ♂; Espírito Santo, Linhares; Jan. 1962; C. Elias leg.; DZUP • 1 ♀; Mato Grosso, Cáceres; 12 Mar. 1985; C. Elias leg.; DZUP • 1 ♀, 3 ♂♂; Paraná, Matinhos; 25.7667° S, 48.5833° W; 3 Mar. 2002; G.A.R. Melo and J.S. Moure leg.; DZUP • 1 ♂; Roraima, Surumu; Nov. 1966; M. Alvarenga leg.; DZUP • 1 ♀; Santa Catarina, Florianópolis; 2 Mar. 2001; E.P. Feja leg.; DZUP • 1 ♀; São Paulo, Barueri; Mar. 1958; K. Lenko leg.; DZUP • 1 ♂; same collection data as for preceding; Apr. 1958; K. Lenko leg.; DZUP .

COLOMBIA • 1 ♀; Bolívar, Zambrano ; 7 Jun. 1994; IFML • 1 ♂; Cesar, Valledupar; 11 Jul. 1968; B. Malkin leg.; AMNH • 1 ♂ (studied from images); Meta, Vereda La Balsa, Puerto López ; 27 Jul. 1983; A. Becerra leg.; ICN 101501 • 2 ♂♂; Valle del Cauca, Cali; 11 Feb. 1935; H.F. Schwarz leg.; AMNH • 1 ♀; Valle del Cauca, Hormiguero, Cali ; 14 Jan. 1935; H.F. Schwarz leg.; AMNH • 1 ♂; Valle del Cauca, Lobo Guerrero ; 20 Oct. 1977; C. García leg.; DZUP • 2 ♂♂; Valle del Cauca, Near Lobo Guerrero ; 6 Oct. 1976; M. Breed leg.; KUNHM .

GUYANA: 1 ♂; 1908; J. Rodway leg.; NHMUK • 2 ♂♂; Demerara-Mahaica, Pln. Cane Grove ; 20 Jul. 1946; H.C. James leg.; NHMUK .

TRINIDAD AND TOBAGO • 1 ♂; Tunapuna–Piarco, Curepe (Trinidad); 20 Apr. 1961; N. Gopaul leg.; CNC 1801912 .

Redescription

MEASUREMENTS OF HOLOTYPE OF E. MERUS . Body length 10.7 mm; ITW 2.3 mm; head length 2.5 mm; head width 3.4 mm; fore wing length 9.4 mm.

Both sexes

INTEGUMENT COLORATION. Dark brown to black except as follows. Mandible with middle quarter in basal half reddish brown (basal half entirely reddish brown in some non-type specimens). Scape to some extent, pedicel and F1 extensively, and tegula orange. F2 with orange spot basally. Antenna entirely dark brown in some non-type specimens. Fore wing membrane dusky subhyaline throughout. Hind wing membrane dusky subhyaline to hyaline. Legs to some extent reddish brown in holotype of E. merus ; dark brown to black in some non-type specimens. Pygidial plate 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 pale yellow laterally and black medially (uniformly bright yellow in some non-type specimens). Mesoscutum with large anteromedial ovate patch of pale-yellow tomentum, slightly separated from anterior margin (setae rather diffuse and patch thus ill-defined in holotype of E. merus ; well-defined in some non-type specimens); pale tomentum otherwise mostly restricted to lateral and posterior margins. Mesopleuron with off-white, appressed, branched setae; densely setose just below scrobal groove (upper half otherwise sparsely setose); ventrolateral half nearly bare, except along margins. Metanotum with tomentum uninterrupted, uniformly off-white (black medially in some non-type specimens). Propodeal triangle mostly glabrous, with (pale) setae restricted to small lateral patches. T1 with basal transverse band of pale-yellow tomentum complete (separated medially into pair of anterolateral patches in some non-type specimens), continuous with (and indistinguishable from) lateral longitudinal band, forming arch around semicircular discal patch. T2–T4 with complete apical transverse bands of bright yellow tomentum without well-defined anterolateral extensions, although T2–T3 with faint lateral longitudinal bands of diffuse off-white setae in some non-type specimens. S2–S3 with apical transverse bands of white tomentum.

SURFACE SCULPTURE. Labrum and clypeus with punctures equally dense and nearly contiguous (most i <1d). Vertexal area densely rugose-punctate (most i <1d). Mesoscutum, mesoscutellum, and axilla with punctures more or less equally dense (i≤ 1d); interspaces well defined, shining. Mesopleuron with punctures in upper half denser (most i ≤ 1d) than in ventrolateral half (i ≤3d), where punctures irregularly distributed; 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 somewhat dull due to tessellate surface microsculpture.

STRUCTURE. Labrum with pair of small subapical denticles. Pronotal collar rather short (medial length ~ ⅔ MOD). Mesoscutellum moderately bigibbous.Axilla extending beyond midlength of mesoscutellum but not as far back as its posterior margin; tip distinctly pointed and hooked (i.e., concave along medial margin), but mesally unattached to mesoscutellum for less than ⅖ medial length of axilla; lateral margin somewhat sinuate.

Female

Mesoscutum with ill-defined paramedian band among diffuse pale-yellow setae in some non-type specimens. T5 with concave apical margin and large patch of pale-yellow tomentum on each side lateral to pseudopygidial area. Pseudopygidial area with underlying integument extensively orange, forming rounded triangle with concave sides, with orange spinelike setae laterally. 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; S5 otherwise covered in off-white tomentum.

Male

T5–T6 with complete apical transverse bands of bright yellow tomentum. Pygidial plate relatively flat and apically rounded. S4–S5 each with apical/subapical fringe of dense, long (> 1 MOD), curved, coppery setae, contrasting with apical transverse bands of white tomentum of preceding sterna.

Distribution

Northern and eastern South America ( Fig. 1F ).

Ecology

Host records

Unknown.

Floral records

This species has been collected from the flowers of Grindelia pulchella Dunal ( Asteraceae ), Verbena gracilescens (Cham.) Herter ( Verbenaceae ), and V. intermedia Gillies & Hook. (R.A. González-Vaquero, personal communication, 2022). The label of one examined voucher specimen further indicates that this species has been collected from Ludwigia adscendens (L.) H.Hara.

Remarks

The type of D. nemoralis is meant to be at the MACN but has been destroyed ( Moure & Melo 2007). In a revision of Doeringiella, Roig-Alsina (1989) indicated that “ D. nemoralis should be called Triepeolus nemoralis (Holmberg) (new combination)” based on its description. The ill-defined spots (of pale tomentum) on the mesoscutum, (single) medially narrowed yellow band on T1, complete golden bands on T2–T4, and orange-squamous T5 (in reference to the pseudopygidial area and underlying integument coloration) describe a single species of Triepeolus in South America (in the T. simplex species group).

This species was later described under the name Epeolus merus (by Brèthes 1909) from a male specimen, supposedly from Alto Paraguay in the Paraguayan Chaco (or Western Region), but this does not correspond with the locality given on the collection label (i.e., San Bernardino, Paraguay) ( Fig. S10D in Supp. file 2). Although male, the holotype of E. merus closely matches the original description of D. nemoralis (based on the female) and both are regarded as belonging to the same species, so E. merus is herein established as a junior synonym of D. nemoralis (= T. nemoralis ).

Figures

Fig. 1. Occurrence records (yellow circles) of species of Triepeolus Robertson, 1901 represented in South America. A. T. alvarengai Moure, 1955. B. T. atoconganus Moure, 1955. C. T. buchwaldi (Friese, 1908). D. T. cecilyae Packer, 2016. E. T. flavipennis (Friese, 1916). F. T. nemoralis (Holmberg, 1886). G. T. osiriformis (Schrottky, 1910). H. T. rufotegularis (Ashmead, 1900). I. T. tuberculifer Onuferko, Rightmyer & Roig-Alsina sp. nov.

Fig. 3. Triepeolus spp., habitus, dorsal view. A. T. alvarengai Moure, 1955 female specimen (MACN) in which T1 has both basal and apical transverse bands. B. T. nemoralis (Holmberg, 1886) male specimen (DZUP) in which much of T1 is covered in pale-yellow tomentum.

Fig. 11. Triepeolus nemoralis (Holmberg, 1886). A–B. Female (FAUBA 327). A. Habitus, lateral view. B. Habitus, dorsal view. C. Male (CNC 1801912), habitus, lateral view. D. Female (MACN) pseudopygidial area, dorsal view.

Fig. 13. Axillae and mesoscutellum of male, dorsal view. A. Triepeolus flavipennis (Friese, 1916) (PCYU). B. T. nemoralis (Holmberg, 1886) (CNC 1801912). C. T. osiriformis (Schrottky, 1910) (AMNH M.G.R. Database No. 1329). D. T. tuberculifer Onuferko, Rightmyer & Roig-Alsina sp. nov., allotype (FSCA M.G.R. Database No. 3704).

Fig. 10. Triepeolus flavipennis (Friese, 1916). A. Female (CNC 753863), habitus, lateral view. B. Female (CNC 808414), habitus, dorsal view. C. Male (PCYU), habitus, lateral view. D. Female (CNC 808413) pseudopygidial area, dorsal view.