Bembecinus rhopaloceroides (Arnold)

Gess, Friedrich W., Pulawski, Wojciech J. & Gess, Sarah K., 2015, A Revision of the rhopalocerus Species Group of Bembecinus Costa (Hymenoptera: Crabronidae: Bembicinae), Proceedings of the California Academy of Sciences 62 (7), pp. 207-256 : 238-240

Bembecinus rhopaloceroides (Arnold)

Figures 5b , 19 a-c.

Stizus rhopaloceroides Brauns, 1911:92 (sleeping on Datura ). Nomen nudum.

Stizus rhopaloceroides Arnold, 1929:294 , Figs 47 and 47a, ♀, ♂ (authorship attributed to Brauns). Syntypes: South Africa: Eastern Cape Province: Willowmore ( TMSA).— Arnold, 1930:20 (in checklist of Afrotropical Sphecidae ); Handcock, Chawanda, and Mhlanga, 1995: 40 (syntypes in NMZB].— As Bembecinus rhopaloceroides (Arnold) : Evans, 1966:135 (new combination, observations by Brauns, 1911); R. Bohart and Menke, 1976:532 (in checklist of world Sphecidae ); S. Gess, 1996:273 (floral records); S. Gess and F. Gess, 2003:117 (floral records), 2006:14 (floral records); Pulawski, 2014:33 (in catalog of world Sphecidae sensu lato).

RECOGNITION. — The female of B. rhopaloceroides shares with gariepensis the ferruginous terga (at least terga I and II) with pale yellow apical fasciae. Bembecinus inexspectatus and omaruru share this color pattern, but in inexspectatus the length of hindtarsal arolium is about 0.5 × of the inner claw, whereas about 0.25–0.30 × in rhopaloceroides and gariepensis ; in omaruru the setae of tergum II are erect at least laterally, where as they are appressed in the females of the other two species. Some karasanus are also similar, but in that species the labrum punctures are larger than those on the scutum, where as markedly smaller in the other two species.

The females of gariepensis and rhopaloceroides are identical morphologically and can only be identified by association with the topotypical males. The geographic distribution is of some help: rhopaloceroides occurs in the Eastern, Western, and Northern Cape Provinces of South Africa as well as in southern Namibia, whereas gariepensis is found in the Northern Cape Province of South Africa as well as in southern Namibia (in other words, gariepensis is unknown from the Eastern and Western Cape Provinces).

The male of rhopaloceroides shares with gariepensis an incrassate foretibia, with the dorsal margin convex in profile ( Fig. 19c , 7a). They differ as follows: in gariepensis , the foretibial inner surface is flat or nearly so, without emargination in the dorsal view ( Fig. 7b ); in rhopaloceroides , it has an oblique impression that in the dorsal view looks like an emargination at the tibia’s basal third ( Fig. 19b ).

VARIATION.— In most of the specimens examined, terga II and III are ferruginous or with insignificantly narrow black fascia basally and the pale yellow apical fascia not broadened laterally, in some females with a pair of black spots in the middle. The specimens from Aus, Namibia, have the pale yellow apical fasciae of terga broadened laterally; in the female, tergum II has a conspicuous black basal fascia and tergum III has only a minimum of ferruginous (anterior to the pale yellow apical fascia).

In most males, the gaster is all or largely ferrugineus (except for the yellow apical fasciae), but all black (except for the apical fasciae) in some specimens; some intermediate specimens have a small amount of ferruginous color on tergum I, just anterior to the yellow apical band.

In the vast majority of specimens, the setae are appressed on tergum II, but they are erect laterally in the single male from Aus, Namibia, up to 0.5 × midocellar width.

MATERIAL EXAMINED.— NAMIBIA: Aus , xii.1929, R.E. Turner (1 ♀, 1 ♂, BMNH) . SOUTH AFRICA: North West Province: Constable , xii.1962, SAM (1 ♀, SAMC) . Northern Cape Province: Namaqualand, Springbok, Hester Malan Reserve [now Goegap], 3–7.xi.1987, M. Struck (1 ♂, PPRI) ; Bloukrans near Calvinia, 17.xi.1931, J. Ogilvie (1 ♀, 2 ♂, BMNH); Pofadder , Bushmanland , Mus. Staff , x.1939 (1 ♀, SAMC) . Western Cape Province: Doringbos [NE of Clanwlliam], 3.xi.1966, J.G. Rozen (1 ♂, AMNH) ; Clanwilliam, F.W. Gess and S.K. Gess (2 ♂, AMGS) ; 43 km ENE Ceres on road to Sutherland , 2–3.xii.1989, R.W. Gess (1 ♀, 1 ♂, AMGS) , ♀ on flowers of mauve-white “mesem”, Mesembryanthemaceae ( Aizoaceae ); 18 miles [28.98 km] E Touws River to Hondewater , xii.1962, SAM [staff] (7 ♀, 123 ♂, SAMC) ; 18 miles [28.98 km] southeast Touwsrivier , 12.xi.1966, J.G. Rozen (3 ♂, AMNH) ; Koup at 33°07′S 21°17′E, 26.xii.1996, W.J. Pulawski (1 ♀, CAS) ; Koup Siding, Laingsburg , xi.1939, Museum Staff [ SAMC] (1 ♀, SAMC) ; Dikbome, Merweville, Koup , x.1952, Museum Expedition [ SAMC] (1 ♂, SAMC) ; Laingsburg at 33°12′S 20°51′E, 25 and 26.xii.1996, W.J. Pulawski (4 ♀, CAS) ; Oudtshoorn, Onverwacht , 9–12.xii.1986, F.W. and S.K. Gess (3 ♀, 1 ♂, AMGS) , 1 ♀ and 1 ♂ on flowers of Zygophyllum retrofractum Thunb. , Zygophyllaceae . Eastern Cape Province: Willowmore, no date, H. Brauns (2 ♀, SAMC ex NMZB; 1 ♂, UCDC), same locality, 20.i.1903, H. Brauns (1 ♀, SAMC) , same locality, 25.ix.1909, H. Brauns (1 ♂, SAMC) , same locality, 1.xii.1909, H. Brauns (1 ♂, SAMC) , same locality, 15.i.1910, H. Brauns (1 ♀, SAMC ex NMZB), same locality, 10.i.1912, H. Brauns (1 ♀, SAMC ex NMZB), same locality, ii.1914 (1 ♀, UCDC) , same locality, xi.1916, H. Brauns (1 ♀, 1 ♂, AMGS) , same locality, 1.xii.1917, H. Brauns (1 ♂, SAMC ex NMZB), same locality, xii.1920, H. Brauns (1 ♀, AMGS) , same data (1 ♀, SAMC ex NMZB), same locality, 12.i.1965, H. Empey (1 ♀, 1 ♂, AMGS) ; near Fullerton, C. Jacot-Guillarmod (3 ♂, AMGS) ; 4 miles [6.44 km] E Waterford, 29.x.1967, C. Jacot Guillarmod (1 ♀, AMGS) .

GEOGRAPHICAL DISTRIBUTION.— Known from southwestern Namibia, the Northern, Western and Eastern Cape Provinces of South Africa. It appears to have a southern distribution from the Succulent Karoo in the west to the Nama-Karoo in the east ( Fig.26b ).

FLORAL ASSOCIATIONS.— Visiting flowers of three plant families: Asteraceae ( Athanasia trifurcata (Linnaeus) Linnaeus ) (S. Gess and F. Gess 2003), Zygophyllaceae ( Zygophyllum retrofractum Thunb. ) and Aizoaceae (Mesembryanthema) (label data, see Material Examined; S. Gess and F. Gess 2003, 2006).

NESTING. — Unknown.

PREY.— Unknown.

Figures

FIGURE 5. Bembecinus spp.: a – quadristrigatus, female, male; b – rhopaloceroides, female, male; c – rhopalocerus, female, male; d – somalicus, female, male; e – zebratus, female, male (approximate lengths of females: a. 11.5 mm, b. 11.5 mm, c. 13 mm, d. 11.8 mm, f. 10.5 mm).

FIGURE 19. Bembecinus rhopaloceroides: a – api- cal hindtarsomere of female showing length of aroli- um, b – male foretibia in dorsal view, c – male foretib- ia in profile

FIGURE 7. Bembecinus gariepensis: a – male fore- tibia in profile, b – male foretibia dorsally.

FIGURE 26. Collecting records of Bembecinus spp.: a – quadristrigatus, b – rhopaloceroides, c – rhopalocerus, d – somalicus, e – zebratus, f – all species combined.