Bembecinus quadristrigatus 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 : 236-238

Bembecinus quadristrigatus Arnold

Figures 5a , 18a-d.

Stizus quadristrigatus Arnold, 1929:297 , Figs 49 and 49a, ♀. Holotype: ♀, Namibia: Kunene Region Kamanyab [= Kamanjab] ( SAMC), photographs examined by W. Pulawski.— Arnold, 1930:20 (in checklist of Afrotropical Sphecidae ).— As Bembecinus quadristrigatus (Arnold) : R. Bohart and Menke, 1976:532 (new combination, in checklist of world Sphecidae ); S. Gess and F. Gess, 2003:117 (floral records); Pulawski, 2014:29 (in catalog of world Sphecidae sensu lato).

RECOGNITION.— Bembecinus quadristrigatus has the terga yellow with black, but without ferruginous. It has the scutum with a pair of admedian yellow stripes extending through most of scutum length, and the interocellar area yellow between midocellus and hindocellus. Unlike gilvus , the lower gena of quadristrigatus has a row of erect setae along the hypostomal carina and the lower metapleuron is microareolate (rather than closely, microscopically punctate). In the female, the labrum is unsculptured between the punctures, at least along midline (microscopically reticulate between the punctures in gilvus ), and the forebasitarsus is broader than in that species (compare Figs18a and 8a).

VARIATION. — Bembecinus quadristrigatus has two color forms, apparently identical morphologically, both of which occur in Namibia, and one in Angola and South Africa. In the first (including the type of quadristrigatus ), the metapleuron is all black, and tergum II has a median, subrectangular black mark that is rather well differentiated from the black, basal fascia and that extends beyond the tergal midlength. This form occurs in Namibia, in the Okahandja, Omaruru, Otjiwarongo, and Outjo areas. In the second form, known from Namibia, from the Aus, Karibib, Khorixas, and Usakos areas, and also from the Northern Cape Province of South Africa and from Angola, the metapleuron is all (most specimens) or partly yellow, and the black area on tergum II is (most specimens) reduced to a narrow, basalfascia, or the fascia is semicircularly broadened, also extending beyond the tergal midlength.

MATERIAL EXAMINED.— NAMIBIA (typical form): Kunene Region: Kamanjab ( Arnold, 1929); Khorixas , 4.iii.1990, W.J. Pulawski (1 ♀, CAS); 38 km W Khorixas, 4.iii.1990, W.J. Pulawski (1 ♀, CAS) ; Erongo Region: Omaruru/

Usakos at 21°41′S 15°59′E, 26.iv.2002, F.W. and

S.K. Gess (1 ♀, AMGS); 30k S Omaruru on road to

Karibib , 21°41′S 15°59′E, 24.iii.1997, F.W. and

S.K. Gess (4 ♂, AMGS), visiting deep pink flowers

of Hermbstaedtia odorata (Burch.) T. Cooke , Acan-

thaceae. ANGOLA (yellow form): Pedive ca 36 mi. E

Porto Alexandre, 24–27.vi. 1954, J. Balfour-Browne

(8 ♀, BMNH). NAMIBIA (yellow form): Otjozond-

jupa Region: Leeu River 9 km W Okahandja at

21°58′S 16°50′E, 13.ii.1996, W.J. Pulawski (1 ♀,

1 ♂, CAS); 70 km N Okahandja 16.iii.1990 , W.J.

Pulawski (1 ♀, CAS); Otjiwarongo , 1.i.1975 ,

Empey (1 ♂, AMGS); 44 km SW Otjiwarongo at

20°37′S 16°22′E, 4.iii.1996, W.J. Pulawski (1 ♀,

CAS); 3 km NE Kalkfeld, 2.iii.1990, W.J. Pulawski

(1 ♀, CAS); 25 km NE Kalkfeld at 20°41′S

16°18′E, 27.ii.1996, W.J. Pulawski (2 ♀, CAS) .

Erongo Region: western end of Grootberg Pass at

19°47′S 14°17′E, 19.iii.2004, F.W. and S.K. Gess

(1 ♂, AMGS), visiting flowers of Emelia mario-

thina (O. Hoffm.) C. Jeffrey, Asteraceae ; 7 km N

Palmwag at 19°51′S 13°54′E 26.iii.2004. F.W. and

S.K. Gess (1 ♀, AMGS); near Two Palms, Uniab

River at 19°53′S 13°54′E, 27.iii.2004, F.W. and S.K.

Gess (1 ♀, AMGS), visiting flowers of Zygophyllum

simplex L., Zygophyllaceae ; 120 km from Khorixas

on road to Palm at 20°17′S 14°05′E, 8.iv.1998, F.W.

and S.K. Gess (2 ♀, 1 ♂, AMGS); 5 km N Khorixas

Rest Camp at 20°20′S 14°55′E, 17.iii.2004, F.W.

and S.K. Gess (1 ♀, AMGS), visiting flowers of

Sesamum , Pedaliaceae ; 15 km from Khorixas on

road to Palm at 20°26′S 14°54′E, 1.iv.1997, F.W.

and S.K. Gess (1 ♀, AMGS); D2344 WNW Omat-

jete at 20°57′S 15°14′E, 15.iii.2004, F.W. and S.K.

Gess (1 ♂, AMGS); Uis to Omaruru at 21°14′S

15°00′E, 14.iii.2004, F.W. and S.K. Gess (2 ♂,

AMGS), one visiting flowers of Heliotropium tubu-

losum E. Mey ex Benth, Boraginaceae ; 6 km

N Omaruru at 21°27′S 15°59′E, 22.ii.1996, W.J.

Pulawski (1 ♀, CAS); 23 km N Karibib , 27.ii.1990 ,

W.J. Pulawski (2 ♀, CAS); 15 km W of Karibib ,

26.ii.1990, W.J. Pulawski (6 ♀, 5 ♂, CAS); same

data but 28.ii.1990 (4 ♀, 4 ♂, CAS); Uis/Henties

Bay at 21°27′S 14°45′E, 17.iv.2002, F.W. and S.K. FIGURE 18. Bembecinus quadristrigatus : a – Gess (1 ♀, AMGS), visiting flowers of female foretarsomere I, b – tergum I of typical form, Acanthaceae ; Omaruru/Usakos at 21°41′S 15°59′E, c – tergum I of yellow form, d – male tergum VII. 26.iv2002, F.W. and S.K. Gess (1 ♀, 1 ♂, AMGS), visiting flowers of Hermbstaedtia odorata (Burch.) T. Cooke , Amaranthaceae ; Karibib/Omaruru at 21°51′S 15°55′E, 12.iii.2004, F.W. and S.K. Gess (5 ♀, 1 ♂, AMGS); 15 km W Karibib at 21°56′S 15°42′E, 5.iv.1998, F.W. and S.K. Gess (11 ♀, 2 ♂, AMGS), visiting white flowers; 8 km W Usakos at 21°59′S 15°31′E, 15 Feb 1996, W.J. Pulawski (2 ♀, CAS); 117 km from Swakopmund on road to Usakos at 22°02′S 15°17′E, 16.iii.2000, F.W. and S.K. Gess (1 ♀, AMGS); 34 km SW Usakos at 22°02′S 15°17′E, F.W. and S.K. Gess (17 ♀, AMGS), visiting flowers of Petalidium lanatum (Engl.) C.B.Cl. , Acanthaceae ; between Kuiseb and Gaub passes, F.W. and S.K. Gess, at 23°24′S 15°50′E, 22.iii.1999 (1 ♀, AMGS) and 23°27′S 15°46′E, 22.iii.1999 (1 ♀, AMGS); 1–5 km E Usakos at 21°58′S 15°36′E, 14.iii.2014, J. Halada (2 ♀, 3 ♂, OÖLM); 25 km NEE Usakos at 21°52′S 15°19′E, 17.iii.2014, J. Halada (1 ♂, OÖLM); 5 km N Gobabeb, 26.ii.1979, Wharton (1 ♀, PPRI).! Karas Region: Aus, xii.1929, R.E. Turner (1 ♀, 1 ♂, BMNH); Onze Rust at 24°09′S 18°02′E, 17–18.v.1973, C. Jacot-Guillarmod (1 ♀, AMGS); Nomtsas Farm at 24°25′S 16°51′E, 18.iii.1997, F.W. and S.K. Gess (1 ♀, AMGS), visiting flowers of Sesuvium sesuvioides (Fenzl) Verdc , Aizoaceae ; Nomtsas at 24°25′S 16°51′E, 18.iii.1997, F.W. and S.K. Gess (1 ♂, AMGS), visiting flowers of Limeum argute-carinatum Wawra and Peyr , Aizoaceae 5 km S Mariental at 24°40′S 17°57′E, 31.iii.2000, F.W. and S.K. Gess (1 ♀, AMGS); SW Gibeon 41 km on 1089 at 25°20′S 17°29′E, F.W. and S.K. Gess, 8.iii.1999 (1 ♂, AMGS), 10.iii.1999 (1 ♀, 13 ♂, AMGS), visiting flowers of Limeum sp. , Molluginaceae , and 24.iii.1999 (1 ♀, AMGS). SOUTH AFRICA (yellow form): Northern Cape Province: Kalahari Gemsbok National Park, Nossob River bed 11 km NNE Twee Rivieren, 8–11.iii.1990, F.W. and S.K. Gess (5 ♂, AMGS), visiting flowers of Limeum aethiopicum Burm. , Aizoaceae ; Twee Rivieren in Kalahari Gemsbok National Park at 26°28′S 20°37′E, 30.x. 1990, M.W. Mansell (1 ♂, PPRI); 123 km N on road 360 from Upington to Kgalagadi at 27°30′S 20°48′E, 6.iv.2000, F.W. and S.K. Gess (1 ♀, AMGS): 61 km N on road 360 from Upington to Kgalagadi at 27°58′S 20°59′E, 6.iv.2000, F.W. and S.K. Gess (1 ♀, AMGS).

GEOGRAPHICAL DISTRIBUTION.— Known from the Nama Karoo from southern Angola, Namibia and the southern Kalahari in South Africa, and in northern Namibia penetrating the Namib Desert via the drainage channels ( Fig. 26a ).

FLORAL ASSOCIATION.— Visiting flowers of seven families: Acanthaceae ( Petalidium lanatum (Engl.) C.B.Cl. ), Aizoaceae (non-Mesembryanthema, Sesuvium sesuvioides (Fenzl) Verdc ), Amaranthaceae ( Hermbstaedtia odorata (Burch.) T. Cooke , Asteraceae ( Emelia mariothina (O. Hoffm.) C. Jeffrey ), Boraginaceae ( Heliotropium tubulosum E. Mey ex Benth. ), Molluginaceae ( Limeum aethiopicum Burm. and Limeum argute-carinatum Wawra and Peyr ), and Pedaliaceae ( Sesamum ) (label data, see Material Examined; S. Gess and F. Gess 2003).

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