Karliella sexpunctata ( Karl, 1935 ) Michelsen, 2013

Michelsen, Verner, 2013, Proposal of Karliella gen. n. for the Afrotropical ‘ Pegomya’ sexpunctata Karl, 1935 (Diptera: Anthomyiidae), a possible kleptoparasite of dung-breeding beetles, African Invertebrates 54 (2), pp. 335-335 : 336-345

Karliella sexpunctata ( Karl, 1935) , comb. n.

Figs 1–21

Pegomyia sexpunctata: Karl 1935: 45 , fig. 3 ( South Africa, ♂ and ♀). Pegomyia abdominalis Emden, 1941: 263 ( Zambia, ♀). Synonymized by Pont and Ackland (1980: 718).

Description:

Size. Both sexes very variable, as indicated by a wing length range of 3.0– 5.5 mm.

Male.

Head ( Figs 1, 2 ): Ground colour dark on vertex, occiput and postgenae, light ochre-yellow on frons, parafacials and genae, covered in light grey to silvery grey dusting;

antennae brownish black or to varying extent orange-brown to orange-yellow on scape, pedicel and basal part of postpedicel; palpi brownish black, on basal half often ochre-yellow dorsally. Antennae distinctly shorter than comparatively deep face; plumose arista abruptly thickened basally; longest aristal rays ⅔ to fully as long as width of postpedicel. Proboscis short, with relatively slender haustellum and small labella; palpi slender, slightly longer than haustellum. Frons on upper part narrow, with contiguous parafrontalia, bare except for 2 or 3 pairs of frontals well below middle. Gena in profile 0.12–0.21× as deep as eye height, proportionately wider in large specimens; short genal setae arranged in single row but more abundant on aristal angle. Upper occiput without setulae below short postoculars.

Thorax ( Fig. 5 ): Ground colour wholly dark or to varying extent ochre-yellow on prothoracic parts, covered in thick light grey to olive-grey dusting, on middle third of mesonotum sometimes with a median brown vitta. Prosternum bare. Dorsocentral setae 2+3; acrostichals, except near scutellum, setulose, abundant and arranged in two close-set rows. Prealar seta about the same length as but weaker than posterior notopleural seta. Scutellum with minute hair-like setulae beneath tip. Proepisternals 2, proepimerals (1–)2. Anepisternum with anterodorsal seta; katepisternal setae 1–2+2. Anepimeron, katepimeron and metapleuron bare.

Wings ( Fig. 6 ): Wing and calypteres with a light brown tinge; haltere ochre-yellow. Vein C with short spinules in ad and av rows, bare on dorsal surface but with short setulae in two irregular rows ventrally. Lower calypter the same size as and thus distinctly projecting behind upper calypter in lateral view.

Legs: Ochre-yellow except for blackish tarsi, or sometimes (especially in small specimens) femora and hind tibia extensively brownish infuscated. Fore femur without a setae; fore tibia with a weak (sometimes absent) pv seta in middle, apically with d seta flanked by short ad and pd setae. Mid femur without av setae, but with 2 short pv setae near base; mid tibia with a small ad seta on distal third, 1 pd and 1 p setae on middle third. Hind femur has, in addition to sub-basal v seta, 3 or 4 short av setae on at least distal half and a few short pv setae on middle third and apically; hind tibia with 1–3 av, 2–4 ad, 1–4 (normally 2–3) pd setae, 0–1 p seta near middle, and an apical pv seta about the same length as sub-basal v seta on hind tarsomere 1.

Abdomen ( Figs 7–9 , 12–14 ): Slender, conical, subcylindrical, rather tapering, with small terminalia. Covered in thin silvery grey dusting over pale ochre-yellow ground colour except for paired brown to blackish rounded spots laterodorsally and ventrally at anterior margins of tergites III–V, sometimes even with indications of a median dark stripe on tergites II and III; caudal parts of abdomen often darkened to a varying extent, especially in small specimens. Robust hind marginal setae present laterally on tergites II and III and forming complete rows on tergites IV and V; discal setae absent. Tergite VI short, bare, incorporating spiracles VI near lateral margins; syntergosternite VII+VIII with pair of strong setae and some setulae. Sternite I setulose; sternites II–V at fore margin each with a widely spaced pair of alpha ­ sensilla; sternites III and IV with a pair of strong hind marginal setae. Sternite V small, cordiform, with short, sharply tapering posterior lobes.

Hypopygium ( Figs 15–18 ): Epandrium small, rather shallow, with a loose tuft of longish setulae at lower lateral sides; cercal plate on distal ⅔ forming an acutely pointed, beak-like process extending freely between surstyli and bearing three pairs of robust setae; a narrow, sclerotized bridge is formed between basal opposing parts of each cercus and surstylus; surstyli of unusual shape, split deeply into two slender arms; a narrow, sclerotized extension from epandrium unites with dorsobasal part of surstylus; bacilliform sclerites short, fused with ventrobasal extensions of surstyli; pregonites with two setulae, at outer basal margin articulated with central plate of hypandrium; postgonites slender and bare except for group of sensilla sub-basally; outer extension of phallapodeme detached from hind margin of hypandrial plate and from inner bases of pregonites; basiphallus with epiphallic extension and articulating with a short, sessile distiphallus without paraphallic processes or sclerotized acrophallus; ejaculatory apodeme notably small.

Female. Resembles male, except for the usual sexual differences.

Head ( Figs 3, 4 ): Frons rather narrow, less than 0.4× of total head width; frontal vitta markedly narrowing downwards: on upper part more than ⅓ of frontal width, above lunule much narrower than parafrontalia. Parafrontalia with (2–)3 orbital setae, 3(–4) frontal setae, without additional setulae; frontal vitta with pair of crossed interfrontal setae. Gena in profile 0.18–0.31× as deep as eye height, proportionately wider in large specimens.

Legs: Femora wholly ochre-yellow, with at the most tips of mid- and hind-femora narrowly infuscated. Fore tibia with larger pv seta and small ad seta on distal third. Mid tibial ad seta more robust. Hind femur with fewer (2–3) av setae confined to distal third, and only 2 pv setae, one near middle and one apically; hind tibia with fewer submedian setae: 1 av, 2–3 ad, 1–2 pd and 0 p.

Abdomen ( Figs 10, 11 , 19, 20 ): Sternite I bare. Sternites II–VII with paired alpha ­ sensilla at anterior margins. Oviscapt (6 th and following segments) very short, barely ⅓ as long as rest of abdomen, thick, moderately tapering. Spiracles VI situated within anterolateral margins of tergite VI; spiracles VII situated in membrane immediately behind lateral hind margins of tergite VI. Tergites VI and VII fully divided mid ­ dorsally, tergite VIII only with a posterior notch. Short cerci and hypoproct with dense cuticular pubescence, other sclerites of oviscapt only with dusting. Three spermathecae ( Fig. 21 ), smooth and globular, with a distinct neck.

Larvae and puparium. Unknown.

Egg. Creamy white, 1.1× 0.4 mm, in shape of a thick banana, being more tapered at the anterior (micropylar) end than posteriorly. Chorion throughout very finely porous (‘matt’), dorsally with two broad, parallel flanges running the length of the egg and delimiting a hatching pleat with coarse hexagonal ornamentation of raised ridges; chorion outside the flanges more or less longitudinally folded.

Type material: Pegomyia sexpunctata Karl, 1935 . Syntypes 3♂ 2♀ ( SDEI, examined by D.M. Ackland in 1975). SOUTH AFRICA: All specimens are labelled ‘ Montrose N.- Transv. Lingnau leg. 1926’ and ‘ Pegomyia sexpunctata Karl. ’. 1♂ also labelled ‘12.I.26’ and ‘ Pegomyia sexpunctata n. sp. / det. O. Karl. Stolp i Pom’, has been labelled as lectotype by D.M. Ackland, a designation presently effectuated. The remaining 2♂ 2♀ are paralectotypes and have been labelled accordingly by D.M. Ackland. 1♂ labelled ‘15.I.26’, and the other paralectotypes ‘12.I.26’.

Pegomyia abdominalis Emden, 1941 . Holotype ♀ and paratype ♀ (BMNH, examined). Mounted together on the same pin (larger lower specimen the holotype). ZAMBIA: Labelled ‘26.2.23. Loveridge/ Seemed to be oviposit-/ ing in dung ball of beetles. Mbala. 26/2/23’; ‘TANGANYIKA T./ A. Loveridge. ’; ‘ Pegomyia / abdominalis sp. n. / van Emden det. 1940’; ‘type the lower specimen’.

Other material examined (in BMSA, NMNW, ZMUC & BMNH): BOTSWANA: 1♂ 1♀ 29 km NE Kalkfontein, 12–13.iv.1972, Southern African Exp. , BMNH ; 1♀ Kuke Pan, 20°59'S 22°25'E, 14–15.iv.1972, Southern African Exp. , BMNH ; 1♂ L. Ngami, 19 km NE Sehithwa, 16–17.iv.1972, Southern African Exp. , BMNH. NAMIBIA: Bwabwata Park : 2♂ 8♀ Bum Hill campsite ( Kwando R.), 17°46'52"S 23°20'28"E, 10–13.ii.2004, A.H. Kirk-Spriggs, Malaise trap. Eenhana dist .: 1♂ 29 km E Okongo, 17°37'22"S 17°28'44"E, 14–15.x.1999, A.H. Kirk-Spriggs, T. Pape & W. Hauwanga, Malaise trap, dry woodland. Etosha National Park : 1♂ 2 km E Renostervlei , 19°09'59"S 14°33'12"E, 26–27.xii.1998, E. Marais, D.J. Mann & D. Newman, Malaise trap. Gobabis dist .: 2♂ 22♀ De Hoek , 21°56'26"S 20°58'55"E, 3–6.ii.2001, A.H. Kirk­Spriggs & E. Marais, Malaise trap ; 17♂ 40♀ Somerkoms , 22°01'59"S 19°57'22"E, 6–8.ii.2001, A.H. Kirk­Spriggs & E. Marais, Malaise trap. Grootfontein dist .: 1♀ Toggenburg campsite, 19°28'32"S 17°58'04"E, 18–20. ii.2004, A.H. Kirk-Spriggs, Malaise trap. Karibib dist .: 4♂ Ameib Farm, 31 km NW Karibib, 31.i–2.ii.1972, Southern African Exp. , BMNH. Katima Mulilo dist .: 3♂ 1♀ Salambala camp site, 17°50'01"S 24°36'09"E, 22–24.ii.2001, A.H. Kirk-Spriggs & E. Marais, Malaise trap, 8–10.ii.2004, A.H. Kirk-Spriggs, Malaise trap ; 47♂ 17♀ Salambala forest , 17°50'02"S 24°36'20"E, 23–29.xii.2002, A.H. & M.K. Kirk­Spriggs, Malaise trap ; 1♀ Salambala pan, 17°50'00"S 24°35'58"E, 1–4.iii.2001, A.H. Kirk­Spriggs, Malaise trap ; 4♂ Kubunyana camp, Kwando River , 17°87'S 23°33'E, 28–30.x.2003, A.H. & M.K. Kirk­Spriggs, Malaise trap ; 5♂ 10♀ near Mutonga village , 17°43.747'S 24°32.384'E, 930 m, 20–23.ii.2012, A.H. Kirk­Spriggs ; 1♀ Hippo Lodge , Zambezi R., 17°29'45"S 24°20'03"E, 6–7.ii.2004, A.H. Kirk­Spriggs, Malaise trap. Kaudom Game Park : 9♀ 10 km W of Dussi , 18°48'32"S 20°43'57"E, 29–30.xii.1998, E. Marais, A.H. Kirk­Spriggs & D.J. Mann, Malaise trap. Mukwe dist .: 5♀ Dijuvo, Okavango River , 18°04'04"S 21°28'51"E, 1.i.1999, A.H. Kirk­Spriggs, E. Marais & D.J. Mann, Malaise traps and sweeping ; 2♂ 4♀ Popa Falls Restcamp , 18°07'17"S 21°34'59"E, 13–16.ii.2004, A.H. Kirk­Spriggs, Malaise trap, riverine forest. Okahandja distr .: 2♂ 1♀ Okahandja , 2–4.ii.1972, Southern African Exp. , BMNH. Omaruru dist .: 1♀ Weissenfels , 21°04'S 15°59'E, 11.ii.1986, J. Irish. Otjinene dist .: 1♂ 9♀ 3 km N Epikuro River, 21°22'26"S 20°06'09"E, 9–11. ii.2001, A.H. Kirk-Spriggs & E. Marais, Malaise trap. Otavi dist .: 3♀ 29 km SW Otavi, 6.iv.1972, Southern African Exp. , BMNH. Otjiwarongo dist .: 1♀ Abachaus , xii.1951, G. Hobohm. Rundu dist .: 22♂ 80♀ Simanya, Okavango River , 17°33'17"S 18°32'30"E, 23–24.i.1998, A.H. Kirk­Spriggs & E. Marais, Malaise trap, riverine forest ; 1♀ Katara, Okavango River , 17°48'56"S 18°53'38"E, 20–23.i.1998, A.H. Kirk­Spriggs & E. Marais, Malaise trap ; 4♂ 5♀ 1 km S of Katara , 17°50'25"S 18°54'26"E, 22–23.i.1998, A.H. Kirk­Spriggs & E. Marais, Malaise trap, primary forest ; 1♂ 3♀ Hamoye National Forest , 18°12'S 19°43'E, 5–8.iii.1999, E. Marais, Malaise trap ; 1♀ Mile 46, 18°18'39"S 19°15'29"E, 25–27.iii.2003, A.H. Kirk­Spriggs, Malaise trap. Steinhausen dist .: 1♀ 24 km N Witvlei , 22°16'S 18°26'E, 18.iii.1984, J.G.H. Londt & B. Stuckenberg, acacia thornveld & grassy verge of road. Tsumkwe dist .: 5♀ Nama , 19°54'34"S 20°44'08"E, 20–22.xii.1998, A.H. Kirk­Spriggs, E. Marais & D.J. Mann, Malaise trap ; 1♀ 3 km N of Kano Vlei , 19°17'15"S 20°21'03"E, 19.xii.1998, A.H. Kirk­Spriggs, E. Marais & D.J. Mann, at light, dry woodland ; 1♀ Aha Hills , 19°47'36"S 20°59'51"E, 21–25.xii.1998,A.H. Kirk­Spriggs, E. Marais & D.J. Mann, Malaise trap ; 1♀ 2 km W Xawasha pan, 19°09'57"S 20°52'55"E, 26–27.xii.1998, A.H. Kirk­Spriggs & D.J. Mann, Malaise trap ; 1♂ Homasi , 19°40'39"S 20°37'08"E, 24.xii.1998, A.H. Kirk­Spriggs, E. Marais & D.J. Mann, ex fallen Baobab tree branch. West Caprivi Park : 1♀ Kwando River, Susuwe , 17°45'37"S 23°20'55"E, 28.ix–2.x.1998,A.H. Kirk­Spriggs, Malaise trap, dry woodland ; 8♂ 18♀ 5 km N Nova , 18°09'56"S 21°44'31"E, 16–18.xii.1999, E. Marais, D.J. Mann & D. Newman, Malaise trap, MV / UV light ; 9♀ 4 km W Immelman air strip, 17°46'36"S 24°16'30"E, 14.xii.1999, E. Marais, D.J. Mann & D. Newman, UV / MV light. SOUTH AFRICA: KwaZulu­Natal : 1♂ 2♀ Mkuzi Game Reserve, main camp park area, 25°35'S 32°13'E, 100 m, 1.ii.1988, J.G.H. Londt; Ndumo Game Reserve , camp & riverine bush , 1♂ 4–9.x.1982, J.G.H. Londt; 6♂ 22♀ Ndumo Game Rreserve , main camp area, 26°54.652'S 32°19.719'E, 27–30.xi.2009, A.H. Kirk­Spriggs, Malaise traps, broad ­ leafed deciduous woodland ; 1♂ 19♀ Ndumo Game Reserve, Shokwe area , 26°52.125'S 32°13.731'E, 30.xi–4.xii.2009, A.H. Kirk-Spriggs, Malaise traps, broad ­ leafed deciduous woodland ; 21♂ 66♀ Ndumo Game Reserve , main road, 26°54.288'S 32°17.974'E, 4–8.xii.2009, A.H. Kirk­Spriggs, Malaise traps, sand & broad ­ leafed deciduous forest ; 1♂ 4♀ Ndumo Game Reserve , pan, 26°54.288'S 32°17.974'E, 9–10.xii.2009, A.H. Kirk­Spriggs, Malaise traps, grassy floodplain. Mpumalanga : 1♀ Kruger National Park, Skukuza , 23.iii.1952,A.J. T. Janse & L. Vari ; 1♂ same locality, 23.xi.1959, F. Zumpt ; 1♂ Machadodorp , ii.1969, F. Zumpt .

Distribution: Apparently endemic to the southern part of the African continent, where it has so far been found in South Africa, Namibia, Botswana and Zambia.

Biology: Dissection of a large gravid female revealed 55 eggs, about one-third of them fully developed. There was no sign of a developing larva in a mature egg that was projecting from the vaginal opening, which indicates that Karliella sexpunctata is an obligate oviparous species.

The larvae are probably coprophagous, as judged by a published observation of a female apparently laying eggs on a scarab dung ball ( Emden 1941). Dung from herbivorous mammals dessicates quickly in warm and dry climates.Accordingly, some Diptera have evolved the habit of making their offspring feed on dung buried by scarab beetles (see Sivinski et al. 1999, and references therein), despite the obvious challenge of sharing this resource with the beetle offspring. It is of course too early to say whether this kleptoparasitic behaviour on the part of Karliella sexpunctata is obligate or facultative. Whatever the case may be, the pronounced variation observed in adult body size suggests that the larvae sometimes face serious limitations in food supply.

Figures

Figs 1–4. Karliella sexpunctata (Karl):(1, 2) male head, lateral and dorsal views; (3, 4) female head, dorsal and lateral views. Scale bar = 0.5 mm.

Figs 5, 6. Karliella sexpunctata (Karl): (5) male thorax, dorsal view; (6) male wing, ventral view. Scale bars: Fig. 5 = 0.5 mm, Fig. 6 = 1.0 mm.

Figs 7–9. Karliella sexpunctata (Karl), male abdomen, dorsal (7), ventral (8) and lateral (9) views. Scale bar = 0.5 mm.

Figs 10, 11. Karliella sexpunctata (Karl), female abdomen, dorsal and ventral views. Scale bar = 0.5 mm.

Figs 12–14. Karliella sexpunctata (Karl): (12) male sternites III–V and pregenital segments VI–VIII; (13, 14) male sternite V and pregenital segments VI–VIII, right and left lateral views. Scale bars = 0.25 mm.

Figs 15–18. Karliella sexpunctata (Karl): (15, 16) hypopygium, posterior and ventral views; (17) pre- and postgonite, lateral view; (18) phallus and ejaculatory apodeme, anterolateral view. Scale bars: Figs 15, 16 = 0.25 mm, Figs 17, 18 = 0.1 mm.

Figs 19–21. Karliella sexpunctata (Karl): (19, 20) oviscapt, dorsal and ventral views; (21) spermathecae. Scale bars: Figs 19, 20 = 0.25 mm, Fig. 21 = 0.1 mm.