Philodicus swynnertoni Hobby, 1933

Londt, Jason G. H., 2015, A review of the genus Philodicus Loew, 1848 in southern Africa (Diptera: Asilidae), African Invertebrates 56 (3), pp. 747-747 : 761

Philodicus swynnertoni Hobby, 1933

Figs 6 , 17–20

Philodicus swynnertoni Hobby, 1933: 109 (pl. II, fig. 2 ♂ gen., 3 ♀ ovipositor); Blasdale 1957: 144 (pl. I. fig. 13 ♂ gen., pl. II. fig. 6 ♀ S8); Hull 1962: 456; Londt 1978: 423 (figs 6 ♂ gen., 12 aed.); Oldroyd 1980: 343 (catalogue); Tomasovic 2012: 26.

A fairly large and distinctive species described by Hobby (1933) ‘from material preserved in the Hope Department, University Museum, Oxford. All were obtained during 1911 and 1912 by Mr. C. F. M. Swynnerton, at about 3 800ft., on Mt. Chirinda [c. 20°24'S 32°40'E 950 m], S.E. Rhodesia [ Zimbabwe]’. There were no fewer than 117 specimens in the type series (♂ holotype, ♀ allotype, 60♂ 55♀ paratypes) collected from December 1911 through to March 1912.

Material examined: SOUTH AFRICA: 1♂ ‘ Nelspruit [c. 25°29'S 30°58'E 735 m] / 2.1915 / A. Roberts’ ( NMSA)*; 4♂ 1♀ ‘ Sth Africa Transvaal / Cycad Trail / Dist Middelburg [c. 25°46'S 29°28'E 1525 m] / R. Elferink 5.i.1983 ’ ( NMSA); 1♀ same data but 3.i.1983 ( NMSA); 1♀ ‘ Irene [c. 25°53'S 28°14'E 1450 m] / M.G.A. Fourie / April 1969 ’ ( NMSA); 2♂ ‘JJO / JHB [= Johannesburg c. 26°10'S 27°58'E 1760 m] Tvl / 16.ii.1953 ’ ( NMSA); 1♀ ‘JHB [= Johannesburg c. 26°10'S 27°58'E 1760 m] No 2 / Glenwilliam [?] / 13/i/62 Muti’ ( NMSA); 1♂ ‘ Transvaal / Johannesburg [c. 26°10'S 27°58'E 1760 m] / Ross’ ‘SAM-DIP / A007826’ ( SAMC).

Material not studied: Londt (1978) lists unstudied type material ‘ Rhodesia: 1♂ holotype, 1♀ allotype, near Mt. Chirinda [c. 20°24'S 32°40'E 1010 m], 31.i.1912, C.F.M. Swynnerton (Oxford University Museum)’. Distribution, phenology and biology: While the type series was from Zimbabwe, Blasdale (1957) records the species from ‘ Sierra Leone, N. Gold Coast [ Ghana], S. Nigeria, S. Sudan, Uganda, Kenya, SE. Rhodesia [ Zimbabwe] (type locality), and Pretoria [in South Africa].’ Tomasovic (2012) added DR Congo to this list. The species therefore has a wide distribution which penetrates the north-eastern parts of southern Africa ( Fig. 6 ). Although habitat information is lacking the type series was almost certainly collected in montane grassland. Swynnerton collected the type specimens from December through to March. There is also a southern African record of the species collected in April ( Table 1 ). Tomasovic’s (2012) DR Congo records are for October and November so the species may have slightly different flight periods north of the sub-region covered by this study. While there are no prey records available for South Africa, Hobby (1935) analysed no fewer than 117 records for Zimbabwe, where the species was apparently common. Hobby’s published data can be summarised as follows (orders and families in alphabetical order) – Coleoptera (5): Cerambycidae (4), Curculionidae (1). Diptera (20): Asilidae (10), Bombyliidae (7), Syrphidae (2), Tabanidae (1). Hemiptera (13): Cicadidae (7), Lygaeidae (4), Pentatomidae (1), Reduviidae (1). Hymenoptera (32): Andrenidae (1), Anthophoridae (9), Apidae (4 Apis mellifera ), Bembecidae (1), Braconidae (1), Ichneumonidae (2), Megachilidae (7), Mutilidae (1), Scoliidae (5), Sphecidae (1). Lepidoptera (1): Sesiidae (1). Mecoptera (1): Bittacidae (1). Orthoptera (45): Acrididae (45). Although the species appears to feed on a wide range of prey some 38 % were grasshoppers ( Acrididae ). The male versus female ratio is of interest as only 21 (26.5 %) of the asilid predators were male while 86 (73.5%) were female – a clear indication that far more females were found feeding. The female ovipositor is distally narrow and spike-like so may be adapted for thrusting eggs into soil.

Figures

Fig. 6. Southern African distribution of Philodicus cinerascens (Ricardo, 1900) (●) and P. swynnertoni Hobby 1933 (▲).

Figs 17–20. Philodicus swynnertoni Hobby 1933. (17–19. male terminalia: (17) lateral, (18) dorsal and (19) ventral views. (20) female distal end of S8.