Spialia colotes transvaaliae Trimen, 1889

Cock, Matthew J. W., 2016, Observations on the biology of Afrotropical Hesperiidae (Lepidoptera) with particular reference to Kenya. Part 10. Pyrginae, Carcharodini, Zootaxa 4173 (4), pp. 301-350 : 318-322

Spialia colotes transvaaliae Trimen, 1889

Spialia colotes and S. confusa Evans are the only members of the colotes group of Spialia in De Jong's (1978) classification. Three subspecies are recognised for S. colotes , two of which occur in Kenya . The nominate subspecies was described as Pyrgus colotes Druce, 1875 from Angola, and is restricted to that country (De Jong 1978), Pyrgus transvaaliae Trimen, 1889 was described from Transvaal , South Africa, and is found as far north as Uganda and upland Kenya, and S. colotes semiconfluens De Jong, 1978 was described from Bihendula, [near Shikh, northern] Somalia and occurs in Yemen, and Ethiopia south to the dry north-eastern, eastern and southeastern parts of Kenya and north-eastern Uganda (De Jong 1978). However, there seems to be an eco-climatic cline between the two subspecies as many intermediate specimens occur in eastern Kenya , such as Besil (on the road to Namanga), Kibwezi and Voi (De Jong 1978). For this reason, Larsen (1991) does not recognise semiconfluens.

Specimens of the transvaaliae ‘form’ are quite common from scattered localities in the highlands of central and western Kenya, the Chyulu Hills, Teita Hills, Shimba Hills and coast. Van Someren's (1939) record of S. confusa obscura Evans from the Chyulu Hills is referable to this subspecies (De Jong 1978). In its range, ssp. transvaaliae is found in forest clearings, along forest tracks and margins and in disturbed places where its food plant occurs (including the author’s garden in Nairobi).

In Kenya, the form semiconfluens predominates in the lower and dryer areas, particularly the area between Nairobi and the Coast (where it is perhaps the commonest Spialia sp.), but also extending North into dry areas, and probably into the north-east and north-west. This form inhabits more open bush and scrubland.

Adult behaviour. In forest S. colotes transvaaliae ( Figure 14 ) will flit about clearings, and the males defend a territory, often an isolated clump of the food plant. In dry scrub, S. colotes semiconfluens can be found in clearings and along open tracks, flying close to the ground when it is difficult to see and follow, although perching frequently but briefly.

Food plants. I have found caterpillars of this species repeatedly on Hibiscus fuscus ( Figure 15 ) in the Nairobi area , and on no other hosts. Doubtless in the drier parts of Kenya where H. fuscus is not found, other food plants are used. Larsen (1991) includes my food plant record, which is probably the origin of the listing of this species in Henning et al. (1997), Heath et al. (2002) and Woodhall (2005). Recently, Otto et al. (2013) record it from Hibiscus aethiopicus var. ovatus and Pavonia burchellii in the area of Kruger National Park , South Africa.

Ovum. Ova are laid on the terminal leaves of the lower side-shoots of H. fuscus , and not usually on the apical shoot. Two ova associated with newly hatched caterpillars (which were not reared) and older caterpillars (one of which was reared) of S. colotes on H. fuscus at North Muguga Forest ( MJWC 88 /23) were probably this species. Although S. spio also occurs uncommonly at this site, and has been reared from this food plant, the ovum illustrated by G.C. Clark (in Dickson & Kroon 1978) differs. They measured 0.77mm in diameter and 0.67mm in height (n=4); there were 19–20 irregularly interrupted and misaligned ridges around the perimeter of the ovum; in the basal part these were less prominent; around the widest part of the ovum comprised the longest sections of uninterrupted ridge, the next row above this was similar, but ridges were shorter and slightly fewer in number; the top row, around the micropyle, was damaged by the eclosing caterpillar but appears to have comprised significantly fewer ridges. The ridges were joined by about 20 low, narrow, transverse ridges. The eclosing caterpillar ate a hole at the top of the ovum but did not eat the eggshell.

Leaf shelters. On H. fuscus , the caterpillars make a shelter by folding up a leaf along the mid-rib. The youngest caterpillars make shelters with the youngest leaves which are already folded along the mid-rib before opening, and feed on the leaf upper surface without perforating it. Older caterpillars use larger leaves, and feed on the distal portion.

Caterpillar. There appears to be five instars, but the head capsule dimensions are variable in the later instars. The dimensions for my material are as follows (in mm, wide x high): instar 1, 0.46 x 0.48 (n=1); instar 2, 0.67 x 0.66 (range 0.64–0.70 x 0.62–0.70, n=2); instar 3, 1.06 x 1.14 (range 0.94–1.10 x 0.96–1.20, n=5); instar 4, 1.44 x 1.52 (range 1.25–1.57 x 1.25–1.65, n=8); instar 5, 1.98 x 2.07 (range 1.73–2.20 x 1.76–2.35, n=6).

Instar 5 ( Figure 16 ). Head rounded, slightly and broadly indent at vertex; shiny black, rugose; short, pale, erect, aciculate setae across face, apart from along epicranial suture, and less so along adfrontal suture, and bare round patches on upper epicranium and below this adjacent to adfrontals, giving a double eye-spot appearance; scattered longer, pale, erect, simple setae amongst these, as well as above and on labrum, and ventrolaterally; similar but dark setae dorsally; a few very long, robust, erect but curved forwards apically, slightly barbed setae dorsally, laterally and on lower edge of upper epicranial dark spot. The dark spots on the epicranium are sometimes obscured by a more extensive cover of pale setae, especially the lower spot. T1 black with pale or pale brown rectangles dorsally and dorsolaterally in anterior two-thirds; in some cases there is a narrow white dorsal line in posterior third; mixed long and very long pale, erect, simple setae on anterior half. Body green, posterior half may be more yellow in tone; dorsal line darker; several diffuse and indistinct dorsolateral and lateral lines; sparsely covered with short, pale, erect, pale setae; longer ones mostly blunt or slightly clubbed; a few scattered longer pale, simple setae. T1 legs dark brown or black, but may be light brown; T2–T3 legs light brown. The final instar lasts 17–22 days.

Instar 4 ( Figure 17 ). Shape of head similar to last instar; generally shiny black, and reticulate-rugose; labrum brown; short, pale, aciculate, semi-recumbent setae across face; scattered longer, erect, blunt, dark setae throughout, which may be paler on the face ventrally; small numbers of even longer (0.4mm), robust black setae, erect but flexible, some slightly spatulate; posterior margin free of setae. Occasionally traces of the epicranial dark spots as in the final instar are apparent. T1 black with a white dorsal line, narrow posteriorly, and a broader white lateral line; legs dark. This instar lasts 9–13 days.

Instar 3. Head dark brown rather than black, labrum brown; shiny; reticulate sculpture; scattered white setae on face mostly short and often clubbed, but some longer; longer, pale erect, simple setae laterally, mixed with much longer (0.4mm) black barbed setae sparsely scattered.

Instar 2. Head smooth, shiny with weak, irregular ridges; almost black, labrum brown; long pale, erect, simple primary setae; scattering of short, falcate pale setae; T1 black, unmarked. Body pale green with short pale, erect setae; all legs concolorous with body.

Instar 1. Head smooth, shiny; dark brown, labrum brown; long, pale, erect, simple primary setae only.

Pupa. One field collected pupa was in a shelter made from a whole leaf with the edges rolled downwards to create a shelter, oval in cross section. Another was in a shelter made by drawing three leaves together. The pupa as shown in Figure 18 is 10–12mm long; it is covered with a white waxy bloom, and short, erect, curved, pale, simple setae; the proboscis sheath projects slightly beyond the end of the wing sheaths; spiracles dark, those of A 2 – A 3 sometimes partly visible from under the hind wing dorsum. The colouring of the pupae is variable and confounded by the internal colouring being partially visible through the cuticle. Based on the cuticle colouring of emerged pupae, at one extreme it is common for the whole pupa to be dark, blackish brown, and at the other extreme, sometimes the pupa is hardly marked at all. The pupa shown in Figure 18.1 is at the pale extreme, while that shown in Figure 18.2 is intermediate, with conspicuous white wings which will turn darker later and through which the adult wing pattern will be visible. The T 1 spiracle is brown to dark brown, oval, 0.47 x 0.58mm wide x high (range 0.40–0.52 x 0.56–0.64, n = 4), with a cauliflower-like texture; the surface is tipped at an angle, the posterior margin raised 0.27mm (range 0.24–0.30, n = 4) with a vertical wall in the lower half, which is smooth, fluted and usually paler brown; the upper part of the spiracle bulges over this wall. There are small oval, flat, slightly raised, shiny brown plaques on the abdomen surface : A 2 – A 7 subdorsally on anterior margin and A 4 – A 7 ventral and anterior to spiracles. In one individual ( MJWC 88 /33) there is an additional such structure on one side only just above the partially visible A 2 spiracle. One pupa ( MJWC 88 /42B) has the A 2 – A 7 subdorsal structures displaced to just dorsal and anterior to the spiracles, and this matches the pupa shown in Figure 18.1 (which unfortunately failed to emerge). Pupation takes 12–14 days.

Natural enemies. The caterpillars are quite commonly attacked by an ichneumonoid discussed under S. spio above, with records from Muguga and Nairobi.

Figures

FIGURE 14. Adults of Spialia colotes transvaaliae, Kenya. 1 – 2, male, collected as young caterpillar on Hibiscus fuscus, Nairobi, 6 May 1989; adult 24 Jun; MJWC 89 / 33 B. 3 – 4, courting pair, male on the right, Kibwezi, 17 Dec 1989.

FIGURE 15. Hibiscus fuscus, the normal food plant of Spialia colotes transvaaliae in the central highlands of Kenya. 1, Nairobi, Jul 1989. 2, Ngong Forest, Nairobi, 30 Oct 1988.

FIGURE 16. Final instar caterpillar of Spialia colotes transvaaliae, collected on Hibiscus fuscus, Nairobi, Kenya. 1, dorsolateral view; collected 15 Apr 1988; photographed 15 Apr; pupated 5 May; 11 mm; MJWC 88 / 33. 2, dorsal view; as # 1. 3, dorsal view; collected 25 Oct 1988; photographed 7 Nov; died; MJWC 88 / 101.

FIGURE 17. Penultimate instar caterpillar of Spialia colotes transvaaliae, collected as young caterpillar on Hibiscus fuscus, Karen, Nairobi, 29 Oct 1989; moulted to penultimate instar 19 Nov; photographed 20 Nov; moulted to final instar 28 Nov; 8 mm; died as pupa; MJWC 89 / 84. 1, dorsolateral view; 2, detail of head and feeding damage.

FIGURE 18. Pupae of Spialia colotes transvaaliae, lateral view. 1, collected as pupa on Hibiscus fuscus, Kadera God Forest, near Kisii, 5 Aug 1990; photographed 8 Aug; died; the dark spot towards apex forewing is a blemish; MJWC 90 / 82 A. 2, collected as young caterpillar on Hibiscus fuscus, Nairobi, 6 May 1989; pupated 4 Jun; photographed 14 Jun; died as pupa; MJWC 89 / 33 A.