Sarangesa phidyle ( Walker 1870 )

COCK, MATTHEW J. W. & CONGDON, T. COLIN E., 2011, Observations on the biology of Afrotropical Hesperiidae (Lepidoptera) principally from Kenya. Part 3. Pyrginae: Celaenorrhinini, Zootaxa 3033 (1), pp. 1-67 : 46-49

Sarangesa phidyle ( Walker 1870) ( Figures 46–49 )

This species is widespread in dry parts of Africa from Arabia, through north–eastern Africa and East Africa to South Africa, and west to Senegal and Gambia.

Evans (1937) divides S. phidyle into two forms: the wet season phidyle Walker , uniform brown above with well marked hyaline spots, and the dry season varia Evans 1937, variegated brown and olive green with insignificant hyaline spots. I have not been able to associate these colour variations with any particular season in Kenya, and have noted in the aggregations which can be found in termite mound chimneys that a wide range of colour and markings occur together. Specimens from the coast seem to have the largest hyaline markings and the most contrasting UPH.

S. phidyle is quite variable in colour, markings and size. The ground colour varies from a light whitish brown, through brown to olive-brown. My specimens with the most striking olive colouring were all reared so that I won- der if this is a character of fresh specimens which fades rapidly in the field. The hyaline markings vary from almost non-existent to quite strong (reminiscent of S. seineri ), and the UPH markings vary from only slightly contrasting to strongly contrasting. Size is moderately variable, with a tendency to produce small individuals, a trait also exhibited by S. lucidella (Mabille) .

This is one of the more common and widespread skippers of Kenya. Although not normally found in rain forest, it occurs in dry forests, bush and semi-desert over wide areas. Van Someren (1939) records it as numerous on the edges of the track through the mixed forest on the lava ridges of the Chyulu Hills, but distinctly scarce over 1,370 m (4,500 ft.). In Kibwezi Forest I found it only sporadically. The adult roosting behaviour described below makes this species easy to locate in dry scrub such as the Tsavo area .

Adult behaviour

In flight this species is usually distinctly orange, like S. motozi . It usually settles on the ground, where it blends in well on bare soil. When disturbed in open grazed forest it will often fly a short distance (10 m) and settle again on the soil. It's camouflage is so good that even if the precise spot it settled is seen it often cannot be located until it is disturbed and flies again – not too difficult to capture, but exasperating to photograph.

S. phidyle can be active into the late afternoon and dusk (e.g. at flowers, Meru Muliku at 18.30, 21 Aug 1987) .

It feeds at flowers when available including Bougainvillea (which in June 1990 was one of the few flowering species at Aruba Lodge), Acanthaceae (Bushwhackers) and dryland Apocynaceae (Meru Muliku). Late one afternoon at about 18.00, I observed a male defending a territory in Kibwezi Forest (15 May 1991). The territory was one of the last patches of sunlight along a path through the forest. The male sat on a perch at the patch and repeatedly flew up to chase off intruders, including other larger species such as Coeliades spp.

The adults of both sexes normally roost together in patches of shade provided by overhangs, animal burrows and the chimneys of termite mounds ( Figures 46.2 and 47 ). I have observed this behaviour at Kiboko (about 15 in one termite mound 24 Jun 1990; several at 19.00h on 25 Sep 1990, and again at 08.00h the next morning), near Bushwhackers (about 15 in small animal burrow, 12 Jun 1988), Tsavo East (in the heat of the day 3 out of 6 termite mounds each had about 20 adults in them, 24 Jun 1990), between Voi and Ndara Ranch (0, 2 and 7 in successive termite mounds between 18.20 and 18.30, 23 Jan 1991, and 2, 7 and 12 in the same mounds at about the same time the next day), Magadi Road (2 large animal burrows, each with about 20 adults at about 13.30h, 28 Sep 1991). This behaviour is not purely for protection from the heat of the sun, as S. phidyle can be found in termite mound chimneys early in the morning and in the evening, as well as during the heat of the day; they probably remain there at night as well. Here, I include part of a group from a mound near Voi ( Figure 46.2 ). At the time, I noted these as mounds of a Macrotermes sp. , but no longer recall the origin of this identification or why I applied it. Preston-Mafham & Preston-Mafham (1988, p.95) show a rather worn female (misidentified as S. lucidella ) showing this behaviour in the chimney of an Odontotermes lateriticus mound in the Masai Mara.

Food plants

Sevastopulo (unpublished) found a pupa in a shelter between two leaves of a Barleria sp. , which he concludes is probably a food plant. Clark (in Dickson & Kroon 1978, plate 7) illustrates the life history in detail and gives Peristrophe hensii as the food plant in southern Africa. Larsen (1991, 2005) and Heath et al. (2002) repeat these records, but Kielland (1990) gives only the South African record. It seems likely that several Acanthaceae are acceptable food plants, given the wide range of this species.

I first found the caterpillar of this species in a leaf fold on Amaranthus dubius (Amaranthaceae) at Kisumu (87/ 34). Although Amaranthaceae are occasionally hesperiid food plants in the Neotropics and Asia (see Introduction), I am not aware of any African species which feed on this family of plants. The Kisumu caterpillar pupated a couple of days later, and I conclude that A. dubius was only being used as a pupation site—as was reported on one occasion for Eagris sabadius astoria Holland on another Amaranthaceae , Achyranthes aspera ( Cock & Congdon 2011) .

Subsequently I found the food plant at Kibwezi Forest to be Monechma debile (Acanthaceae) (91/29). When I Leaf shelters

A mature caterpillar on Monechma debile formed a minimal shelter by rolling up the edges of one of the long, narrow leaves, and holding the edges together with a few strands of silk (91/29B). Another caterpillar used three leaves, the lower two edge to edge, and the upper one held convexly on top with silk strands (91/29A). Smaller caterpillars also use individual rolled leaves and one leaf on top of another. The smallest shelters are found on the youngest leaves, suggesting this is also where the ova are laid.

Ovum

I have not seen the ovum, but the one illustrated by Dickson & Kroon (1978) resembles that of S. haplopa and has 16 ribs, seven reaching the micropyle.

Caterpillar

There are five instars according to Clark (in Dickson & Kroon 1978), but I have not confirmed this in Kenya. The following observations in Kenya are compatible with Clark’s more detailed account. An n–3 (?second) instar caterpillar (90/29C) had a dark brown head, 0.74 x 0.69 mm wide x high; shiny, reticulate small ridges; pale setae, stellate on a short stalk, cover head apart from upper area of face. The n–2 instar caterpillar also had a dark head, 1.21 x 1.19 mm wide x high, with similar ridges and setae, and a plain reddish brown body (90/29C). The head of the penultimate instar caterpillar ( Figure 48.1 ) measured 1.83 x 1.83 mm wide x high (n=4) and is similar, while the body resembles that of the final instar. Final instar caterpillar ( Figure 48.2 ) 15 mm long (90/28). Head dark brown; quite deeply indented at vertex; shiny, covered with reticulated small ridges; 2.6 x 2.6 mm wide x high (n=5, 4); densely covered with scattered tufts of short pale hair-like setae, up to eight arising from a common base, some bifurcate just before apex (see Plate 7, Fig. 16 by Clark in Dickson & Kroon 1978). T1 as body; body yellow green with yellow-white dots, which are very short, pale, stalked, stellate setae; dorsal line darker; white dorsolat- Pupa

The pupa ( Figure 49 ) matches that shown by Clark (in Dickson & Kroon 1978) and is similar to those of S. motozi and S. haplopa below. The one obtained on Amaranthus dubius (87/34) was described. Length 15 mm, 4.5 mm at the widest; proboscis sheath stops short of the cremaster; green, abdomen with a brown tint; covered with a light particulate wax bloom; spiracles brown, that of T1 larger and conspicuous. Pupae took 12 days (11, 11, 12, 13, 14) to emerge.

Natural enemies

One mature caterpillar collected on M. debile at Kibwezi Forest in the final instar (90/28) was parasitized by an Apanteles (s.l.) sp., which formed its cocoons in a loose mass beside, and partially over, the host corpse. The sex ratio of the adults which emerged nine days later was strongly female biased: 1♂, 32♀ .

Dickson & Kroon (1978) record two tachinids, Pales coerulea (Jaennike) and Ctenophorocera sp. , from pupae of this skipper.

Figures

FIGURE 16. Male Celaenorrhinus sanjeensis, Kihansi Gorge, c. 600 m, Tanzania, 9 Oct 2006 (TCEC).

FIGURE 46. Adult Sarangesa phidyle. 1, near Voi, 23 Jan 1991. 2, near Voi, in chimney of Macrotermes sp. mound, 24 Jan 1991.

FIGURE 47. Macrotermes sp. termite mound, near Voi, Jul 1990.

FIGURE 48. Caterpillar of Sarangesa phidyle. 1, n–1 caterpillar, dorsal view; collected on Monechma debile, Kibwezi Forest, 8 Apr 1991; photographed 9 Apr 1991, 12 mm; moulted to final instar 11 Apr; 91/29A. 2, final instar caterpillar, detail of head, anterior view, collected on M. debile, Kibwezi Forest, 27 Mar 1990; photographed 27 Mar; parasitized by Apanteles (s.l.) sp. 8 Apr; 90/28.

FIGURE 49. Pupa of Sarangesa phidyle collected as n–1 caterpillar on Monechma debile, Kibwezi Forest, 8 Apr 1991; pupated 20 Apr; photographed 21 Apr 1991, 15 mm; emerged 1 May; 91/29B. 1, lateral view. 2, ventrolateral view.