Coeliades kenya Evans, 2010

Cock, Matthew J. W., 2010, Observations on the biology of Afro-tropical Hesperiidae (Lepidoptera) principally from Kenya. Part 1. Introduction and Coeliadinae, Zootaxa 2547, pp. 1-63 : 48-52

Coeliades kenya Evans stat. rev. ( Figures 42–48 )

Originally, Evans (1937) described this as a distinct species. Subsequently, he treated it as a subspecies of C. keithloa Wallengren , which he considered to have five subspecies found from Ethiopia to South Africa ( Evans 1947). Henning et al. (1997) treated all five subspecies as valid separate species. However, Chiba (2009) overlooked this treatment and separated the five subspecies of Evans into two species: C. keithloa with subspecies keithloa and lorenzo Evans restricted to South Africa and Mozambique, and C. menelik Ungemach from Ethiopia with two more subspecies from Kenya: merua Evans from Meru and kenya from the Kenya coast. In doing so, Chiba (2009) referred to my unpublished observations on the life history which supported this split between ssp. keithloa and ssp. kenya (which Sevastopulo (unpublished) has also pointed out).

Evans (1947) provides diagrams of the genitalia of the five taxa he treats as subspecies of keithloa , which are of better quality than those in Evans (1937). Chiba (2009) provides good illustrations of the male genitalia of keithloa, lorenzo, kenya and merua, but unfortunately does not include menelik or sejuncta . The last named seems close to menelik and merua, based on adult appearance and the genitalia diagrams in Evans (1937). Ungemach (1932) noted that the under side of C. menelik is closest to that of C. sejuncta , but the underside of merua is closer still. I have followed Henning et al.’s (1997) treatment of the two southern taxa, which have rather different caterpillars, as discussed below. The situation with regard to the three northern taxa is not so clear-cut, particularly without good illustrations of the male genitalia of menelik and sejuncta . However, the genitalia of merua and menelik are clearly similar, and so may well be subspecies, possibly of sejuncta , but the genitalia of kenya are sufficiently different that I think it must be treated as a valid species, as Evans (1937) originally suggested. I therefore leave merua as a subspecies of menelik , pending further study, but raise kenya to species level: Coeliades kenya stat. rev.

Coeliades kenya is restricted to the coast of Kenya, perhaps extending into Tanzania. I have found this species only at Diani Beach, Kenya, where the adults are occasionally seen ( Figure 42 ), but the caterpillars are quite easy to find.

Food plants

On the Kenya Coast this species is quite easy to find on Acridocarpus zanzibaricus ( Figure 43 ), which is the only food plant I have located. Sevastopulo (unpublished) gives the same food plant, while van Someren (1974) gives A. zanzibaricus , A. glaucescens , and Rourea orientalis (= Byrsocarpus orientalis ) ( Connaraceae ) for Coeliades keithloa “and subspecies”, which are likely to refer to C. kenya . Kielland (1990) gives A. zanzibaricus and A. glaucescens ; since he was not familiar with this species, he was presumably quoting other sources, perhaps referring to C. keithloa for the latter rather than C. kenya . I am not aware that the food plants of C. menelik menelik or C. menelik merua have been recorded.

Ovum

The ovum ( Figure 44 ) is red, hemispherical with a narrow flange around the base, 1.03 x 0.7mm wide x high, with 17–18 raised ribs; the area between the ribs filled by rows of parallel lines. Ova are laid on the young stem, the flower buds or the base of young leaves. When inflorescences and young shoots are available, they are used for oviposition, and heavy ovum loads have been observed. For example, on 12 Apr 1990 at Diani Beach (90/44G), one 15cm vegetative shoot with about 12 young leaves or side shoots had 25 ova, of which one was viable, 11 had hatched normally, and 13 were parasitized, of which ten had already emerged. On the same occasion, five flowers had a total of 14 ova, of which five had hatched normally, and the remaining nine had been parasitized, five of which had already emerged.

Leaf shelters

The fourth, and subsequent instar caterpillars make no shelter beyond pulling the leaf margins slightly together with one or two strands of silk ( Figure 45 , right), i.e. a type 1 no–cut shelter, similar to that described above for C. sejuncta on this food plant. Once a leaf with feeding damage and what may have been an early shelter was found ( Figure 45 , left), but this was not carefully observed or recorded at the time.

Caterpillar

Caterpillars were found on Acridocarpus zanzibaricus , both in the shade of Jadini Forest, and in more or less open scrub close to the beach. Ova, young and mature caterpillars could all be found on the same plant at the same time. When ova are laid on inflorescences, feeding by the first two or three instars is on the flowers. This feeding can cause very considerable damage to individual inflorescences.

It is not clear from my material how many instars there are in the development of C. kenya , or whether there is the same number of instars in each sex. The final instar female caterpillars are slightly larger than those of males: female head capsules measure 5.29 x 5.19mm wide by high (n=7), whereas males measure 5.06 x 4.87mm (n=6). Similarly the penultimate instar caterpillars (same individuals) also differ in size: female head capsules 3.61 x 3.57mm wide x high (n=2) compared to males 3.25 x 3.33mm (n=6). Although the head capsules of the first three instars are differentiated in size, from the fourth instar onwards, there is increasing variation and overlap between instars, which make it difficult to resolve the instars without rearing caterpillars through from the ovum or earliest instars, which I have not done. Hence, it is not clear whether female caterpillars are simply larger, or whether they go through an extra instar. My provisional interpretation is that there are at least six instars in both sexes, possibly seven, but that head capsule size is variable, related to sex and final caterpillar size.

Final instar ( Figure 46 ).The following description is based on individual 89/22A, which was collected at Diani Beach, 28 Mar 1989. The description was prepared 29 Mar, when the caterpillar measured 32mm; it grew to 40mm by 1 Apr, and pupated 10 Apr. The head capsule measured 5.1 x 4.7mm —the smallest of the seven female caterpillars that I measured.

Head plain chestnut brown; dark mark over stemmata; reticulated; shiny. Body widest at A1–2, 6 x 6mm wide x high. T1 black with slight orange band on posterior margin. T2 anterior half black with broad white dorsolateral transverse dash on anterior margin; posterior half orange to the base of the legs. T3–A7 as T2, but with a broad dorsolateral white transverse dash before anterior margin and another laterally at the level of the spiracles. A8 similar, but black is 2/3 of segment and orange 1/3. A9 black with an orange band from anterior margin laterally to mid-segment at dorsum; a broad white dorsolateral broad streak in anterior half. Two small white spots posterior to orange band. Ventrum dark reddish brown. True legs black; prolegs with basal portion black anteriorly and orange posteriorly, and distally dark reddish brown. Spiracles at the division between black and orange on each segment; black, inconspicuous.

Penultimate instar. Similar to final instar. Head 3.61 x 3.57mm wide x high (n=2) in female and 3.25 x 3.33mm (n=6) in male. A3–A6 with orange slightly more than posterior half of segment; orange bands are duller and slightly more yellow.

Instars 4 to penultimate. Similar to penultimate.

Instar 3. Head 0.96 x 0.93mm wide x high (n=1). Similar to instar 4, except: T1 orange band is continuous at dorsum; T2 no white spots; T3, A1, A8 no lateral white spots; A9 no white spots.

Instar 2. Pale brown head, 0.79 x 0.86mm wide x high (n=1); body banded in black and yellow. The yellow blends well with the flowers of A. zanzibaricus ( Figure 47 ).

Instar 1. Light orange-brown head, 0.6 x 0.5mm wide x high (n=2); body light orange-brown.

Pupa

In captivity, pupation always occurred on the lid of the rearing container ( Figure 48 ), or occasionally between a leaf and the lid. Hence, it seems likely that pupation is not in a leaf shelter on the food plant, but perhaps at ground level amongst dead leaves. The following description is based on male individual 89/22D which pupated 28 Apr 1989, was described 1 May and emerged 15 May.

Length 27mm; negligible white waxy bloom. Ground colour whitish orange brown; orange brown between segments of abdomen and delineating sutures on head and thorax. Frontal spike 1mm, distal half black. Black markings as follows: spot each side of base of frontal spike; spot anterior and adjacent to eye; row of three ventrally, posterior to the eyes, the central one small, the lateral ones large; three dots each on legs of T1 and T2; row of small dots distally on leg of T2;; margin F and termen H with black line; a triangular spot (may also be + shaped as in Figure 48 , right) at end cell F; a broad black streak in space 1 F; A5–6 transverse bars each side of ventrum; A2–A8 row of large spots laterally over the spiracles; scatter of about eight dots around base of wings and spiracle T1; elongate spot just dorsal to spiracle T1; narrow triangle on dorsum T2, base near posterior margin; cremaster outlined in black.

Natural enemies

The ova are parasitized by a solitary Hymenoptera parasitoid. Limited quantitative data (see under ovum) shows that on occasions more than 50% of ova are parasitized. No caterpillar or pupal parasitoids were reared.

Figures

FIGURE 42. Newly emerged male Coeliades kenya, collected as caterpillar on Acridocarpus zanzibaricus, Diani Beach, 28 Mar 1989, adult 15 May (89/22D).

Figure 43. Acridocarpus zanzibaricus, Diani Beach, 15 Dec 1989; food plant for Coeliades kenya, C. sejuncta and Pyrrhiades a. anchises.

FIGURE 44. Ovum of Coeliades kenya on Acridocarpus zanzibaricus, Diani Beach, 18 Apr 1990 (90/44G); left dorsolateral view; right, lateral view.

FIGURE 45. Leaf shelters of Coeliades kenya on Acridocarpus zanzibaricus, Diani Beach, 28 Mar 1989 (89/22); left, possible stage 2 shelter which contained an instar 3 or 4 caterpillar; right, minimal shelter of final instar caterpillar.

FIGURE 46. Final instar caterpillar of Coeliades kenya collected on Acridocarpus zanzibaricus, Diani Beach, 18 Apr 1990, moulted 7 Apr, photographed 8 Apr, 33mm (90/44B).

FIGURE 47. Instar 2 caterpillar pre-moult of Coeliades kenya on flower of Acridocarpus zanzibaricus, Diani Beach, 18 Apr 1990 (90/44E), 10mm.

FIGURE 48. Pupae of Coeliades kenya, collected as caterpillars on Acridocarpus zanzibaricus, Diani Beach; left, dorsal view, collected 28 Mar 1989, pupated 28 Apr, photographed 1 May, 27mm, male (89/22D); centre, lateral view, collected 28 Mar 1989, pupated 25 Apr, photographed 1 May, 22mm, female (89/22C); right, female ventral view, collected 9 Dec 1990, pupated 16 Dec, photographed 20 Dec, 32mm (90/106G).