Celaenorrhinus proxima proxima ( Mabille 1877 )

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 : 10-14

Celaenorrhinus proxima proxima ( Mabille 1877) ( Figures 1.3–5 , 6–11 )

This species was described from Congo ( Mabille 1877), but is widespread from Sierra Leone to Kenya. TCEC has also found it in Minzoro Forest in north–western Tanzania. Evans (1937) described a second subspecies, toro, from Daro Forest, Toro, Uganda, which is larger, but with smaller spots, and Berger (1976) described a third subspecies maesseni from Ghana (type locality), Guinea and Côte d’Ivoire. The status of these subspecies will need further evaluation, as they are likely to be valid species. Thus, ssp. proxima is the Kenyan subspecies, but as noted above it has been confused with an undescribed species nr. dargei .

Adult behaviour See under C. undescribed nr. dargei above.

Food plants

I have reared C. proxima from Mimulopsis solmsii , M. alpina and Phaulopsis imbricata ( Figure 6.2 ) (all Acanthaceae ). Larsen (1991) gives Mimulopsis based on my rearing in Kenya. Both Mimulopsis spp. are common roadside plants in parts of Kakamega Forest, and for a time I confused the two in the vegetative state, although later I concluded that M. alpina has the petioles of the young leaves red, while those of M. solmsii are green. Mimulopsis is a montane genus, noted for synchronised flowering approximately every nine years ( Blundell 1987, M. Cheek pers. comm. 2011). I believe I have also found early stages of this or C. undescribed near dargei on a Brillantaisia Ovum

The ovum is laid on the leaf under surface in the middle of the lamina. It is rounded, with the base flattened, and the widest part well above the base; 0.81 mm diameter at widest; the hatched ovum is white, with about 60 fine ribs, joined by similarly fine lateral lines at right angles in close to a square grid.

Leaf shelters

The first shelter is oval. One measured about 6 x 4 mm and was cut from the edge of the leaf lamina (90/75); another measured 4 x 2.5 mm and was cut from the middle of the lamina, close to the egg. The second shelter is usually rounded with a diameter of about 12 mm (90/75), and again is cut from the edge of the leaf lamina. It may also be more clearly two-cut with the edge of the leaf forming a straight edge to the shelter ( Figure 7 ).

On one occasion I collected a pupa; it was formed in a shelter between two leaves of M. solmsii near Ikuywa Steam, Kakamega Forest (87/20B).

Caterpillar

My descriptions of the early stages of C. p. proxima are limited, partly because more comprehensive descriptions were prepared of material that wasn’t reared through that I assumed was C. proxima , but I now know could also have been C. undescribed nr. dargei . reared to pupa which died, but identified from pupal remains). 12 mm; head 2.81 x 2.65 mm wide x high; flattened on top; dark brown; shiny, rugose. T1 transverse plate, narrow dark on posterior margin. Body dull dark green with transparent cuticle, through which fat bodies give a lighter tone except along dorsal line; T2–A8 thin white dorsolateral line; slightly more diffuse lateral line; gonads on A5 light green, oval. All legs concolorous. The mature caterpillar grows to at least 23 mm. The penultimate instar is similar, with the head capsule 1.91 x 1.76 mm wide x high.

An n–3 instar caterpillar was collected on Phaulopsis imbricata , Kakamega Forest, 17 Jul 1990 (90/75): 6 mm; head dark brown ventrally, lighter dorsally, 0.86 x 0.86 mm wide x high; body dark translucent; gonads visible A5. In the next instar, the head measured 1.33 x 1.19 mm. Caterpillar instar durations recorded were n–2 7 days; n–1 10 days; final 18 days.

Pupa

Pupa reared from final instar caterpillar 87/20C. 17 mm; cremaster c. 1.5 mm; proboscis reaches tip of cremaster; strong, blunt frontal projection curved upwards and then back; similar but smaller projection on each eye. What purpose, if any, these serve is open to speculation. Colour shiny brown; darker on head, appendages, and transverse rows across dorsum of abdomen. The pupa illustrated ( Figure 9 ) died, but the remains were identified based on the projections over the eyes. Three pupae reared through under Nairobi conditions took 12, 13 and 16 days to emerge.

Natural enemies

A fifth instar caterpillar of either this species or C. sp. undescribed nr. dargei collected on Phaulopsis imbricata in North Kakamega Forest (31 Aug 1995, 95/117) was parasitized by a small gregarious tachinid fly, producing five external puparia, which failed to emerge. The puparia were slender, almost parallel-sided and measured 3.02 (2.67–3.33) x 1.28 (1.19–1.41) mm. Because C. p. proxima has been reared from P. imbricata , whereas C. undescribed nr. dargei hasn’t, I provisionally associate this record with the former host, although it seems likely that parasitoids will attack both species.

Observations from Cameroon

I collected caterpillars of what appear to be this subspecies in a patch of forest near Douala, Cameroon, 16 Jun 1990 on an? Acanthopale sp. (Acanthaceae) (90/205). However, Acanthopale is considered a montane genus (M. Cheek pers. comm. 2011) so the identification of this food plant from near sea level needs confirmation. Only one caterpillar was successfully reared, a female. It was collected as a penultimate instar caterpillar in a typical Celaenorrhinus stage 2 shelter, and moulted to the final instar the next day ( Figure 10 ). Newly moulted, it was 16 mm long. Head 3.04 x 2.90 mm wide x high (n=3); dark brown, shiny, rugose. T1 with light brown shiny dorsal plate down to level of spiracles, darker posteriorly. Body translucent, dark; slightly darker dorsal line; thin white dorsolateral line; diffuse orange dot above spiracle A8; anal plate tinged orange-red on lateral and posterior margins; spiracles pale. This differs from the caterpillar of C. proxima proxima from Kenya in the brown plate T1 which is almost transparent in Kenya material, and the diffuse orange spot A8 and orange-red colouring on the anal plate, neither of which was observed in Kenyan material. It pupated on 6 Jul ( Figure 11 ) and emerged 22 Jul.

The two previous instars were similar; the head capsule of the penultimate instar was 2.02 x 2.02 mm wide x high (n=2), while that of instar n–2 measured 1.38 x 1.38 mm.

oon, 16 Jun 1990; pupated 6 Jul; photographed 17 Jul; emerged 22 Jul; 90/205A. 1, detail of head of (3) lateral view. 2, detail of dorsal part of A1–5 of (3). 3, lateral view.

Figures

FIGURE 1. Frontal plates of pupae of Celaenorrhinus proxima group. 1, C. plagiatus female, collected as final instar caterpillar on Brillantaisia lamium, Forêt de Yapo, 4 Dec 1988, 88/203A. 2, C. undescribed nr. dargei male, collected as caterpillar on Mimulopsis solmsii, Kakamega Forest, 16 Jun 1991, 91/35. 3, C. proxima proxima female, collected as pupa on M. solmsii, Kakamega Forest, 1 Sep 1987, 87/20. 4, C. proxima proxima male, collected as caterpillar on Phaulopsis imbricata, Kakamega Forest, 19 Jul 1990, 90/75. 5, C. proxima proxima female, collected as caterpillar on?Acanthopale sp., near Douala airport, Cameroon, 16 Jun 1990, 90/205A. 6, C. proxima maesseni male, collected as caterpillar on unidentified Acanthaceae, Forêt de Yapo, Côte d’Ivoire, 4 Dec 1988, 88/202A (the projection over the eye on the left is crushed out of alignment).

FIGURE 2. Food plant and caterpillar probably of Celaenorrhinus plagiatus but perhaps of C. proxima maesseni. 1, flowering Ruellia primuloides, 4 Dec 1988, Forêt de Yapo, Côte d’Ivoire. 2, final instar caterpillar dorsolateral view, collected 4 Dec 1988 on R. primuloides, Forêt de Yapo, Côte d’Ivoire; photographed 6 Dec; parasitized by Apanteles (s.l.) sp. 9 Dec; 88/208A.

FIGURE 3. Celaenorrhinus undescribed species near dargei. 1, feeding on Justicia flava, Kakamega Forest, 6 Apr 1990. 2, from below, at rest on leaf, Kakamega Forest, 21 Sep 1991.

FIGURE 4. Celaenorrhinus sp. undescribed nr. dargei, collected as n–1 caterpillar on Mimulopsis solmsii, Kakamega Forest, 7 Jul 1991; moulted to final instar 1 Jul; photographed 7 Jul, 23 mm; pupated 17 Jul; 91/39B. 1, lateral view with anterior view of head. 2, detail of head, lateral view.

FIGURE 5. Details of final instar caterpillar head capsule and pupa of Celaenorrhinus undescribed nr. dargei, collected as n– 2 caterpillar on Mimulopsis solmsii, Kakamega Forest, 16 Jun 1991, pupated 31 Jul, adult male 12 Aug, 91/35. 1, anterolateral view of head capsule to show detail of microsculpture. 2, dorsolateral view of thorax. 3, dorsolateral view of abdomen showing spikes on anterior margin. 4, frontal view of frontal plate of pupa, with projections, those over the eyes angled at about 45°. 5–7, cremaster, ventral, lateral and dorsal views.

FIGURE 6. Food plants of Celaenorrhinus proxima proxima. 1, Brillantaisia sp. probably owariensis or cicatricosa, which needs confirmation as a food plant, Kakamega Forest, 5 Apr 1990. 2, Phaulopsis imbricata, Kakamega Forest (transplanted to Nairobi), 22 Nov 1990.

FIGURE 7. Diagram of stage 2 leaf shelter of Celaenorrhinus proxima proxima on Mimulopsis solmsii, Kakamega Forest, 1 Sep 1987, 87/33; approximately life size. Light grey is the under surface of the leaf turned over to form the shelter; mid grey is the leaf upper surface; next to the shelter is a shelter that has been cut out, but not turned over.

FIGURE 9. Pupa of Celaenorrhinus proxima proxima, collected as final instar caterpillar on Mimulopsis solmsii, Kakamega Forest, 7 Nov 1987; pupated 27 Nov; date of photograph not recorded; failed to emerge, 87/33 (pupal remains identified based on the projections over the eyes).

FIGURE 10. Celaenorrhinus proxima proxima, collected as n–1 caterpillar on Acanthopale sp., near Douala airport, Cameroon, 16 Jun 1990; moulted to final instar 17 Jun; photographed 17 Jun; pupated 6 Jul; 90/205A. 1, dorsolateral view. 2, dorsolateral view with frontal view of head.

FIGURE 11. Celaenorrhinus proxima proxima, collected as n–1 caterpillar on Acanthopale sp., near Douala airport, Camer-