Pyrrhochalcia iphis (Drury)

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 : 11-13

Pyrrhochalcia iphis (Drury) ( Figure 1 )

Food plants

Food plant records include Baphia nitida (Fabaceae) in Ghana ( Forsyth 1966) and Acridocarpus longifolius (= smeathmannii) ( Malpighiaceae ) in Côte d’Ivoire ( Vuattoux 1999). Sourakov & Emmel (1997) report it on Psychotria calva (Rubiaceae) in Ghana. In addition, Larsen (2005a) reports Dissotis (Melastomataceae) , Anacardium (Anacardiaceae) and several unidentified plants. Thus, it appears to be rather polyphagous.

However, several records from coconut ( Cocos nucifera ) need to be challenged. I have traced these back to a single report by the Department of Agriculture entomologist in Gold Coast, W.H. Patterson, who in his annual report for 1921 ( Patterson 1922), as summarised in the Review of Applied Entomology (1922, p. 213), recorded “Larvae of the Hesperid [sic] butterfly, Pyrrhochalcia iphis, Dr. , were in one instance very destructive to the leaves [of coconut], but were eventually controlled by parasites.” This record was the basis of the inclusion of P. iphis as a coconut pest in Lepesme’s (1947) definitive “ Les insectes des palmiers ” and most probably Forsyth’s (1966) “ Agricultural Insects of Ghana ”, so that the record has become established in the agricultural literature and repeated ever since, e.g. Mariau (2001), but with no further corroboration. T.B. Larsen (pers. comm. 2010) has suggested that the original record was a misidentification for Pteroteinon laufella (Hewitson) (Hesperiinae) , a well documented pest of palms in West Africa, which like Pyrrochalcia iphis has black wings flushed with metallic green. A similar case can be made with respect to the record of Coeliades bixana Evans (= Rhopalocampta bixae ) as discussed under that species below. D. Mariau may have suspected this, since in Mariau et al.’s (1981) account of the insect pests of coconut and oil palm in West Africa, neither P. iphis , nor C. bixana are mentioned, and in Mariau (2001) he pointed out “The description of the adults of R. bixae and P. iphis is very similar to that of P. laufella ”. For a general entomologist, which W.H. Patterson would have been, Pyrrochalcia iphis and Pteroteinon laufella could easily be confused. I find this explanation plausible (see also discussion under Natural enemies below).

Caterpillars

I have not reared this species, but I have seen and photographed large caterpillars in Côte d’Ivoire ( Figure 1 ) on two different unidentified food plants, one a tree sapling ( Figure 1 , above) and the other a vine. Carcasson (1981) illustrates the caterpillar, and I have examined blown caterpillars in the NHM (The Natural History Museum, London) dry early stages collection, which were reared by W.J. Ansorge in 1902 at Degema, southern Nigeria (although incorrectly labelled as Degema, Niger). Sourakov & Emmel (1997) provide some biological notes and illustrate the caterpillar head and three caterpillars on all sides of a thin stem of P. calva , clearing the epidermal layer from the stem. Larsen (2005a) summarises available information.

The caterpillars are reported to rest openly on leaves in small groups until the final instar which is solitary. Caterpillars of the final instar rest singly, aligned with their heads upwards, on leaves that hang down from their base ( Figure 1 , above). This is the only hesperiid species whose caterpillars behave in such a way as far as I know. This behaviour and the caterpillar colouring and pattern are probably warning colouration to show that they are distasteful, but I am not aware of any experimental test of this. Since the caterpillars seem to accept a wide range of food plants, this suggests that they synthesise one or more distasteful compounds, rather than sequester them.

I have not seen the early instars, but the feeding damage shown in Figure 1 (above) suggests that the first instars may make shelters at the end of a leaf similar to those made by other Coeliadinae , i.e. by making two major cuts from each side of the leaf lamina, and folding a shelter lid from each side with the bridge adjacent to the midrib. The damage on all three leaves in Figure 1 (above) suggests this sort of behaviour, described in more detail below for other species of Coeliadinae . Maybe the first instars have not synthesised enough deterrent chemicals to effectively discourage predators, and so need to use leaf shelters?

Pupa

Carcasson (1981) illustrates the pupa as well as the caterpillar, and W.J. Ansorge’s material in the NHM dry early stages collection includes emerged pupae. In Carcasson’s illustration, the pupa is pale brown with small black markings, the thorax yellow with small black markings. What appears to be a small backward pointing hook on the dorsum of the prothorax is actually the projecting T1 left spiracle. The illustration suggests that the pupa does not appear to be covered in white waxy powder, and this is confirmed from the NHM specimens. There is a short, blunt frontal protuberance, not clearly visible in the illustration.

Natural enemies

According to the summary in the Review of Applied Entomology, Patterson (1922) reported that an outbreak on coconuts in Ghana (Gold Coast) was “eventually controlled by parasites”, but as discussed above under Food plants, this record from coconuts is most likely a misidentification for Pteroteinon laufella . Based on Patterson’s report, Lepesme (1947) implied that several species of parasitoids were involved (“par plusieurs ennemis naturels”), but that is not explicit in the summary of Patterson (1922). Some years later, Nixon (1935) described a scelionid egg parasitoid, Telenomus thoas Nixon : “ GOLD COAST: Aburi (W. H. Patterson): very large series, mostly females, bred 15.xi.1921, from (presumably?) eggs of Pyrrhochalchia iphis Drury. The host is a pest of coconut and other palms.” When Nixon says that P. iphis attacks other palms, there is no documentation for this in the literature, which suggests that the information came from W.H. Patterson when he submitted the parasitoids for identification. Since Pteroteinon laufella does feed on other palms, this seems to be further support for the suggestion that Patterson misidentified P. laufella from coconut as Pyrrhochalchia iphis . Bearing in mind that Telenomus spp. are usually quite specialised in their host range, this also implies that T. thoas is an egg parasitoid of Pteroteinon laufella , and not of Pyrrhochalcia iphis . Unfortunately the type series of T. thoas in the NHM is preserved without the host egg remains (A. Polaszek, pers. comm. 2010)—had the eggs been kept with the parasitoids, it should have been possible to clarify the true host of the type series of T. thoas , and the identity of the hesperiid that Patterson reared from coconut. The eggs of Pteroteinon laufella are attacked by at least one egg parasitoid ( Mariau & Morin 1974) but that is reported as a Trichogramma sp. (Trichogrammatidae) .

Figures

FIGURE 1. Probably fifth (or sixth) instar caterpillar of Pyrrhochalcia iphis on unknown food plant, Forêt du Yapo, Côte d’Ivoire; above, in situ with feeding damage and possible old shelter remains, 10 Dec 1988 (88/216); below left, same individual; below right, detail of head of mature caterpillar on unknown food plant, 14 Jun 1989 (89/216).