Fresna nyassae Hewitson, 1878

Cock, Matthew J. W. & Congdon, Colin E., 2013, Observations on the Biology of Afrotropical Hesperiidae (Lepidoptera). Part 5. Hesperiinae incertae sedis: Dicotyledon Feeders, Zootaxa 3724 (1), pp. 1-85 : 56-57

Fresna nyassae Hewitson, 1878

Evans (1937) treated this species as having four forms: plata Evans, 1937 from Uganda and western Kenya; nyassae Hewitson, 1878 (= roncilgonis Plötz, 1882 (in Plötz 1882–1883)) from Nigeria to Mozambique; joppa Evans, 1937 from Guinea across West Africa ( Larsen 2005) to Kenya and Tanzania; and ennuari Riley, 1921 from Congo to southern Sudan to Mozambique. The consistency of these forms and the degree of geographical overlap suggests the possibility that more than one species is involved and that further study is needed ( Larsen 2005). Life history information should contribute to this and so it would be important to link food plant and biology information to named forms. Because this is the only species of Fresna for which observations of the early stages are available, we present details here.

Food plants

Vuattoux (1999) reports that he reared this species twice from the exotic Paullinia pinnata (Sapindaceae) in Côte d’Ivoire. However, as discussed under F. netopha above, a voucher specimen reared from P. pinnata proved to be F. netopha , and it seems likely that Vuattoux actually reared F. nyassae from Afrormosia laxifolia . Based on Larsen’s (2005) observations this record should be form joppa .

Le Pelley (1959) lists Albizia sp. ( Fabaceae , Mimosoideae ) as the food plant of Fresna nyassae plata in Uganda, but does not give a source. Sevastopulo (1975) lists Albizia as the food plant of F. nyassae , and Sevastopulo’s rearing may well be the original source of this record, which is repeated in Kielland (1990), Larsen (1991), Ackery et al. (1995), Heath et al. (2002), and Larsen (2005).

Trimen (1893) redescribes what he treats as roncilgonis, but is actually ennuari, and includes a description of the caterpillar and pupa from Mozambique, with the food plant an unidentified small tree. Riley (1921) notes that in Zambia, H.C. Dollman obtained both typical nyassae and a paler form, which Riley described as ennuari based on material which Dollman considered to be a separate species. Dollman (unpublished) reared form ennuari in Zambia on a Fabaceae tree which he identified in the local language as ‘mutowo’, but did not paint the caterpillar. ‘Mutowo’ is the same species from which Dollman (unpublished) reared Andronymus philander (see above), which we have tentatively associated with the genus Isoberlinia ( Fabaceae , Caesalpinioideae ), which is close to Julbernardia .

R. Paré reared F. nyassae from Julbernardia globiflora ( Fabaceae , Caesalpinioideae ). Pringle et al. (1994) include a brief description of the ovum and caterpillar as do Henning et al. (1997), who also include Paré’s photographs of the mature caterpillar, pupa and adult female. The location of the original rearing is presumably Zimbabwe since although neither Pringle et al. (1994) or Henning et al. (1997) specify the locality, Woodhall (2005) gives the food plant as “unknown in South Africa, Julbernardia globiflora in Zimbabwe ”. R. Paré’s photograph of an adult female in Henning et al. (1997) shows that this material is also form ennuari .

Leaf shelters

Dollman (unpublished) describes the caterpillars of form ennuari making leaf shelters ‘of the simple type —that of the lightly stitched up leaf, forming a very loose cylinder—the larva being of course on the dorsal surface’.

Ovum

The ovum is rose pink and is laid on new growth (R. Paré in Pringle et al. 1994 and Henning et al. 1997).

Caterpillar

According to R. Paré (in Pringle et al. 1994) ‘the first instar larva is bright scarlet with a black head while later instars are whitish in colour with a brown head. The final instar is smooth and white with a discrete black dorsal longitudinal stripe on each segment except the first two and the last. The headshield is reddish brown with symmetrical orange markings’. R. Paré’s photograph of the final instar caterpillar in Henning et al. (1997) shows that in addition, there is a narrow black dorsal plate on T1; a black spot laterally on each of A3–A8; three dark triangular marks on the anal plate; and the head is wider nearer the base, indent at vertex; the orange markings comprise the face apart from dark markings: all sutures; the adfrontals, clypeus and frons; a straight line close to and parallel to the epicranial suture; a black spot on the epicranium level with the top of the adfrontals, and another below this; diffusely darker between this last spot and the adfrontals. Trimen’s (1893) description of the caterpillar is similar, except he mentions only one reddish brown spot on the face, and describes the anal plate as ‘semicircular, green, divided into five triangular portions by four white lines’.

Pupa

R. Paré’s photograph in Henning et al. (1997) shows the pupa to be smooth with no projections apart from a slightly protuberant T1 spiracle. It is brown, paler ventrally; a short, pale longitudinal mark on the anterior margin of segments A3–4; covered with a light dusting of white waxy powder, which also lines the interior of the leaf shelter. An emerged pupa of form ennuari from the Dollman collection in the Dry Early Stages Collection of The Natural History Museum, London, is similar, but instead of pale dorsal markings it has a weak dorsal line on the thorax and at the anterior margin of A2–3.

Discussion

Life history information is still rather scanty to draw conclusions, but the fact that H.C. Dollman found nyassae and ennuari together in Zambia but only reared ennuari does support his view that these may be separate species.