Artitropa Holland , 1896

Cock, Matthew J. W., Congdon, T. Colin E. & Collins, Steve C., 2015, Observations on the Biology of Afrotropical Hesperiidae (Lepidoptera). Part 8. Hesperiinae incertae sedis: Dracaena Feeders, Zootaxa 3985 (3), pp. 301-348 : 308-310

Artitropa Holland, 1896

This genus is restricted to the Afrotropical Region, including the Comoro Islands and Madagascar. It was established by Holland (1896) with erinnys Trimen as type species. Riley (1925) and Evans (1937) both revised the genus, and by the time Ackery et al. (1995) published Carcasson’s catalogue, eight species were recognised, three from Madagascar and five from mainland Africa. Further species have since been described from the Eastern Arc Mountains of Tanzania and from São Tomé and Principe. In view of subsequent observations and collections by ABRI, the genus is overdue for a further revision, for which the life history information reported here should be useful.

Riley (1925) commented on the ‘preponderance’ of females in his material. Of the 86 A. comus (Stoll) and A. erinnys Trimen he examined, there were 52 females and 34 males. Reared material of A. milleri Riley at ABRI suggests if anything a preponderance of males. It is likely that the caterpillars and pupae of females are slightly larger than those of the males and so may take slightly longer to complete development; in which case, where a brood of caterpillars develop from ova laid on one occasion by one female, it is possible to make a collection after the male pupae have emerged and obtain a preponderance of females. Riley (1925) illustrates the pupae and final instar caterpillar skins of A. erinnys vansomereni Riley and A. comus (including A. reducta Riley ), and discusses the differences in the markings of the head capsules.

The ova of all Artitropa spp. treated here are similar, and we have not documented any specific differences. All species seem to have ova of a similar size, but we have only documented the size for collections of A. erinnys vansomereni .

Larsen (1991, 2005) anticipates that all species of the genus feed on Dracaena spp. and our experience suggests he is correct. Larsen (1991) also generalises that they fly in the morning, evening and on dull days. Adults are rarely seen on the wing, although the early stages are easy to find, once the food plant is located. Thus, the only member of the genus that TCEC has knowingly seen on the wing is A. milleri milleri and that only because it flies at dusk in his garden at Mufindi, Tanzania. Similarly MJWC has seen only A. erinnys vansomereni on the wing in a Nairobi garden late in the afternoon.

The species are presented below in a sequence based on the final instar caterpillar head markings, showing the transition from those with a single spot on the face ( Artitropa sp. SCC01, Artitropa sp. SCC02 and A. cama ) like Gamia spp., to those with a strongly bilobed spot or rounded V-shape ( A. milleri ) to those with two spots ( A. principetome Collins & Larsen , A. comus and A. reducta ), four or six spots (variable, A. erinnys ), seven spots ( A. usambarae Congdon, Kielland & Collins , Artitropa sp. SCC04), nine spots ( A. boseae ), and 11 spots ( Artitropa sp. SCC03). We do not assume that this represents a phylogenetic sequence, although this is a possibility.