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 : 344

Artitropa discussion

When Riley (1925) revised the continental African species, he did not examine the genitalia, working on wing pattern and to a limited extent on early stages. Evans (1937) seems to have accepted Riley’s conclusions and only added two taxa. For his revision, Evans seems to have dissected only one male of each species, and not dissected the different subspecies of A. erinnys and A. milleri . Thus he dissected a male A. e. erinnys from Zululand (within KwaZulu-Natal, South Africa) which is representative of the type locality (Port Natal) and a male A.m. milleri from Katanga, DR Congo, which is not representative of the type locality (Tukuyu, Tanzania). Further genitalia dissections are needed to assess the present classification and the status of the putative taxa recognised here. We suspect that A. milleri may comprise at least two species, milleri and coryndon, but perhaps more, but these have yet to be assessed based on their genitalia (T.B. Larsen in prep.) or by molecular methods.

The head markings of the caterpillars are more useful for separating species and species-groups, than for discriminating between subspecies of Artitropa . Thus, we can generalise that the caterpillars of A. comus , A. reducta and A. principetome are all very similar. Equally, there seem to be some differences between the caterpillars of the different populations / subspecies of A. erinnys and A. milleri , but our observations have not been sufficient to adequately document the degree and frequency of individual variation within populations. Our impression is that populations are generally quite consistent, but that atypical markings are not that rare. For example, we have reared A. erinnys vansomereni frequently, and although the markings are normally similar to the individual shown in Figure 26.2, individuals with much lighter head markings (Figure 26.3) and much darker head markings (Figure 26.4) were also documented. Again, the limited sample of three photographed individuals of A. erinnys comoranum ( Figure 34 ) can each be matched up with a separate mainland population of A. erinnys .

We are well aware that several species co-occur in eastern Africa, so that just because the caterpillars of one species are found on a Dracaena sp. at a locality, it does not mean that nearby ova are of the same species. On one occasion, Ivan Bampton found three ova on one leaf of a large-leaved Dracaena sp. ( steudneri or mannii ) in deep shade in the Usambara Mountains, and raised a different species from each: A. milleri milleri , A. erinnys ehlersi and A. usambarae . This adds a degree of uncertainty to observations on the ova and early instars (and their natural enemies), which cannot be distinguished.

The caterpillars of several species have been shown to have the anal plate dark ( Figures 26 , 30 , 37 ) or to have a double spot ( Figure 9 ). Sevastopulo (unpublished) referred to the markings of the posterior portion of the caterpillar of A. erinnys and A. reducta resembling a lizard head, and TCEC has compared the markings of A. cama ( Figure 9 ) to eyes. Janzen et al. (2010) have postulated that the conspicuous eye markings on the head of Hesperiidae caterpillars and pupa serve to frighten small insectivorous birds that may open leaf shelters. Given that many leaf shelters, including those or Artitropa spp., can be opened at either end, then it seems reasonable to suggest that anything that suggests a pair of eyes on the posterior end of the caterpillar could have a similar function.

Figures

FIGURE 9. Early stages of Artitropa cama [TCEC]. 1, ovum, dorsal view, collected on Dracaena? mannii, Ntakatta Forest, Mpanda, Tanzania, 20 Jun 2000; 2, ovum, lateral view, as # 1; 3, head of final instar caterpillar, anterodorsal view, collected on D. (almost certainly) mannii, Zambezi Rapids, Zambia, 25 Oct 2004; 4 – 5, head of final instar caterpillar, as # 1, 15 Jun 2000; 6, final instar caterpillar, dorsolateral view, as # 4; 7, pupa, anterodorsal view, as # 1, 7 Jul 2000; 8, pupa, dorsolateral view, as # 7.

FIGURE 26. Final instar caterpillar of Artitropa erinnys vansomereni, on Dracaena steudneri. 1, dorsolateral, anterior and posterior views; collected Thika, 2 Jul 1988; photographed 18 Jul; pupated 24 Jul, 88 / 52 A 1; 2, head, anterior view; collected Nairobi; photographed 13 Sep 1988; 88 / 75 A 1; 3, head with atypical light markings, anterolateral view; Nairobi, 17 Jan 2006 [TCEC]; 4, head with atypical dark markings, anterior view; Nairobi, 23 Dec 2002; 5, dorsolateral view, Nairobi; photographed 25 Nov 89; 89 / 94.

FIGURE 30. Caterpillar and adult of Artitropa erinnys nyasae collected as ovum on Dracaena sp. probably steudneri, Lilongwe, Malawi, 22 Jul 2001, MJWC 01 / 101. 1 – 2, second instar caterpillar; moulted to second instar 31 Jul; photographed 1 Aug; moulted to third instar 4 Aug; 11 mm: 1, detail of head, anterodorsal view; 2, dorsal view; 3 – 5, fifth, final instar caterpillar, moulted to fifth instar approx. 18 Aug; photographed 28 Aug; pupated 5 Sep; 45 mm: 3, posterior segments, dorsolateral view; 4, head and anterior segments, anterodorsolateral view; 5, head, anterodorsal view. 6, adult male underside, emerged and photographed 10 Oct; note the left forewing and hind wing are distorted at the tornus where the silk girdle dug into the pupa wings.

FIGURE 34. Early stages of Artitropa erinnys comoranum, collected on Dracaena reflexa, Grande Comore, Comoro Islands; 1 – 4, final instar caterpillar; 5, pupa. 1, 3 – 5, Moroni, 3 – 9 Sep 2014 [© Alain Gauthier]; 2, 13 Apr 2004 [TCEC]. 1, dorsal / dorsolateral view in shelter; 35 mm; 2, detail of head, anterior view; 3, detail of head, anterodorsolateral view; 4, detail of head, anterodorsolateral view; 5, newly formed pupa, dorsolateral view.

FIGURE 37. Final instar caterpillar of unknown Artitropa sp. SCC04 collected on Dracaena sp., Anjozorobe, central Madagascar [SCC]. 1, detail of head, anterior view, 21 Nov 2006; 2, dorsolateral view, 11 Dec 2006; 3, dorsal view, 11 Dec 2006.