Andronymus marina Evans, 1937

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 : 45

Andronymus marina Evans, 1937

This species is restricted to Uganda and Tanzania, where it is rare in the forests of Mpanda and Kigoma, but relatively common in Minziro. TCEC has reared this species several times from Minziro forest , in north-western Tanzania (Apr and Jun 1994, Dec 1994 – Jan 1995 and Jun 1997).

Life history

The food plant is Baikiaea insignis (= B. eminii ) ( Fabaceae , Caesalpinioideae ). The ova ( Figure 50.1 ) are laid on tender young foliage of saplings in deep shade in the forest. The newly emerged caterpillars cut and roll a portion of a leaf in which to hide ( Figure 50.2 ). They develop very quickly, a necessary adaptation if they are to pupate before the leaves of the food plant harden and cease to be nutritious. The large larvae seem to eat continuously, and develop at a phenomenal rate. The leaves of the sapling food plant are very large and soft, and fall in folds, and so the larger larvae do not need to make shelters. They pupate among the leaves, not in shelters. Both the caterpillars ( Figure 51 ) and the pupae ( Figure 52 ) are astonishingly brightly marked, with distinctive rows of black marks on a pale or yellow background, not seen on other members of the genus, or indeed any other Afrotropical Hesperiinae so far, and can only be compared with some of the brightly coloured Coeliadinae , particular Pyrrochalcia iphis (Drury), where warning colouring of a distasteful species is thought to be involved ( Cock 2010). We have traced no observations that Baikiaea spp. are toxic or distasteful, so it seems unlikely that A. marina is sequestering toxins. If this is the case, the brightly coloured early stages of A. marina could reflect synthesised toxins, or it could be mimicking some other unknown distasteful organism in the environment.

Figures

FIGURE 50. Early stages of Andronymus marina, collected on Baikiaea eminii, Minziro Forest, Kagera, Tanzania, TCEC. 1, stage 1 leaf shelter, 6 Apr 1994; 2, ovum, dorsal view, 4 Dec 1994.

FIGURE 51. Final instar caterpillar of Andronymus marina, collected on Baikiaea eminii, Minziro Forest, Kagera, Tanzania, 13 Apr 1994, TCEC. 1, dorsal view; 2, dorsolateral view.

FIGURE 52. Pupae of Andronymus marina, collected on Baikiaea eminii, Minziro Forest, Kagera, Tanzania, photographed 13 Apr 1994, TCEC. 1, dorsal view; 2, lateral view. Emerged pupae in ABRI are 25–27mm long.