Butterfly of the Month - October 2023

The Capaneus Swallowtail (Papilio capaneus capaneus, formerly P. fuscus capaneus) is an impressive butterfly. The male reaches a wingspan of 85mm while the female even exceeds that with 91mm. Because of its size and dark colour, the adult is often mistaken for the male Orchard Swallowtail (P. aegeus). However, a good observer will notice the differences.

While the Orchard Swallowtail is not only taller, its base colour is also black, whereas the wing colour of the Capaneus Swallowtail (previously called Fuscous Swallowtail) exhibits a dark brown. Additionally, our current butterfly of the month has a distinct tail at the end of the hindwing which the Orchard Swallowtail and most of our swallowtails don’t possess.

Like most of our butterflies, this species shows a different appearance when looking at the upper or underside of the wings. When viewing the open upper wing pattern, you’ll see a narrow white coloured marking running across, widening towards the front edge. The hindwing displays a large white patch, some faint light blue half-moon shaped markings and a series of orange-red ones.

While the forewing on the underside is almost identical to the upper side, the markings are less distinct. The white on the hindwing is much reduced in size and segmented into individual spots, and the blue and orange-red markings at the outer wing edge tend to be much stronger than on the underside.

The butterfly starts its life cycle with a small globular egg, light yellow in colour, and with a smooth surface like other species in the Papilionidae family. The egg is laid singly, as our image shows, on the upper side of its host plant’s leaf.

Larvae may vary in colour, are often brown orange, sometimes brown with white, or green with variations of patterns and light markings plus a white line running along the larva’s body.

The pupa is usually green a little more compact looking than that of i.e. the Orchard Swallowtail.

Papilio capaneus capaneus larvae feed on a variety of native plants belonging to the Rutaceae family. In Brisbane its favoured native hosts are Finger Lime (Citrus australasica) and Lime Berry (Micromelum minutum). Gardeners may encounter the butterfly laying eggs on their citrus trees.

Images:

AV – Aviceda, CC BY-SA 3.0; CM – Cliff Meyer; PC – Peter Chew, Brisbane Insects; RM – Robert (Bob) Miller