Borneo birdwing  (Troides andromache)

Birdwings are large, tropical butterflies of the Papilionidae family and include arguably some of the most spectacular, butterfly species in the world. Troides birdwings are known for the striking contrast of their black and yellow colouration. The male of this birdwing species, Troides andromache, has yellow hindwings with black borders and veins. The forewings are primarily black, but on the underside, show whitish streaks towards the outer edge of the wing. The female can be distinguished from the male by its paler-coloured forewings, which are primarily whitish to tan-brown, and its different pattern of black and yellow on the hindwings (3).

Troides andromache is endemic to the island of Borneo (3). There are two subspecies of this birdwing: Troides andromache andromache occurs in Sabah, and Troides andromache marapokensis occurs in northern Sarawak. The Indonesian part of the island (Kalimantan) is not well researched, and it is not known whether the species also occurs there (4).

Native to montane forests, where it is recorded from around 1,000 to 2,900 metres above sea level (5).

Little has been documented on the biology of this species, but there are certain biological characteristics known to be common to most, if not all, birdwing butterflies. After mating, females immediately seek out appropriate host plants on which to lay their eggs, usually on plants of the genera Aristolochia and Pararistolochia (both in the family Aristolochiaceae), on which the caterpillar larvae subsequently feed (6). Once the caterpillars hatch, they voraciously munch through the leaves around them. Feeding upon these plants also serves as a defensive mechanism, as they contain certain chemicals that make the caterpillars toxic and therefore unpalatable to most predators (7). The caterpillars eventually pupate and undergo metamorphosis into adult butterflies, and may even manage to maintain toxic chemicals in their tissues into adulthood (7). Troides birdwings typically pupate on the twigs or stems of plants close to the larval food plant or on the food plant itself (3). Adults of this species feed on nectar of Mussaenda blossom and other flowers (5).

The principal threats to Troides butterflies are deforestation and pressure from an increasing human population (4) (9). The Troides andromache population at Mount Kinabalu is under considerable threat from human ‘development', and this beautiful butterfly has now sadly disappeared from many of its former localities around Mount Kinabalu, Sabah (4) (6). Little current data seems to be available on the status of this butterfly elsewhere (4).

This endemic butterfly is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in this species should be carefully monitored (2). Additional protection is afforded to Troides andromache in the Kinabalu area, where it occurs within the boundaries of National Park lands around Mount Kinabalu (4) (8).

Authenticated (05/08/08) by John Tennent, Scientific Associate, Department of Entomology, The Natural History Museum, London.