Buru opalescent birdwing  (Troides prattorum)

Confined to the island of Buru, Indonesia (4), this huge and spectacular black and yellow butterfly is named for the unusual, opalescent gloss of the male's hindwing (4) (5) (6). The hindwings are golden yellow and display a striking iridescent blue-green sheen when viewed at an angle (2) (4). The hindwing of the female Buru opalescent birdwing is mostly suffused with black, but an iridescent sheen may be present on the restricted yellow areas (7).

As its common name implies, the Buru opalescent birdwing is endemic to Buru Island, Indonesia (4).

Known mostly from the mountain forests of the Buru's interior, on the high plateau in the west and centre of the island (5) (7).

Buru Island has long remained relatively inaccessible, and very little is therefore known about the life-history of the Buru opalescent birdwing (4). However, there are certain biological characteristics known to be common to most, if not all, birdwing butterflies. The adults of all Troides species feed on the nectar of flowers, and the larvae on the leaves of Aristolochia and Pararistolochia plants (both in the family Aristolochiaceae) (8). The eggs are normally laid on these plants, and 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 acids that make the caterpillars toxic and therefore unappealing to most predators (9). The caterpillars eventually pupate and undergo metamorphosis into adult butterflies, and may even manage to maintain this toxic acid in their tissues into adulthood (9). Troides birdwings typically pupate on the twigs or stems of plants close to the larval food plant or on the food plant itself (6).

Major threats to Troides butterflies include deforestation due to logging and agricultural intensification, although since this is a moderate to high altitude species, it is probably at less risk than similar species at low elevations (10).

In the years between 1965 and 1979, Buru was a 'rehabilitation centre' for political prisoners, and entering the island was virtually impossible for foreign travellers (4). In addition, certain native tribes had a reputation for extreme aggression, which deterred potential collectors from visiting the island (6). Thus, the inaccessibility of the island has certainly been to the advantage of the Buru opalescent birdwing. Furthermore, its listing on Appendix II of the Convention on International Trade in Endangered Species (CITES) helps protect this endemic butterfly from excessive trade to international collectors (3), and therefore over collection from the wild. In recent years, villagers have learned to farm the butterfly, and reared specimens are now available on the international market, reducing pressure on wild individuals (5).

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