Butterflies of Indonesia
Butterflies of Indonesia: overview
Indonesia is an archipelago of more than 17,000 islands at the intersection of two biogeographic regions: the Oriental (Asian) and Australian. Wallace's Line, separating these regions, runs through Indonesia between Borneo and Sulawesi.
The result is extraordinary biodiversity: by conservative estimates, more than 1,600 species of day-flying butterflies, though the country is unevenly studied. Indonesia is the world capital of birdwings.
Birdwings: the largest butterflies on Earth
Birdwings (genera Ornithoptera, Troides, Trogonoptera) are the largest butterflies on Earth. The largest representative — Queen Alexandra's birdwing (Ornithoptera alexandrae) from New Guinea — reaches a wingspan of 28 cm.
On the Maluku Islands (Moluccas) lives Croesus' birdwing (Ornithoptera croesus) — the golden-orange male is considered one of the world's most beautiful butterflies and is strictly protected under CITES.
Key islands
Borneo
Indonesia's largest island (shared with Malaysia and Brunei). Richest in diversity: more than 800 species of day-flying butterflies, including birdwings, large swallowtails, and nymphalids. Borneo's tropical forests are among the main biotopes for observation.
Sulawesi
A unique island with high endemism — east of Wallace's Line, giving a mix of Asian and Australian elements. Many genera are represented by endemic species found nowhere else.
Java and Bali
Densely populated islands with heavily altered ecosystems, but mountain forests remain. Several unique swallowtail species live in Java's mountains.
Conservation
Trade in birdwings is banned under international agreements (CITES). Tropical forest logging is the main threat to Indonesian butterflies. Several species are on the brink of extinction.
Observation season
Indonesia is equatorial; butterflies fly year-round. The best time depends on the island: on most, the dry season (May–October) is preferable for observation due to less rainfall.