25-5-2023 SUKAU RIVER LODGE, BORNEO - HORSFIELD'S BARON BUTTERFLY (FEMALE) (Tanaecia iapis)

The Horsfield's Baron is dimorphic, in that the male has a velvety black upperside with a broad bright blue marginal border on the hindwings. The female is pale greyish ochreous brown and is often confused with Tanaecia pelea (Malay Viscount) or one of the Euthalia species.

The species is relatively common in Singapore - the males more often encountered along sunny footpaths. The butterfly has an interesting habit of gliding back to a favourite perch, often on the edge of a large leaf, and settles just out of reach of the observer.

Sometimes, three or four males are seen together around the same territory, frolicking with each other in the sun. The Horsfield's Baron is very often encountered in the western area of the nature reserves, particularly in the Chestnut Track and Mandai Track of the western fringe of Upper Peirce Reservoir.