24-11-2016 INLE LAKE, MYANMAR - TAWNY COSTER BUTTERFLY (Acraea terpsicore)

Acraea terpsicore, the tawny coster, is a small, 53–64 millimetres (2.1–2.5 in), leathery-winged butterfly common in grassland and scrub habitats. It belongs to the Nymphalidae or brush-footed butterfly family. It has a weak fluttery flight. It is avoided by most insect predators. This species and the yellow coster (Acraea issoria) are the only two Indian representatives of the predominantly African tribe Acraeini. It is found in India, Sri Lanka, Maldives to Myanmar, Thailand, Laos, Cambodia, Vietnam, Bangladesh, Singapore, and recently Australia.

This species does not fly high, but seems to keep within 3 m of the ground and tends to rest on vegetation in the regions of a meter off the ground. Acraea terpsicore can be seen in abundance wherever its larval food plant (Passiflora species) is found. The adult tends to avoid dense undergrowth and shady areas, instead keeping to open spaces in all types of vegetation.

The adult flies slowly with weak seemingly unsteady wing beats. It is one of the boldest butterflies, protected as it is from predators by a nauseous chemical. When attacked it plays dead and exudes a noxious yellowish fluid from glands in the joints of the legs. Like all butterflies protected in this manner, Acraea terpsicore has a tough exoskeleton which enables the adult to survive a few pecks of a bird or even the bites of a lizard. Once left alone the adult immediately takes off and resumes its uncaring flight.

When feeding on flowers, this butterfly is unhurried, often spending a long time sitting on the same flower. When sitting it either spreads its wings or closes them over its back the hindwings covering the forewings to a large extent. Sometimes the butterfly will not sit, but rest gently on the flower while feeding, while doing this, to maintain balance, it beats only its forewings while keeping the hindwings completely steady.