Butterfly populations are a very good indicator of the health of an area's ecosystem !!
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 an obnoxious yellowish fluid from glands in the joints of the legs. (Like all butterflies protected in this manner, the Coster 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.