Sunday, October 27, 2013

Glassy Tiger

The thirteenth butterfly in the 'Butterflies from my garden' series is the Glassy Tiger (Parantica aglea ).

This is quite a common butterfly in India, and it is mimicked by many other butterflies like the Tiger Brown, Courtesan male, Siren, Great Blackvein and female of the Common Wanderer. So why do the butterflies have this mimicry? This was nicely explained by Peter Smetacek in his book "Butterflies on the roof of the world" but to summarise ; Certain butterflies during their caterpillar stage feed on plant poisons, which are then stored in their bodies. During its adult stage this distastefulness is advertised by bright warning colours and patterns. Predators who catch and eat such butterflies experience a lot of unpleasantness like strong heartbeat and vomiting. The predator learns to stay away from such butterflies.

Some butterflies cannot digest and store the plant poisons, so these butterflies mimic the patterns of the distasteful species and survive on their reputation. They even have flight patterns that mimic these butterflies. The glassy tiger had acquired the toxins from the milkweed plant during its caterpillar days, hence its distasteful. Hence so many other species mentioned above imitate it.