The Southern Birdwing (Troides minos), one of India’s largest and most spectacular butterflies, is drawing attention for an extraordinary survival mechanism that protects it during one of its most vulnerable life stages. Endemic to the Western Ghats of Karnataka and Kerala, this magnificent butterfly has a wingspan ranging from 140 to 190 millimetres and is the official state butterfly of Karnataka.
Unlike most butterfly pupae, which remain completely motionless when threatened, the Southern Birdwing pupa actively defends itself. When disturbed, it wiggles its body and produces a distinctive “pha-pha” squeaking sound through a process called stridulation. This sound is created by microscopic sound-producing plates on the abdominal segments rubbing against each other. The unexpected vibration startles predators such as birds and small rodents, increasing the pupa’s chances of survival.
The butterfly also benefits from chemical protection. As a caterpillar, it feeds on host plants that contain toxic compounds, storing these chemicals in its body. These retained toxins make both the caterpillar and pupa unpalatable to many predators.
Although the Southern Birdwing is not currently considered threatened, conservationists emphasize the importance of protecting the Western Ghats’ forests and maintaining long-term monitoring. Preserving its natural habitat will ensure this remarkable butterfly and its unique adaptations continue to thrive in one of the world’s richest biodiversity hotspots.