A pale green ghost in the Medog night
Medog, Tibet, August 2024. Even in a region famous for spectacular insects, this one stopped me cold: wings the colour of new leaves, each hindwing drawn out into a long, elegant tail. The Indian moon moth does not hurry. It drifted through the warm, damp air of the rainforest as if the night belonged to it, and for a few minutes, it did.
This is Actias selene, the Indian moon moth, a member of the giant silkworm family Saturniidae (order Lepidoptera). It belongs to the same group as the Chinese moon moth, Actias ningpoana, which for a long time was treated as a subspecies of A. selene before being raised to full species status. Moon moths have no functional mouthparts as adults; they never eat, and their whole winged life is a short sprint to find a mate and lay eggs before running out of fuel.
The caterpillars are leaf-eaters, chewing their way through a range of broad-leaved trees and shrubs, and they are striking in their own right: green, plump, and studded with rows of knobs. By the time they spin their silken cocoons, they are among the largest moth larvae a forest can hide. Each generation waits out the winter as a pupa inside that cocoon, which is why the adults appear in such a narrow window of summer.
The long tails are more than decoration. Experiments suggest they help deflect the echolocation calls of bats, giving the moth a better chance of surviving its brief winged life. Seeing one in the wild is a reminder that the most beautiful things in the forest often have the shortest time to enjoy it.
