Atlas Moth

THE WORLD'S LARGEST INSECT

The subcontinent of India is home to many curiosities of the natural world. Of the vast variety of insects, some have not even been discovered, others have not been studied comprehensively.


Wide wing-span

Moths and butterflies comprise one of the largest orders of insects. With a few exceptions, moths are largely nocturnal insects. Among the better-known moths, the Atlas moth is the largest insect, in terms of wing area. A female Atlas moth may measure over 30 cm in wing-span. This means the measurement from one wing tip to the other when the wings are spread out on the sides.

In Burma, where this moth is more abundant than in India, local people call it see lipia or Elephant moth. It is so named not only for its great size but also for its powerful flight, usually at the level of tree-tops. In flight, the moth is easily mistaken for a small bird.

Atlas moths are a magnificent gold and purple-brown in colour. The wings have huge eye-shaped designs at the centre which scare off predators when the wings are opened suddenly. The upper tip of the forewing is reminiscent of a snake's head This feature is found in related species throughout the tropical world.

Homing in
A characteristic feature of these moths is their antennae. The antennae of male moths are feathery, while those of females are not as feathery. The antennae play an important role in attracting the male to the female.
Female Atlas moths release a stimulating (to males of the same species) scent, called
"pheromone". Male moths, with the help of their antennae, are able to detect the tiny quantity of scent released by a female several kilometres away. They home in on the female by comparing the quantity of molecules striking each antennae which leads them to the source of the scent. Males that have lost one antenna are greatly handicapped in locating the female, and those that have lost both, do not stand a chance.

In insects, the female is usually larger, since she has the task of carrying the eggs that will become the next generation. Females of some moth species carry over 500 eggs in their body. It is the female whose gumption ensures the survival of the young ones. She lays her eggs on a suitable plant so that the little caterpillars can begin feeding on its leaves soon after they hatch out. The female moth also makes sure that her eggs are in an inconspicuous place, out of reach of hungry predators who make a meal of them even before they have emerged.

Flying for food

Atlas moths live in humid forests over the greater part of the Indian subcontinent. Atlas moths feed on a wide range of food plants--over twenty different shrubs and trees. During the course of their short lifespan Atlas moths travel quite far in search of their foodplants. In the Himalaya, they fly up to an elevation of 1600m, and in the Nilgiris up to an elevation of 1500 m, where high foodplants grow.
With the rapid destruction of humid forests, which are their home, Atlas moths are in danger. The Indian subcontinent would certainly be poorer with the loss of one of its unique jungle denizens.