The Monarch’s Life Cycle

Published by drelayaraja
October 31, 2009, Category: Biology

This article is based on my observations on the Monarch butterflies. I have seen them along the milk weeds. They lay their eggs, feed and pupate on the milk weed plants.

I have taken photographs of their eggs, larvae, pupa and the emerging butterfly.

The Monarch’s Life Cycle

Image via Wikipedia

Monarch butterfly is an elegant Arthropods belonging to the genus Danus. They have pleasing orange wings decorated with black stripes and white spots. Both males and females look similar. They originated in the United States, but they can now be found in Southern Canada, Australia, India and the Pacific Islands. Monarch’s live for an average of 6 months or more.

They repose their eggs on the underside of the milkweed plant (Asclepias sp. and Calotropis procera) after feeding on the nectar of flowers.

Milkweed flowers – delicious meal for the larvae

Laying the egg

Emergence of Larvae and their Feeding

Metamorphosis of the monarch is spectacular, undergoing four changes in form during its lifetime. Their eggs are pin-sized and have a short incubation of 3-5 days. Tiny caterpillars measuring few millimeters emerge from these eggs.

This larval or caterpillar stage is characterized by smooth exoskeleton with stripes of black, white and greenish yellow. Two sets of feelers with hooks are present at both head and end of abdomen. The caterpillars shed their exoskeletons several times in their growth period lasting couple of weeks. A new layer of exoskeleton is formed before moulting.

The Transformation

After a fortnight of aggressive eating, the caterpillar gets ready for the next stage of development by suspending its feeding and becoming short and stout. It spins a clump of web on the milkweed and holds it with its caudal hooks, hanging downward. It remains dormant for several hours during which its stripes begin to fade and the larva swells to a larger size. After about four hours, the caterpillar uncurls stretching downward becoming long and straight, soon thereafter its exoskeleton starts to split, wrinkles and falls off.

The caterpillar now transforms into a beautiful chrysalis (pupa), shrinking until it is only 25 millimetres long. The whole process from when the caterpillar first hangs itself until it becomes a newly formed chrysalis is about 8-12 hours. Chrysalis is greenish in colour with bright golden spots on the upper rim.

After about 5-10 days the butterfly is ready to hatch, it splits open the chrysalis and emerges transformed. It will not fly until its wings have been warmed by the sun, resting until its wings have hardened and are ready for flight. Three to four generations of monarchs grow in a given year. While most insects hibernate, the monarch is the only species of butterfly which actually flies to warmer weather (migrates) during winter to a warmer climate.