Cocoon For Eggs

The Lady Bird Spiders (Eresus cinnaberinus) are found in the North Western Europe and Mediterranean. They live in vertical burrows lined with silk and are usually found on sunny slopes among stones and heather, well protected from wind.

The silk lined burrow serves as a home for the spider as well as a trap for its prey. A tangled mass of strands of fluffy silk is at the entrance of the trap. There are brown trip wires that extend from the entrance and connected to objects close at the entrance. When an unwary insect gets stuck and struggle to escape, the trip wires vibrate. The spider feels the vibrations and quickly climbs up the burrow and grabs its meal. The spider mostly prefers beetles as its food.

The male spider grows up to 11mm. A mature male acquires a bright reddish color with four black spots. Its front legs are black with white rings, while the back legs are red. The male looks very colorful (hence the name, Lady Bird), when it leaves its burrow in summer during May, in search of a female.

On reaching the burrow of the female, the male plucks the trip wires in just the right way to announce its arrival. The female feels the trip wire vibrations. The female becomes receptive and mating occurs. The male dies after mating, its life span stretching less than a year.

The female spider, which is larger than the male, grows to 16mm. It is black in color. It stays in its burrow and never leaves. It lives for about three years. After mating is over, the female lays about 80 eggs.

The eggs are protected in a cocoon of silk spun by the female. The cocoon is camouflaged with debris. The female guards the cocoon with great care. Everyday, during daytime, the cocoon is moved up to the top of the burrow and is warmed up in the sun. The cocoon is brought down to the bottom at night. The female performs this exercise everyday to regulate temperature of the eggs.

The eggs hatch in July or August. The small spider lings are fed on the regurgitated food by the mother spider. The young spiders stay in the burrow with the mother and undergo molting six times and grow in size. They attain maturity in 3 to 4 years. At the approach of spring. The mother spider dies. The young spiders feed on the mother’s body and leave the burrow.

The Lady Bird spiders are a very rare species and is therefore one among the protected species of the world.