Cocoons for Kids                                                                                            See Cecropia , Giant of the Night!
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Life Cycle

Life Cycle

The life cycle of the Cecropia moth is onivolting, meaning the cycle is completed once a year. In the late spring eggs are laid by the adult moth. The eggs are about the size of a pin head or grain of rice.  After 4 to 6 weeks the egg hatches and the caterpillar emerges.
The caterpillar is the larva stage of the life cycle. The cecropia larva sheds its skin 4 times during its period in order to make room for its incredible growth. The goal of the larva stage is for the caterpillar to eat as much as it can. This is the only time the insect receives nutrients, so it must eat enough to sustain life for the rest of the year.
Each time the larvae sheds its skin, it enters into a new instar. The Cecropia larva goes through five instars before making its cocoon. The image to the right shows a caterpillar (larva) in the second instar. Here is about an inch long and has yellow skin with black dots. Before a larvae sheds its skin, it weaves a small pack of silk for its hind legs to anchor onto. The skin sticks to the silk while the caterpillar wiggles out. Often times the caterpillar will turn around an eat the nutricious skin it just discarded. YUM!

The third instar. The caterpillar now has green skin. Its tubercles, protrusions from its back and head, have turned red, yellow, and blue. The tubercles have hard, tiny spikes all over them. This is the caterpillar's defense from predators. If attacked the caterpillar quickly thrashes its head around to fend off an attacker. 

In this image you can see all of the legs of the caterpillar. Insects are classified by having six legs in particular. So how is cecropia still classified as an insect? You will notice three pairs of legs near the head of the larva. These are the primary legs. The other legs are considered to be irrelevant since they only occur during this stage. 

This is the size difference between fourth(left) and third(right) instar. The fourth instar caterpillar has just shed its skin. Its new skin is very soft and its tubercles have not yet hardened. 

You can see the special padding on the tips of the legs of the caterpillars on the 4th instar caterpillar. This padding is shaped much like velcro and is very strong. It is so effective that the caterpillar can grab onto the grooves of your fingerprints and hold its own weight. 

The fifth instar is the largest this caterpillar will grow. They can become as long as 6 inches and as fat as a roll of quarters. The chalky skin and lathargic movements indicate it is time to spin the cocoon. The caterpillar will travel until it finds just the right spot for the cocoon. There's no telling why it chooses the place it does. Sometimes many caterpillars will migrate to the same spot although there is no evidence that they communicate or are social. Usually the caterpillar finds a comfy spot between some sticks or in the grooves of tree bark, and begins making its home for the winter. 
Cecropia spins its cocoon out of silk. You may be familiar with the Asian silk moth Bombyx Mori. Bombyx Mori has been domesticated for thousands of years. Cecropia however has not been domesticated at all. This allows for plenty of variety in colors, shapes, and sizes, especially in the cocoons. Here you can see the brown, red and white styles. The bottom cocoon still has the grass and leaves attached that the caterpillar used to build it. 
Although not a lot changes on the outside of the cocoon during the winter months, inside is a much different story. Inside the cocoon the caterpillar is going through metamorphosis. This is the chrysalis stage. The caterpillar bunches itself up and changes into a pupae. The pupae can still move although it doesn't even look alive. You can see characteristics of both the moth and the caterpillar in this pupae skin.
When spring arrives the moth hatches out of its pupae skin and exits the cocoon. The moth must climb up onto something in order for its wings to unfurl. At first the wings are tiny, but after 20 minutes to an hour they are fully developed. The moth gently moves them to promote circulation. The moth stage is the only time we see the insects gender. This also the time for reproduction. The male moth has big fluffy antenae which help him "smell" the female's scent. A male moth can sense a female from up to five miles away, given the wind is right. 
When the male and female find each other they mate, and the female lays the eggs. The female of this species mates only once, whereas the male may continue searching for additional females. Mating usually lasts 24 hours and the couple do not commute during this time.