Caterpillars, like all insects and arachnids, have an exoskeleton made of chitin. Exoskeletons are hard but not very flexible, so a caterpillar that is still growing has to shed its old skin to make room for a larger one. When it’s ready, the caterpillar grows a new skin underneath the old one, then sheds the skin that was keeping it from growing any larger. This process is more commonly called MOLTING.
The molting process begins with the fluid being pumped into the new skin under the old one. The newly-formed skin starts to separate from the old skin and soon splits open along the back end of the caterpillar. After this split opens, it’s only a matter of time before the caterpillar can wriggle out of its old skin and emerge as a new, larger version of itself.
It takes a while for a caterpillar to pump up its new exoskeleton with fluids before it can molt. Because of this delayed time between molts, you can often see dark lines running down some caterpillars‘ sides — these lines are actually spaces between previously-molted skins that were stretched out by growth.
Why do caterpillars shed their skin?
All caterpillars shed their skin as they grow larger. This is called molting. Unlike humans, caterpillars do not get taller as they grow; instead, they get fatter.
When a caterpillar outgrows its skin, it needs to shed the old skin and form a new one, much like it would if it had grown out of clothes that are now too small.
The process of molting is known as ecdysis. Molting is simply the shedding of an old layer of skin or exoskeleton to reveal a new one.
Caterpillars molt anywhere from four to six times before they turn into pupae. Each time they shed their skin, they grow bigger and bigger. They must shed their skin every time because their skin cannot stretch to accommodate their growing bodies.
Do monarch caterpillars shed their skin?
Monarch caterpillars shed their skin as they grow. They do this about five times during their caterpillar stage.
The first time a Monarch caterpillar sheds its skin is after it hatches from its egg. It is called the exuviation, or ecdysis, process. It occurs when a new, larger skin has formed underneath the old one and then splits open to reveal the new skin underneath.
After this first shedding of skin, the Monarch caterpillar will shed its skin another four times before it is ready to pupate. During each of these four instars, or stages between ecdysis, the Monarch caterpillar will eat voraciously to fuel its incredible growth.
Do peacock caterpillars shed their skin?
Yes, peacock caterpillars do shed their skin. They usually shed their skin before the ecdysis cycle. The ecdysis cycle is when they molt and become bigger in size.
When a peacock caterpillar first hatches from its egg, it is very small and only has two or three pairs of legs. The rest of its legs will grow as the caterpillar sheds its exoskeleton and grows in size. By the time it is ready to become a butterfly, it will have six pairs of legs like all other insects.
Do caterpillars eat their shed skin?
Caterpillars molt several times during their development, and they eat the skin they shed. In fact, they even eat their old feces, which are called frass. They are able to do this because caterpillars’ digestive systems are designed to break down plant matter, which is made up of tough cellulose fibers.
The process of eating their old skin and frass does not help caterpillars directly because it only provides them with a small amount of nutrients. However, it helps them indirectly by keeping the area around them clean of evidence that might attract predators and parasites.
How often do caterpillars shed their skin?
Most caterpillars shed their skin four or five times before they’re big enough to pupate. Sometimes they shed their skins more often and sometimes less often, but, on average, they molt around five times.
Before a caterpillar sheds its skin, it makes an enzyme that will dissolve the glue between its old skin and its new skin. Then it slowly pushes itself out of the old skin by stretching its body slightly. The old skin then comes off over the caterpillar’s body like a sock.
Thus, caterpillars molt because they outgrow their old, inflexible exoskeletons. The shed skin is usually eaten by other caterpillars, and a particular species of moth can even use its shed skin as a disguise to protect it while it rests during the day.