Molting



Molting is an essential part of growth for many organisms, such as insects and [reptiles]]. The frequency of the process is ultimately determined by growth rate and is mediated by hormones. Organisms, such as Arthropods, have rigid exoskeletons and cannot grow bigger until they shed their shell. Growth instead occurs between each molt during a lifecycle stage called an instar.

Hormone mediation

 * Main Article: Endocrine system

There are two kinds of hormones working in sequence that regulate molting – brain hormone and ecdysone. Brain hormone is transported to and sorted in the corpora cardiaca, a pair of structures attached to the brain. When the corpora cardiaca releases brain hormone, it diffuses to the prothoracic gland. Then, the prothoracic gland is stimulated and releases ecdysone. This hormone diffuses to target tissues and stimulates molting.

Arthropod ecdysis
Arthropods, such as lobsters, will molt periodically depending on their rate of growth. The molting process in arthropods is known as ecdysis. One of the first physical signs of molting is the release of fluid from a multitude of “molting” glands. At first the tail will crack open, very slightly. While different hormones trigger different stages around the lobsters body, the crack opens even more. Then the lobster slowly wiggles it’s body form the old shell in about 8-12 hours. The lobster will then go through a rapid growth period until its new shell hardens.

Molting in a trap: Due to a speculated reason, lobsters will begin the molting process with the thorax while in a fishing trap with other lobsters.

Reptile shedding


The skin-shedding process in reptiles is also called molting. Before molting, snakes such as pythons will be less active than usual. The eyes will eventually become clouded or a whitish color because the skin covering the eyes is shed along with the rest of the body. Snakes will loosens the skin around their mouth and head by rubbing its nose on a rough surface. They then crawls out of the old skin, turning it inside out in the process.

Snake molting dependent on its age and how active it is. Young snakes shed more often than older ones do. Those that live in warm climate areas are active for longer periods than those that live in cooler climates. As a result, they molt more often. Some tropical snakes shed six or more times a year do to the climate.