Editing Ecdysis (section)

==Insects==
{{wide image|Aeshna cyanea freshly slipped L2.jpg|1200px|Moulting (ecdysis) in [[southern hawker]], ''Aeshna cyanea''}}

Each stage of development between moults for insects in the taxon [[Endopterygota]] is called an [[instar]], or stadium, and each stage between moults of insects in the [[Exopterygota]] is called a nymph: there may be up to 15 nymphal stages. [[Endopterygota]] tend to have only four or five instars. Endopterygotes have more alternatives to moulting, such as expansion of the cuticle and collapse of air sacs to allow growth of internal organs.

The process of moulting in insects begins with the separation of the cuticle from the underlying epidermal cells (apolysis) and ends with the shedding of the old cuticle (ecdysis). In many species it is initiated by an increase in the [[hormone]] [[ecdysone]]. This hormone causes:
* apolysis – the separation of the cuticle from the [[Squamous epithelium|epidermis]]
* [[secretion]] of new cuticle materials beneath the old
* degradation of the old cuticle

After apolysis the insect is known as a [[pharate]]. Moulting fluid is then secreted into the exuvial space between the old cuticle and the epidermis, this contains inactive enzymes which are activated only after the new [[epicuticle]] is secreted. This prevents the new [[procuticle]] from getting digested as it is laid down. The lower regions of the old cuticle, the [[endocuticle]] and [[mesocuticle]], are then digested by the enzymes and subsequently absorbed. The [[exocuticle]] and epicuticle resist digestion and are hence shed at ecdysis.