Insect Physiology - Molting


As an insect grows it needs to replace the rigid exoskeleton regularly (McGavin 2001; Triplehorn & Johnson, 2005,). Molting may occur up to three or four times or, in some insects, fifty times or more during its life (McGavin, 2001). A complex process controlled by hormones, it includes the cuticle of the body wall, the cuticular lining of the tracheae, foregut, hindgut and endoskeletal structures (McGavin 2001; Triplehorn & Johnson, 2005).

The stages of molting:

  1. Apolysis—molting hormones are released into the haemolymph and the old cuticle separates from the underlying epidermal cells. The epidermis increases in size due to mitosis and then the new cuticle is produced. Enzymes secreted by the epidermal cells digest the old endocuticle, not affecting the old sclerotised exocuticle.
  2. Ecdysis—this begins with the splitting of the old cuticle, usually starting in the midline of the thorax’s dorsal side. The rupturing force is mostly from haemolymph pressure that has been forced into thorax by abdominal muscle contractions caused by the insect swallowing air or water. After this the insect wriggles out of the old cuticle.
  3. Sclerotisation—after emergence the new cuticle is soft and this a particularly vulnerable time for the insect as its hard protective coating is missing. After an hour or two the exocuticle hardens and darkens. The wings expand by the force of haemolymph into the wing veins (McGavin, 2001; Triplehorn & Johnson, 2005).

Read more about this topic:  Insect Physiology

Other articles related to "molting":

Confuciusornis - Paleobiology - Sexual Variation
... lack tail feathers because they were fossilized during molting ... As in modern birds, molting individuals may have been present alongside non-molting individuals, and males and females may have molted at different times during the year ...
Ghost-faced Bat - Description
... This particular bat undergoes molting, usually between June and September ... On the dorsal side, molting starts on the shoulders and spreads over the back, whereas on the ventral side molting usually begins under the wings, on the neck and chin and then ...
Prothoracicotropic Hormone
... of the head of immature insects could prevent molting or pupation of the body region excluded from the head if the ligation was performed before a critical age in the lifestage was reached ... abdomen or an abdomen under diapause would induce molting or pupation ... thought to be the source of the hormone that induces molting in insects ...
Terrance Zdunich - Career
... began work on a solo project, a comic book series dubbed The Molting ... The Molting, which is being published independently, is expected to be released in 12 parts ... his artistic process in a blog series entitled “Molting with the Molting.” As of April 2011, six chapters have been published Guilty Susie, The Happiest Place on Earth, Ootheca, Lethal Raids, Mother’s ...
Sarcoptes Scabiei - Life-cycle
... the 6-legged larvae migrate to the skin surface and then burrow into molting pouches (these are shorter and smaller than the adult burrows) ... Adult mites then mate when the male penetrates the molting pouch of the female ... The impregnated female then leaves the molting pouch in search of a suitable location for a permanent burrow ...