Crustacean Molting: Regulation and Effects of Environmental Toxicants

In crustaceans the growth of the animal occurs by shedding of old exoskeleton and formation of new exoskeleton. Immediately after ecdysis the newly synthesized cuticle up takes water to expand new exoskeleton thereby size. Molt cycle in crustaceans is under the control of several regulatory hormones, internal and external factors. The predominant hormones molt inhibiting hormone (MIH) and ecdysteroids act in a controversy manner to one another in regulation of molt. It is also identified that the methyl farnesoate (MF) induces molting by inducing the synthesis and release of ecdysteroids from Y-organs. Besides several other hormones and internal molecules like opioids and neurotransmitters along with toxicants (xenobiotics, chemicals and metals) are also involved in the regulation of crustacean molting. Toxicity of aquatic pollutants leads to retardation of growth and delays molting, besides influence mortality and causes huge loss to crustacean farming. This review presents the advances in the field of crustacean molting and its regulation.