Eco‐evolutionary implications for a possible contribution of cuticle hardening system in insect evolution and terrestrialisation

Previously we proposed one aspect of how insects could adapt to terrestrial environments during their evolution. The hypothesis is based on a theory that have evolved an insect-specific system for cuticle formation mediated by enzyme. This enzyme, multicopper oxidase-2 (MCO2), catalyses the oxidation catecholamines using molecular oxygen as acceptor electrons from substrates. A potential advantage this MCO2-mediated utilization abundant in atmosphere, which different case crustaceans (close relatives insects) utilize calcium ions. Accumulation ions leads increase weight, but lightweight without calcification might been critical factor enabling evolve flight first history Metazoa. Our also provides simple explanation long-standing question why are so rare marine environments. In previous reviews, mainly focused details biochemical processes occurring arthropod cuticles, here only essence our extracted and briefly summarized with newly added information.