Cuticle formation and pigmentation in beetles

Curr Opin Insect Sci. 2016 Oct:17:1-9. doi: 10.1016/j.cois.2016.05.004. Epub 2016 May 12.


Adult beetles (Coleoptera) are covered primarily by a hard exoskeleton or cuticle. For example, the beetle elytron is a cuticle-rich highly modified forewing structure that shields the underlying hindwing and dorsal body surface from a variety of harmful environmental factors by acting as an armor plate. The elytron comes in a variety of colors and shapes depending on the coleopteran species. As in many other insect species, the cuticular tanning pathway begins with tyrosine and is responsible for production of a variety of melanin-like and other types of pigments. Tanning metabolism involves quinones and quinone methides, which also act as protein cross-linking agents for cuticle sclerotization. Electron microscopic analyses of rigid cuticles of the red flour beetle, Tribolium castaneum, have revealed not only numerous horizontal chitin-protein laminae but also vertically oriented columnar structures called pore canal fibers. This structural architecture together with tyrosine metabolism for cuticle tanning is likely to contribute to the rigidity and coloration of the beetle exoskeleton.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Chitin / metabolism
  • Insect Proteins / metabolism
  • Pigmentation / genetics*
  • Tribolium / growth & development
  • Tribolium / physiology*
  • Tribolium / ultrastructure


  • Insect Proteins
  • Chitin