Why Beetles Have Hard Elytra

Red Flour Beetle

Red Flour Beetle

Beetles have hard forewings called elytra that protect the more delicate membranous hind wings used for flight. Scientists interested in cuticle structure* have examined cuticle from the elytra of the red flour beetle, Tribolium castaneum. The elytra have two proteins in large amounts that are not present in the membranous hindwings. These proteins are associated with hard cuticle both in the elytra and elsewhere on the beetle. The cuticle of the elytra becomes hard and rigid from extensive crosslinking, or chemical connections between the protein strands. This evidence from red flour beetle suggests that in the evolutionary past, an ancestor of modern beetles had a mutation caused proteins for cuticle crosslinking to be expressed in the forewings. The up regulation of two cuticle genes in the forewings may be a key to the evolution of elytra.

*Mi Young Noh, Karl J. Kramer, Subbaratnam Muthukrishnan, Michael R. Kanost, Richard W. Beeman, Yasuyuki Arakane. Two major cuticular proteins are required for assembly of horizontal laminae and vertical pore canals in rigid cuticle of Tribolium castaneum. Insect Biochemistry and Molecular Biology. 53: 22-29.
http://dx.doi.org/10.1016/j.ibmb.2014.07.005.

About jjneal

Jonathan Neal is an Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in Biomaterials, by jjneal, Taxonomy. Bookmark the permalink.

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