Magnified 1197x, this 2006 scanning electron micrograph (SEM) depicted an enlarged view of the chitinous, exoskeletal surface of a male louse, Pediculus humanus var. corporis. In this particular view, the exoskeletal adornments are few, consisting of small, spike-like structures and a number of setae, or sensorial 'hairs'. Quite often the shape and size of these skeletal adnexae are quite complex, with forms following functions, which are just as varied. The exoskeleton is composed of chitin, a molecule made up of bound units of acetylglucosamine, which is joined in such a way as to allow for increased points at which hydrogen bonding can occur. In this way chitin provides increased strength, and durability as an exoskeletal foundation.
CDC/ Joseph Strycharz, Ph.D.; Kyong Sup Yoon, Ph.D.; Frank Collins, Ph.D.
November 2, 2012