The exoskeleton of insects functions as both skin and supporting skeleton. It is formed from a material called cuticle, composed of proteins and a carbohydrate (chitin), and simple organic compounds known as catechols. Despite this limited compositional palette, cuticle has remarkably diverse properties, ranging from soft and flexible to hard and rigid. It is quite strong, but it is lightweight compared with bone of vertebrate animals, because cuticle lacks mineral components. The mechanical properties of insect exoskeleton have certainly contributed to the overwhelming success of insects in adapting to nearly every habitat and in their development of the ability to fly. This proposal describes experiments to investigate the biochemical compounds and chemical reactions that form insect cuticle and to understand how these result in cuticular regions with differing mechanical properties. This interdisciplinary project, involving biochemists and engineers, makes use of the red flour beetle, Tribolium castaneum, as a model organism to investigate the relationships of cuticle protein properties and chemistry with the development of rigid cuticle. The proposed approaches combine molecular and mechanical analysis to yield advances in fundamental understanding of cuticle biochemistry and development of potentially useful new materials based on cuticle chemistry. Broader impacts resulting from the research will include education and training for undergraduate and graduate students. Specific efforts at broadening opportunities for participation in science will include research experiences by diverse undergraduate students and outreach to middle school and high school students. Advances in understanding of this critical physiological system in insects will lead to a deeper knowledge of insect biology will aid in producing new types of cross-linked biopolymers based on the chemistry of cuticle. This new class of 'bioinspired' materials has potential technological applications in medicine, pharmacy and agriculture.
