Faculty

David E. Alexander - Entomology, Biomechanics and Animal Flight
Assistant Professor
Ph.D., Duke University
6008 Haworth Hall
Phone: (785) 864-3370

Classes Taught

Biol 120: To Know a Bug: Insects in Your World
Biol 240: Basic Human Anatomy
Biol 246: Principles of Human Physiology
Biol 644: Comparative Animal Physiology
Biol 646: Mammalian Physiology

Area of Interest and Research

My general area of interest is biomechanics, which uses engineering techniques and approaches to study the physical properties of organisms, and the interactions between organisms and their physical environment.

I am particularly interested in studying ways in which flying animals achieve similar results to airplanes, using fundamentally different mechanisms, such as for maneuvering or lift augmentation. For example, I have used high speed cinematography to study wing movements that produce turns by flying dragonflies. Students in my lab are investigating aerodynamic effects of wing architecture and stabilizing mechanisms of flying insects.

I also study arthropod swimming mechanics and energetics. I would like to link the internal energetics (respiration) with the external energetics (work and power output) of swimming. This would allow us to evaluate the swimming efficiency of animals. These studies include observations of locomotion and experiments using high speed cinematography and force measurements, fluid mechanical analyses and computer modeling, and gas exchange measurements and energetic analyses. These studies will help answer such questions as: What are the mechanical and physiological constraints on swimming arthropods? What arthropod swimming modes are most efficient, and how do they compare to other swimming animals?

I have recently become interested in empirical methods to measure stability, and in addition to flight stability we are studying stability in swimming. We have also developed techniques to measure the mechanical properties of very small structures, and students have used these techniques to study the stiffness of swimming appendages in small crustaceans and cuticle strength in caterpillars.

Representative Publications

Alexander, D. E. 2002. Nature's Flyers: Birds Insects and the Biomechanics of Flight. Johns Hopkins University Press, Baltimore. 358 pp.

Alexander, D.E. 1990. Drag coefficients of swimming animals: effects of using different reference areas. Biological Bulletin 179: 186-190.

De Souza, M.M. & Alexander, D.E. 1997. Passive aerodynamic stabilization by beetle elytra (wingcovers). Physiological Entomology 22:109-115.

Alexander, D.E. 1986. Wind tunnel studies of turns by flying dragonflies. J. Experimental Biology 122: 81-98.

Alexander, D.E., J. Blodig, and S.-Y. Hsieh. 1995. Relationship between functional and mechanical properties of the pleopods of isopod crustaceans. Invertebrate Biology 114: 169-179.