Department of Integrative Biology
University of South Florida

Research in the Deban Lab is aimed at understanding the biomechanical and physiological mechanisms of how animals move and how these mechanisms change through evolution. We integrate biomechanics and physiology to understand the function of animal movement and to uncover general design principles. We also take an evolutionary approach in many of our projects, in addition to our studies of proximate mechanisms, so that we can gain insight into how present form and function came to be. The ultimate goal is to formulate broad principles about how complex systems evolve in the face of changing and conflicting functional demands, which is a key pursuit of evolutionary biology.
We are currently pursuing research on amphibian and reptile feeding and dog, lizard, amphibian and insect locomotion, among other projects.


High-Power Ballistic Movements

This photo of a Hydromantes shooting its tongue to catch a housefly reveals the spectacular performance of some ballistic movements. The tongue skeleton is acting like a harpoon and is shot completely from the salamander’s body. The tongue is projected so rapidly that it travels to the prey under its own momentum.

We are examining tongue projection as a model of ballistic movement and have found that tongue projection in salamanders is accomplished with extremely high power output via an elastic “bow and arrow” mechanism. Also, we have found that high power, ballistic tongues have evolved at least three times independently among the lungless salamanders. We are currently working to determine the physiological and biomechanical basis for this remarkably high performance. In addition, we are examining ballistic tongues of frogs and chameleons, which have evolved elastically powered tongues independently from those of salamanders and have different mechanisms. A central technique we use is capturing movements in slow motion to reveal details of their dynamics.


Limb-Trunk Integration in Running Tetrapods

Collaborative research we are engaged in focuses on how locomotor forces are generated in the limbs and trunk during running, and how this has changed in tetrapod evolution. Because the trunk muscles have both locomotor and postural roles, as well as respiratory functions in amniotes, conflicts can arise during locomotion. We are investigating how locomotor-ventilatory conflicts and locomotor-postural conflicts have been resolved in vertebrate evolution. We use a technique in which the muscles act as force transducers: we record changes in muscle activity as we manipulate locomotor forces by altering the environment or applying perturbations to dogs, lizards, and salamanders as they locomote. We have several recent publications from this research on dogs and salamanders of the genus Ambystoma.

 

Feeding in Tiny Tadpoles 

Our work on feeding in tiny tadpoles demonstrates the influence of body size on the biomechanical options available to aquatic organisms. As aquatic animals become very small they must adopt different biomechanics to feed and locomote. Tadpoles of the frog genus Hymenochirus became smaller through evolution and abandoned the ancestral mode of suspension feeding to become suction-feeding predators on relatively large prey. In the process they converged in function to a remarkable degree with teleost fishes.