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General Research Interests

My lab focuses on the origin and evolution of innovations, integration, and complexity, with a strong emphasis on the ecological context of organismal function. To do this, we integrate comparative physiology, biomechanics, comparative evolutionary methods, genomics, and ecology. This naturally combines organismal approaches with sophisticated laboratory techniques (see below). We also utilize museum collections across the world, including those at the Museum Koenig (Bonn, Germany), the LA County Museum, the California Academy of Sciences, and others. Examples of research projects include the functional and evolutionary consequences of gaining and losing adhesion among geckos, the evolutionary integration of feeding and locomotion among fishes and snakes, the neuromuscular basis of locomotion among anoles and geckos, the genetic architecture of biomechanical traits in threespine stickleback, and the evolution of vision in geckos. Our fieldwork is conducted in a number of places, including the Bamfield Marine Sciences Centre in British Columbia, Gobabeb Research & Training Centre in Namibia, Nouragues in French Guiana, South Africa, and Trinidad & Tobago. We also have research plans in Mexico and Alberta, Canada

Examples of recent research projects:

• Muscle dynamics and biomechanics of locomotion among lizards (see publications 36, 42, 69, & 81)
• Biomechanics and the origin of species: predator-prey interactions in fishes (see publication 66)
• The morphology and ecology of the adhesive apparatus of geckos (see publications 52 & 57)
• The biomechanics and evolution of gecko locomotion (see publications 48, 52, & 53)
• The ecomechanics and integration of locomotion and feeding in fishes (see publications 58-60)
• Functional complexity within and among muscles during locomotion (see publications 28-29)
• The neurobiology and biomechanics of tail autotomy in lizards (see publications 40, 49, 74, & 81)
• Hydrodynamics and biomechanics of suction feeding in fishes (see publications 55 & 59)

Experimental Techniques

• Scanning Electron Microscopy and 3D analyses (SEM): This technique allows allows us to quantify the microtopography of both gecko adhesive surfaces and the surfaces on which they move. We then use the SEM module in the MountainsMap software package to quantify the 3D surface topography from multiple SEM images.
• Electromyography (EMG): This technique allows one to measure the electrical activity in a muscle using indwelling electrodes. I use this to quantify the intensity and timing of activation patterns during dynamic locomotion
• Sonomicrometry: This technique utilizes ultrasonic pulses between piezoelectric crystals to measure distances in real time. For example, I implant these into muscles to measure the changes in length along a fascicle.
• Aurora in situ/in vitro muscle lever system: I use this system to examine force-length and force-velocity properties of muscles. By combining this with in vivo measurements, I am able to determine how muscles operate in relation to their capabilities.
• Digital particle image velocimetry (DPIV): This is a modern computational technique that permits the visualization of fluid movement. I use this to determine flow patterns during suction feeding in fishes.
• High-speed digital video: I use a pair of Photron APX-RS cameras, a pair of Phantom Miro M110 cameras (capable of filming 250,000 images/second), and a pair of Edgertronic cameras (sensitive to IR) to quantify three-dimensional high-speed movements during locomotion and prey capture.
• In vivo pressure recordings: By surgically implanting pressure transducers into the mouth (buccal) cavities of fishes, I quantify the pressure within the buccal cavity relative to the surrounding fluid during suction feeding in fishes.
• Force plates: I use a custom built force plate (from 6 axis force-torque sensors) to quantify the mechanics of terrestrial locomotion in birds and lizards. This involves inverse dynamics and center of mass mechanics, and I study animals from 3kg down to 2g.