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Ph.D. Candidate - Department of Biology
University of North Carolina at Chapel Hill
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Biomechanics | Behavior | Form and Function
Research
Locomotion comes from the organization, physiology, and biomechanical properties of the body structures (muscles and skeletons), and their coordinated response to the environment. I am interested in understanding how animals move through, and interact with their environment, modifying their behavior according to the available resources, and how their body structures respond to environmental and intrinsic changes.
Photo by Iris Reed
Harvesting energy from the wind
​Black skimmers (Rynchops niger) feed in a unique way, called skimming, with their mandible in water as they fly over a food (fish) patch experiencing increased flight costs. However, their coastal environment with strong winds could be exploited to reduce these costs. We investigated if skimmers are extracting energy for foraging from the wind gradient by strategically using the wind direction, using field video recordings of naturally behaving skimmers in the North Carolina coast.
Foraging in high-risk environments
Barns swallows (Hirundo rustica) are fast and highly maneuverable flyers that feed on insects close to the ground, and occasionally over water. They relay on their speed to be able to catch their prey, however foraging over water introduces the risk of increasing the transport cost by getting wet. We investigated the flight strategy used by barn swallows as they approach the water surface while foraging in their natural environment.
Photo by Jonathan Rader
Bird aquatic take-off
Among the most expensive movements for flying birds is take-off: the action of going from rest to an explosive jump (on land) followed by wing motion to keep the animal in the air. However, many aquatic birds also take-off from water which introduces additional challenges given the physical properties of water (higher density and viscosity). We characterized the take-off strategy of phylogenetically diverse aquatic bird species to understand how body size and shape influence on the movement for freely behaving birds.
Speed and force necessary for aquatic take-off
The webbed feet of birds help them navigate the aquatic environment. Many aquatic birds use their feet to initiate take-off from water leaping out of water. We built a mechanical model of bird webbed feet of different sizes to quantify the speed and force required to leave the water surface depending on body and muscle mass.
Photo by Jonathan Rader
Human muscle architecture during different contractions
Form-function relationships of muscle are particularly interesting in the pennate structure. The contraction of a pennate muscle leads to a shape shift with muscle fibers shortening, muscles thickening, and fiber angle (pennation angle) increasing. We explored the relationship between muscle architecture and force production using ultrasound images in-vivo of the gastrocnemius muscles of human participants performing isometric and isotonic contractions.
Flight muscle-body size scale in social wasps
Insect flight is the product of directly and indirectly attaching muscles that move and control the wings. Wasps have an incredible distribution of body and wing sizes, and equally diverse foraging behaviors. To explore if the body structure of wasps dictates and limits their behavior, we studied the muscular structure of the flight muscles of four wasp species by performing thorax dissections and polarized light microscopy (Laboratorio de Microscopia Óptica, Universidad Nacional de Colombia), and measuring muscle insertion points, muscle area, fiber length, and sarcomere length.