Rachel L. Crane, Ph.D.

Biomechanics and Behavior of

Predator-Prey Interactions

Evasive prey and high-speed chases

3D aerial pursuit by dragonflies

Dragonflies are remarkable predators, zipping through the air to capture erratic and evasive prey with up to 95% success. They are also generalist predators, capable of efficiently capturing prey that differ in flight and sensory capabilities. For specialist predators that target only a single prey type, adopting a highly specialized strategy may provide advantage. On the other hand, generalists predators, like dragonflies, that contend with different prey may benefit from the ability to adjust their predation strategy.

Rachel studies how dragonflies adjust their pursuit strategies to account for prey flight kinematics and behavior. She is interested in how they balance trade-offs in capture success and the energetic cost of pursuit. Dragonflies are an ideal system to answer fundamental questions about 3D aerial pursuit and evasion.

Armored prey and armor-breaking predators

Fatigue and repair of bivalve shells

Animals’ shells defend them from a variety of environmental dangers and predatory attacks, including a multitude of low-magnitude, repeated stresses, which cumulatively cause lethal fatigue damage. She studies how shell features—from composition and microstructure to overall morphology—contribute to fatigue resistance, as well as how animals respond to and repair accumulating shell damage. By developing new mechanical techniques to test shell fatigue resistance and animal responses to damage, she answers questions about the ecological interactions between hard-shelled mollusks, their predators, and the environment.

Crane, R.L. & Denny, M.W. 2022. Bivalves maintain repair when faced with chronically repeated mechanical stress. J. Exp. Biol. jeb243813.

Crane, R.L., Diaz Reyes, J.L.*, & Denny, M.W. 2021. Bivalves rapidly repair shell damage from fatigue and bolster strength. J. Exp. Biol. jeb242681.

Crane, R.L. & Denny, M.W. 2020. Mechanical fatigue fractures bivalve shells. J. Exp. Biol. 223. jeb220277.

Mantis shrimp behavioral strategy

Working in Sheila Patek's lab, Rachel studied how mantis shrimp (Stomatopoda) manipulate prey. Mantis shrimp possess a specialized front appendage to smash and fracture hard-shelled prey at accelerations up to 1.5x105 m/s2 and speeds up to 30 m/s. Research on predation by mantis shrimp often focuses on how impressive this strike is. However, mantis shrimp can require hundreds of strikes to crack a snail shell sufficiently to obtain food.

Rachel's research has shown that these strikes are carefully targeted to efficiently crack open the shell, and that mantis shrimp change strategy depending on shell shape. Mantis shrimp predation success relies not just on a powerful weapon, but also on the behavioral flexibility to use it effectively with different prey.

Crane, R.L., Cox, S.M., Kisare, S.A.*, & Patek, S.N. 2018. Smashing mantis shrimp strategically impact shells. J. Exp. Biol. 221. jeb176099.