Rapid-fire trap-jaw ants, exploding dogwood flowers, ballistic amphibian tongues and the cellular spears of jellyfish produce extremely rapid movements through the simple physical principle of power amplification: the amplification of work relative to time, such that the duration of movement is decreased as speed and acceleration are increased. For the past forty years, power amplification has been the guiding physical principle in understanding fast movement in biology. However, most studies to date have focused on solving the intriguing biomechanics of single species and notably little is known about the evolutionary processes and patterns underlying the diversification of power-amplified systems. This proposal has two primary goals: (1) to examine and test the broad, unifying principles that underlie rapid movements in biology and (2) to establish and implement a quantitative framework for understanding the evolutionary dynamics of biomechanical diversification. To address these goals, the evolution and biomechanics of power amplification will be studied in mantis shrimp (Stomatopoda) which generate among the fastest and most forceful predatory movements in the animal kingdom. These impressive movements are controlled by slowly contracting muscles that activate a network of power amplification structures including springs, latches, linkages and lever arms. This power amplification system is conserved across the 450+ species of stomatopods, yet their raptorial appendages exhibit remarkable diversity ranging from spiny and barbed spears to hatchets and hammers. Power amplification will be examined from two perspectives. The first aim is to probe how the components of power-amplified systems vary to achieve different outputs. Spring material and mechanical testing will be performed, a mathematical model will be used to measure the effects of variation in loading regimes, energy transmission and drag, and a physical model will be used to examine the energetic costs and benefits of fluid dynamic forces and cavitation. The second aim is to ask how a balance of biomechanical integration and macroevolutionary variability is achieved, specifically by testing how key parameters of power amplification mechanisms are varied over time while still maintaining a cohesive, functional mechanical system. The culmination of this research will be a quantitative, evolutionary analysis of the dynamic interplay between the fundamental physical principles of power amplification and the evolutionary diversification of rapid biological movements. The Educational Plan includes discovery and training at multiple levels, ranging from high school to postdoctoral. Hands-on training in interdisciplinary, computational and field research will involve undergraduates, graduate students and postdoctoral scholars. A new undergraduate-level course will incorporate physics, engineering, computational and evolution-based approaches to organismal movement. An existing program founded by the Principal Investigator (PI), which has generated over 200 undergraduate research experiences in biology laboratories over the past two years at UMass Amherst, will be expanded to include a second program to match UMass undergraduates with interdisciplinary research opportunities outside of their degree-granting departments. A Research Experience for Teachers program will be established in the UMass Biology department through this grant; each summer, a high school teacher will conduct research in the PI?s laboratory leading to a presentation at a regional conference, a photo-documentary of the experience, and the development of inquiry-based classroom materials that conform to state standards.
