Screening for scorpions: A non-invasive approach to tracking the movements of arachnids in sand

Piezoelectric materials are highly sensitive devices capable of transducing mechanical energy into electric voltage. They find application as sensors in a wide variety of commercial and academic fields. Borrowing from the use of these materials in geophysics to measure the transmittance of a wave front through a substrate, and the principles used to locate the epicenter of an earthquake, we used an array of piezoelectric transducers on a much smaller scale to triangulate the position of a scorpion, in sand, as it leaves its burrow to hunt. Such an approach relies on the ability to resolve the surface waves created by a scorpion’s footsteps and uniquely identify them against a background of other such waves. Such a passive form of measurement has the benefit of eliminating environmental factors associated with other monitoring systems, such as camera lights, that could change the scorpion’s behavior. The work to date has yet to yield a fully functional tracking system but has identified the major obstacles that, when resolved, should yield a sensitive, accurate, and dependable technique. Much progress has been made in resolving issues of sensitivity and reproducibility of signal measurement with the piezoelectric materials currently in use.