Dr. Elio Challita, Harvard University Microbiotics Laboratory
Peeing one drop at a time: How and why sharpshooter insects use superpropulsion to catapult theirfluid excreta
Feeding and waste elimination are essential functions for living things. While the impact offeeding on animal form and function has been studied extensively since Darwin, how excretion shapesanimal behavior, size, and energy use remains largely unexplored. Here, we examine tiny sharpshooterinsects that feed solely on nutrient-poor xylem sap from plants. To eliminate their large-volume waste,these insects use droplet superpropulsion, where an elastic projectile can achieve higher velocity than theactuator by tuning the timing. We combined mathematical models, CFD simulations, and biophysicalexperiments to show the insects tune the frequency of their anal stylus to the natural frequency of theirsurface-tension-dominated drops. Our model shows that superpropulsion is energetically cheaper forthese tiny insects than forming jets, enabling them to survive on the extremely energy-limited xylem diet.The principles of superpropulsion outlined here can inform energy-efficient self-cleaning designs and softengines for ballistic motion.
Elio Challita is a Postdoctoral fellow at the Microrobotics Laboratory at Harvard, developing insect-scaled microrobots. He earned his Ph.D. in Bioengineering from Georgia Tech, where he worked with Saad Bhamla in the School of Chemical and Biomolecular Engineering. His research, driven by curiosity, primarily focuses on the physics of living systems and fluid dynamics. He focuses on uncovering the physical principles behind the fluid dynamics in ultrafast invertebrates, such as sharpshooter insects, slingshot spiders, and termites. Prior to his doctoral studies, Elio received his bachelor’s degree in mechanical engineering from the Lebanese American University and his Master’s degree from the University of Georgia.
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