The viscoelastic spit of termite soldiers

Termite soldiers (Termitidae, Nasutitermitinae) spit viscoelastic jets through their nozzle-shaped heads to defend their mounds from predators (ants). Here, we uncover their lasso-like jets' fluid dynamics and rapid ejection mechanism (max velocity ~ 0.4 m/s, spit time ~250 ms). Using high-speed imaging and field experiments in the Amazonian rainforest, we uncover the rheological properties and the dynamic instabilities of these volatile jets in the air. Using scaling analysis and mathematical modeling, we demonstrate how these insects exploit lateral head movement to form large viscoelastic lassos (~ 2x body length), possibly enabling them to entangle their larger predators. We analyze the effect of the geometry of the conical nozzle of three species of termites on the kinematic output of their jets. Understanding the fluid mechanics of these microjets helps uncover the biophysical limits of the termite's defensive behavior and helps inform the design of jet extrusion nozzles at the microscale.