Viscoelastic liquid lassos extend the defensive reach of termite soldiers
Small animals face a severe size asymmetry when defending themselves against larger predators. Soldiers of Nasutitermes termites overcome this constraint by ejecting tens of nanoliters of secretion through a cephalic nozzle, the nasus. High-speed imaging in the field, rheometry, micro-CT, flow simulation, behavioral assays, and scaled experiments reveal a multistage defense. A near-linear nasus and shear-thinning secretion support rapid ejection. Lateral head oscillation at 5-30 Hz couples with rope-coiling instability to distribute the filament as loops and meanders, a ``liquid lasso,'' reaching up to three body lengths. After deposition, the apparent extensional viscosity increases 8- 80-fold, delaying breakup as the secretion cures into a persistent adhesive. The lasso coats the sensory and grooming structures of predatory ants, and tethers them to the substrate. Synthetic experiments show that nozzle geometry, orientation, height, and oscillatory motion jointly control ejection and coverage, providing design principles for deploying small volumes of time-evolving viscoelastic materials.