That footage revealed that the valves attached to each lancet—both of which sit inside the venom pumping chamber—change shape during pumping as they slide back and forth. They inflate like a parachute on the downstroke, creating a seal via a piston-like action that applies downward pressure in the chamber to push out the venom. They deflate on the upstroke. And the valves change their shape again when they meet in the middle in order to push past each other.
“The unique geometry of the valves is the key; they act as collapsible pistons and—by pumping in opposite directions—they’re able to deliver a continuous flow of venom,” said co-author Fiorella Ramirez-Esquivel of Macquarie University. “The double piston design adds complexity, but it’s the key to the stinger being able to deliver venom continuously in a compact, autonomous unit.” The dual motion also minimizes backflow.
Those results were consistent with the authors’ preliminary flow visualization experiments. To verify the initial findings, the team took micro-CT scans and used that data to create a 3D-printed scaled prototype model to mimic the observed pumping behavior. This pumping motion, too, was filmed and analyzed frame by frame. The artificial pumping model showed the same pumping kinematics as the biological stingers.
Future research may focus on a closer examination of the material properties of the valves, since the team’s artificial polymer valve shows extremely high elasticity is key to replicating the necessary valve deformations, along with low friction between the valves. It would also be useful to investigate whether capillary action plays a role, given the small size of the venom-pumping elements. Capillary action could help draw venom into the venom canal, or alternatively, the venom may need to counter capillary action working to draw fluid up from the tissue.
Prior research has used bee stinger structure as an inspiration for the design of microneedles, tissue transport devices, and drilling devices. The authors believe their own work will eventually find similar medical and microfluidic application, such as for artificial pumps.
DOI: PNAS, 2026. 10.1073/pnas.2603916123 (About DOIs).