High-Speed Video Reveals Honey Bee Stinger's Double-Piston Venom Pump

Honey bees (Apis mellifera) are known to leave their stingers embedded in flesh when they sting and then fly away. The stinger continues to penetrate tissue and pump venom on its own, a rare phenomenon known as autotomy. The new paper says scientists have now determined how that continued pumping works: the stinger uses a double-piston pump-like mechanism.

Different species have evolved different ways to deliver venom. The process generally involves piercing the skin and then pumping venom from a gland or reservoir. Spiders have muscles surrounding their venom glands; those muscles contract and eject venom through hollow fangs. Bees, wasps, and ants deliver venom through their stingers, either by contracting muscles around the venom reservoir or through stiff elements called lancets working together to pump venom.

Honey bees add a feature not seen in those other systems. Worker bees fly away after inserting their stingers into a target, leaving the stinger behind. The stinger then continues to penetrate tissue and pump venom on its own.

A honey bee’s stinger has three main interlocking elements that form the venom canal. One is a stylet that widens to form the main pumping chamber. The other two are sharp-tipped lancets that slide back and forth, piercing tissue and pumping venom into the target. Until now, the precise mechanism by which the pumping action is achieved had never been directly observed, according to the paper.

The new paper reports that high-speed video captured the process and identified the double-piston pump-like mechanism. The finding is published in the Proceedings of the National Academy of Sciences.