Study reveals how honeybee stinger pumps venom

Researchers have recorded how two shape-changing valves in a honeybee’s stinger work together to pump venom continuously, revealing the mechanism behind a process scientists have studied for more than a century. The team used high-speed video to observe the stinger’s pumping cycle and reported that the valves act as collapsible pistons, sealing to push venom and collapsing to refill. The study, led by Fiorella Ramírez-Esquivel of Macquarie University with researchers from the University of New South Wales, was published in the Proceedings of the National Academy of Sciences. The researchers also used microCT scans to examine the stinger’s structure and built a 3D-printed model that reproduced key features of the pumping mechanism. In the researchers’ account, each valve changes shape during the pumping cycle. On a pressure stroke, it expands against the wall of the chamber to form a seal and push venom forward. As it returns, it collapses, allowing the chamber to refill while limiting backflow. The valves work in opposite directions, so one can push fluid as the other refills, supporting continuous flow.