Australian scientists have uncovered the mechanism that allows a honeybee's stinger to continue to pump venom after the bee flies away.
The breakthrough will be cold comfort to those who have had the misfortune of swiping at a stinging bee, only for the pain to continue.
But for the scientists at Macquarie University and University of New South Wales who helped crack the mystery, it was five years well spent.
"It's been a monumental effort," lead author of the study laying out the work, Fiorella Ramirez-Esquivel told AAP.
"Sometimes as scientists you don't get to dig in as far as you want to. But this one was a really good, meaty project."
Researchers have known honeybees empty their venom sacs into a chamber using small pumps since the early 20th century.
But the pioneering study, published in US scientific journal PNAS, is the first to expose, and film, how stingers continue to pump after they have come free.
Using high-speed video, Dr Ramirez-Esquivel revealed how two tiny, specially shaped valves act like pistons to continually pump venom.
The valves change shape to form a parachute-like seal during the downstroke and collapse to minimise back flow on the upstroke.
"The unique geometry of the valves is the key," Dr Ramirez-Esquivel said.
"They act as collapsible pistons and - by pumping in opposite directions - they're able to deliver a continuous flow of venom."
The authors hope the design, which they replicated on a 3D printed model, could have applications for medical technologies.
"People have suggested to us that it could be useful in designing something like an insulin pump," Dr Ramirez-Esquivel said.
The work was finicky and, at times, grim - from capturing the insects, to pulling their stingers free using forceps.
"I only got stung one time when I was trying to catch bees outside," Dr Ramirez-Esquivel said.
"I missed with my little jar, and she got a bit upset with me, which is very fair."