Bumblebees can breathe underwater by surrounding themselves with an air pocket that acts like a diving bell, scientists believe.
The discovery comes after researchers accidentally flooded a laboratory fridge and realised bees could survive submersion in water for several days.
But until now it was a mystery as to how the flying insects managed to survive the mishap.
Now a team at the University of Ottawa has found that bumblebees breathe underwater using a kind of artificial gill.
Researchers submerged queen bees in water in test tubes and measured the oxygen and carbon dioxide levels.
Analysis of the amount of oxygen and carbon dioxide suggested the bees were somehow managing to take the oxygen out of the water.
Experts now think that the queen traps a bubble of air around herself and breathes in the oxygen using tiny tubes on her abdomen called spiracles.
As the oxygen depletes in the air bubble, more is pulled in from the water outside through diffusion, while carbon dioxide is expelled.
This bubble technique is known as physical gill and it is used by several insects for breathing underwater.
“We now know they exchange gases,” said Professor Charles Darveau, of the Department of Biology at the University of Ottawa.
“It appears substantial enough that they likely need what’s called a physical gill: air trapped at the surface of the animal, which they can use to breathe through their tracheal system and replenish oxygen from the water.”
Scientists originally thought that the bumblebee queens may have closed their breathing holes and relied on air left inside their body to survive.
But the experiments showed that they were actually using oxygen in the water.
Scientists think that bees may have evolved the technique to avoid dying if the ground becomes flooded while they are hibernating beneath the surface.
The technique of using an air pocket to allow breathing underwater is used most effectively by the “diving bell spider” which spins a dome shaped web balloon and then fills it with air bubbles.
When it is large enough to get inside, the spider uses it as a little submarine to embark on underwater hunting trips and also lays its eggs inside.
Diving beetles, water boatmen, backswimmers and some semi-aquatic lizards also carry a bubble of air under their wings or bodies to help them breathe underwater.
Experts said it was encouraging to know that if flooding events increase in the future, because of climate change, bumblebee queen populations would be able to survive.
The research was published in the journal Proceedings of the Royal Society B: Biological Sciences.