Honey bees are known to leave their stingers embedded in tender flesh once they sting you and fly away. Scientists have now determined that the stinger is able to continue pumping venom into its unfortunate victim even after the bee flies away, thanks to a unique double-piston pump-like mechanism, according to a new paper published in the Proceedings of the National Academy of Sciences.

Different species have evolved different mechanisms for delivering venom, which involves piercing the skin and then pumping venom from a gland or reservoir. Spiders, for instance, have muscles surrounding their venom glands, which contract and eject venom through hollow fangs. Bees, wasps, and ants deliver venom via their stingers, either by contracting muscles around the venom reservoir or through stiff elements called lancets working together to pump venom.

Honey bees (Apis mellifera) add a unique feature: Worker bees fly away after inserting their stingers in the target, leaving the stinger behind. The stinger continues to penetrate the tissue and pump venom on its own, a rare phenomenon known as autotomy. A honey bee's stinger has three main interlocking elements that form the venom canal: a stylet that widens to form the main pumping chamber and two sharp-tipped lancets that slide back and forth, piercing the tissue and pumping venom into the target. But the precise mechanism by which the pumping action is achieved has never been directly observed.

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Old-fashioned striped barbershop poles turn in place on a vertical axis, but humans typically perceive the stripes moving upward rather than turning with the pole. It's a well-known visual illusion arising from processing biases in human vision. According to a new paper published in the journal Nature, a similar effect could explain how butterflies often evade predatory birds: Their flight patterns and wing patterns combine to make it hard for predators to accurately gauge speed and direction.

"The stripes and spots on many butterflies’ wings interfere with the way visual systems try to guess the direction and speed of moving things, boosting false motion cues while hiding the butterfly's true heading," said co-author George Hancock of the University of Exeter in Cornwall. "The illusions interfere with the predator’s most basic visual targeting system and disrupt the final ‘ballistic attack’ in the tens of milliseconds when it commits to grabbing its prey, with no time to change course. As a result, birds and other predators will often simply miss."

Butterfly wings have long fascinated scientists, ever since the first documentation of the growth of said wings back in 1938. By 2021, researchers at MIT had captured on video the unique structural growth of butterfly wings—continuously, as a butterfly develops inside its chrysalis—for the very first time. Butterfly wings are an example of structural color in nature: the bright iridescent colors don’t come from pigment molecules but from what physicists call photonic crystals. The scales of chitin (a polysaccharide common to insects) are arranged like roof tiles. Essentially, they form a diffraction grating, except photonic crystals only produce certain colors, or wavelengths, of light, while a diffraction grating will produce the entire spectrum.

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