These bees actually change color when the air gets humid

Have you ever noticed how certain insects appear to shimmer differently depending on the light? It turns out that the weather may also be altering the appearance of one species of bee. Researchers have found that some iridescent bees, which resemble tiny living mood rings, may change color in response to humidity.In a way, the finding was made by accident. When museum bee specimens were put in humid chambers to soften them for scientific treatment, researchers observed that the specimens' colors occasionally altered considerably. "When you're not expecting it, it can be a bit alarming," Queen Mary University of London functional ecologist Madeleine Ostwald told Science News.There was a noticeable difference. The bees appeared richer and more blue-green in dry air with less than 10% humidity. However, they changed to a lighter, greener-copper tone at 95% humidity. Researchers also examined more than 1,000 photos of live sweat bees uploaded to the citizen science platform iNaturalist, matching the photos with the humidity levels at the time and location to see if this occurred in real life as well, rather than simply in preserved specimens.

The pattern persisted. What is going on, then? According to scientists, dampness causes the bees' exoskeleton's microscopic layers to gradually swell. These layers are in charge of structural color, which means that the bee's shimmer is caused by light reflecting off of microscopic physical structures rather than pigment.The wavelengths of light being reflected shift when humidity causes those layers to expand, changing the spacing. This causes the visual color to change toward greener, redder tones. To put it another way, humid weather can really alter a bee's ability to reflect light. Beyond bee aesthetics, this could have wider ramifications. Iridescent colors are used by many insects for communication, camouflage, and mating attraction. Environmental factors may have a greater impact on insect appearance than previously thought if humidity alters how those colors appear on a daily basis.