The arid American Southwest landscape doesn’t exactly scream “ideal habitat” to the human eye, but for some well-adapted animals and plants, this dry, barren desert is home sweet home. One such organism is an evergreen shrub that goes under the name greasewood, chaparral, and gobernadora, and creates its own unique blossom in the form of fluffy white creosote fruits. Amidst the fluffy white fruits lives another well-adapted organism, the Thistle-down velvet ant, which is actually a type of wasp. Comparing these tiny creatures to the shrub’s fluffy fruit capsules, it would seem logical that the wasps sprouted their fabulous white coats as a means of camouflage, but, as new research reveals, the story is not so simple.
"It's logical to assume Thistle-down velvet ants evolved their appearance to hide from predators among fallen creosote fruits," said Joseph Wilson, an associate professor in the Department of Biology at the Utah State University, in a statement. "But the wasps preceded the arrival of the creosote bush to the American Southwest by millions of years. So, we investigated other explanations for their white coloration."
Wilson and colleagues’ research, which was published in the journal Biology Letters, sought to ascertain if the emergence of fluff gave these animals thermoecological benefits, helping them to keep cool in such a hot environment. They combined genetic data with thermal imaging studies and used reflectance spectrometry to compare how capable the wasps and creosote fruit were in reflecting heat. Their findings indicated that the wasp’s white fluff did indeed help them survive in the hot desert and that this phenotype evolved as a means of thermoregulation rather than camouflage.
Wilson goes on to explain that one of the pitfalls of establishing the evolutionary pressure that drove a certain adaptation is assuming non-humans view traits in the same way humans do. “We learned not to judge a book by its cover," Wilson said. "Thistle-down velvet ants are white to us and look like creosote fruit, but we don't know exactly how they appear to the wasps' predators."
White coloration is rarely seen in animals living outside of arctic environments as in most environmental settings it’s a rather conspicuous color. Some animals use it as a form of aposematism, which is when organisms show off with bright and obvious coloration to warn animals that they’re dangerous. As this study concluded, thermoregulation is another explanation for the emergence of white coloration and if you’ve ever left the house on a very hot day in a black t-shirt, you probably have an idea as to why.
White clothes in hot weather = good
White beverages in hot weather =
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