Tiger beetles aren’t the first creatures you’d expect to find living among Yellowstone National Park’s boiling, acidic hot springs – but that’s exactly where scientists have found them, and they’ve just started to uncover how these hardy insects survive in such extreme conditions.
For years, researchers at Montana State University (MSU) have studied the tiny microbial lifeforms that thrive in Yellowstone’s thermal pools, but a new study – led by MSU entomologist Bob Peterson and colleagues from several universities – is one of the first to look at how insects manage to live in these scalding places.
The research focused on the wetsalts tiger beetle (Cicindelidia hemorrhagica), which lives at Mammoth Hot Springs, a geothermal area near the northern edge of Yellowstone.
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It all began back in 2006, when entomologist Leon Higley visited the park and was stunned to see the beetles crawling around the steamy, mineral-coated terraces. “I knew it was too hot for the beetles to be there,” Higley says, “and yet there they were.”
That spark of curiosity led to a long-term study. A decade later, researcher Kelly Willemssens began investigating how these beetles were coping with such high temperatures – especially when, in non-thermal habitats, the same species cools down by dipping its body in cold water, using evaporation to regulate temperature. But that trick doesn’t work in Yellowstone, where the water is not only hot (over 38 degrees centigrade or 100 degrees Fahrenheit) but also chemically harsh.
Insects aren’t warm-blooded, Peterson explains, and they can’t regulate their body heat like we can. "They basically become the temperature of their surroundings. So, when you get up to those levels, proteins start breaking down and you die.
"In a non-hot-spring environment, there's much more behavioural cooling versus anything we've seen in the park. So, what's the difference?”
So how do these Yellowstone beetles avoid overheating?
To find out, the team joined forces with Dr Chelsea Heveran, an expert in biomaterials at MSU’s engineering school. Heveran normally studies bones and biological structures to design better building materials – but in this study, she used high-powered electron microscopes to examine the beetles' bodies in microscopic detail.
"These tools will let you take a very small specimen and zoom in to thousands or even hundreds of thousands of times in magnification and see what it looks like,” Heveran says.
"It’s the same technology that would let you see the texture on a human hair, or let you see little, tiny holes in bone." This made it the perfect tool for spotting subtle differences in the beetles’ body structure.
What they found was fascinating: the Yellowstone beetles had evolved special features on their abdomens that helped reflect heat better than those of beetles living in cooler environments. These small physical tweaks could be the key to their survival.
Peterson believes these adaptations could inspire real-world innovations. "There’s the innovative potential to come up with products that might resist or reflect more heat,” he says.
"These organisms also no doubt have heat shock proteins that help them physiologically deal with heat. Understanding how those proteins or genes are turned on and off could have medical applications, and these discoveries will directly inform that.”
Find out more about the study: Hot springs, cool beetles: extraordinary adaptations of a predaceous insect in Yellowstone National Park, published in Annals of the Entomological Society of America.
Main image: Mammoth Hot Springs. Credit: Getty
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