Like Gollum in The Lord of the Rings, tiny Ptomaphagus parashant has evolved to cope with life in the darkness. The insect once had wings and eyes, but after spending millennia inside such tight quarters, its ancestors eventually began to lose the now frivolous appendages, according to a new study that will be published in the Coleopterists Bulletin (a coleopterist is a beetle scientist).
“Obviously, the eyes don’t fall off in a 24-hour period,” said study co-author Jut Wynne, an ecologist at Northern Arizona University.
“With these types of animals, they’re really shedding those features … over evolutionary time. This animal likely entered caves about 200,000 years ago.”
Most cave-dwelling animals subsist in an absolute or at least partially dark environment, which means eyesight is not much of an asset. And since the cave is only about 260 feet (80 meters) in length and just tall enough to crawl through, flight is not much of an advantage to a beetle, either.
So the bug traded in its outer-world traits for longer legs and extended antennae, which help it navigate in the gloom. (Also see “Pictures: 101 New Species of Beetles.”)
Wynne began exploring the limestone cave in Arizona’s Grand Canyon-Parashant National Monument in 2005. Compared with the Grand Canyon’s many caverns, this particular grotto is rather unremarkable, he added.
“It’s a crawly cave with a low ceiling,” Wynne said. “When I first set foot in that cave in ’05, I had no idea we were going to find several new species.” (Explore an interactive of the world’s largest cave.)
The scientist set bait traps of chicken livers and sweet potatoes to attract bugs, which he then collected and froze for later examination. One of them was the newfound fungus beetle—which, as its name suggests, likes fungi.The white spot where the eye once was contains an eye remnant. Photograph courtesy Jut Wynne
Though the fungus beetle isn’t Wynne’s only claim to fame—he’s also discovered the state’s first cave-adapted centipede as well as a new genus of cricket—he said it’s his cutest.
“I think they’re cute little beetles,” Wynne said. “They’re a nice chestnut-brown color, and they have an elongated antennae and cute, long legs. They have a very peaceful existence if you think about it.”
The next step is to figure out how these bugs interact with other animals within the cave, which is still replete with mysteries. The bait traps have captured hundreds of animals and may lead to further discoveries. (See more cave pictures.)
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