Every week, Richard Van Driesche travels to Jefferson to help his parents maintain their home. But when he cleans out the filter, instead of tossing the buildup, the Oregon State University entomologist brings a sample back to the lab.
“It’s always a roll of the dice when you check samples," he said. "You never know what you’re going to find."
On one rainy winter Saturday, while studying a sample under a microscope, Van Driesche found an object no larger than the head of a pin — something no one had seen in more than 30 years.
“It could’ve been anything," he said. "But I looked a little closer and I saw this little leg floating around. And then I found another little piece.”
Van Driesche showed his work to Kojun Kanda, an OSU biologist specializing in beetles, and together they realized that the little leg and the rest of the pieces belonged to a tiny diving beetle known as Stygoporus oregonensis, which had gone missing after it was first discovered in a bathtub in Oregon in the 1980s.
They agreed the rediscovery of S. oregonensis was monumental, and started documenting their work and eventually publishing a study last fall in the journal ZooKeys. But neither knew their finding would become the first step in a years-long project seeking to unravel the mystery of a vast, unknown, underground community that could stretch hundreds of miles on oceans beneath our feet.
Beetles in the bathtub
In spring 1984, a couple living in Dallas, Oregon, originally found the pale, blind diving beetle in their bathtub, which had been receiving water directly from the Willamette Lowland aquifer system. They sent a specimen to Dr. J. Cappizi, an entomology extension specialist at OSU. Cappizi soon realized the beetles were a new species and he suggested that the couple collect more. But soon after, the couple treated their well with chlorine, killing off what researchers thought would be the last of the beetle.
Ten years later, Jim LaBonte, who was an undergraduate at OSU during the beetle’s initial bathtub finding, published a paper about the discovery and named the beetle Stygoporus oregonensis.
LaBonte described them as subterranean predacious (predatory) diving beetles having a small size, depigmented body, no eyes and wings too small to fly.
David Maddison, biology professor and co-author of the study published last fall, said very little is known about the diving beetle's habits and lifestyle. It is believed their small size and lack of eyes are ideal for survival in aquifers but likely nowhere else.
“It’s amazing to think that insects can live in the aquifer underground,” he said. “But that’s why these things are so small. The little cracks and crevices down there are that small. You couldn’t fit in them if you were any bigger than they are.”
The tight, enclosed and rarely disturbed habitat is ideal for their survival, Maddison said, but it is also the reason so little is known about the beetles.
“Given that even a shallow well like the one in Jefferson is still 45 feet down, it’s not a habitat that biologists can sample very easily,” he added. “So we have to check the filters. But most people wouldn’t check their filters for something so small or even know what they were looking at if they saw them.”
“There’s all of this diversity down there beneath our feet that we still don’t know anything about,” Kanda said. “The more we look at the world we live in, the more we find that life has penetrated areas we didn’t even know existed.”
Oceans under our feet
While similar diving beetles have been found in other parts of the world, including Texas, Australia, Mexico, Europe, west Africa, Japan and New Zealand, S. oregonensis is the only known subterranean predacious diving beetle species in Oregon.
While Kanda and the rest of the research team knew that S. oregonensis was unique to the Pacific Northwest, when they completed DNA testing on additional samples found in Jefferson and Salem, they found something even more curious — the beetle’s closest known relative is found more than 1,700 miles away, in the Edwards-Trinity aquifer system in central Texas.
“It’s weird that this group of beetles is only known to come from Texas and Oregon,” Kanda said. “The idea that there are two beetle species from Texas and here that are so closely related to each other raises the possibility that there is a lot more we don’t know about in between.”
Even though they have tiny wings, the beetles are incapable of flight, so they must crawl around and swim instead. And they are blind so they use tiny hairs for navigation. While those characteristics are not ideal above ground — they dry out quickly on the surface — they are perfectly suited for survival in aquifers.
“They’re so well adapted to that environment,” Kanda said. “They’re not really designed for walking. Even if they could crawl out and find water, a blind, flightless beetle isn’t going to be a match for visual predators above the surface. So it’s very unlikely that they could survive for long outside of an aquifer.”
But the Willamette Lowland aquifer in Oregon and the Edwards-Trinity aquifer system are hundreds of miles apart.
“Given how far away Oregon is from Texas, it struck us as weird that they’re the closest relatives to each other,” Kanda said. “The more logical explanation in our minds is that there are more intermediates in between that we just haven’t discovered yet.”
But that’s not the only thing causing researchers to question the beetle’s origins and travel habits, Kanda said.
“The aquifers of Oregon are not that old,” he said, noting that the Willamette Lowland aquifer likely dates back to the Pleistocene Epoch (approximately 1.8 million to 11,700 years ago). “The Texas aquifers are really old (about 70 million years) and have been studied a lot. Also, there have been a lot of recently formed aquifers throughout California and no (diving beetles) have been found there.”
Maddison said the conditions are likely the result of one of two possibilities: The aquifer system used to be much larger and the beetles are millions of years old; or there are millions of similar diving beetles between Oregon and Texas that have yet to be discovered.
“The first possibility suggests that there was a group that was much more widespread than they are now, and what we’re finding is just the relics that are left,” Maddison said. “But the more interesting possibility is that there might be a lot more out there and we don’t know about them yet.”
Connecting the dots
Even though the OSU research team published a paper on S. oregonensis last fall, the team members aren’t finished attempting to unravel the mystery of where the tiny beetles came from before dropping into that Dallas couple’s bathtub.
In addition to regularly checking his parents’ filter in Jefferson, Van Driesche has taken to social media to ask other Willamette Valley residents to check their filters as well.
“Most of the people who have wells in the Willamette Valley are farmers,” he said. “So I put a post on social media on some farmers forums and I got tons of people responding. I haven’t found any again, but I’m still looking.”
This winter, Kanda completed his doctoral work at OSU and moved to Flagstaff, Arizona, to attend Northern Arizona University for his postdoctoral work. It's no coincidence, he said, that the university happens to be roughly halfway between Oregon and Texas.
“It would be really cool to see what else is living in the aquifer systems in between,” Kanda said. “It never ceases to amaze me that animal life has penetrated all of these niches all over the world. I think this really highlights how little we really understand about the biodiversity we share with this planet. Hopefully we’ll be able to step back and consider the hidden diversity right among us hopefully this will inspire people to check their own backyards. Because you never know what new species or new discoveries are there.”
Kanda said he’s only been in Flagstaff for a few weeks, but he’s hoping to visit several wells in the area to search for S. oregonensis once again.
“And not just places here, I’ve reached out to friends all over the U.S. who have wells to send me samples,” he said. “I haven’t been here very long so I haven’t found any … yet.”