Moth Man and His Multitudinous Mysteries

Just miles from the site where the U.S. military detonated the first atomic bomb, scores of species entirely new to science are fluttering out of the dunes.

When Eric Metzler goes hunting, he packs the big guns: clothespins, tent stakes, a white sheet and a jolt of electricity. The setup doesn’t look like much by daylight. The sheet flaps like laundry in the desert wind. An extension cord swings haphazardly from a portable light.

But when darkness falls, the blue light casts an enchanted glow across the whole assemblage, and the animals Metzler seeks come circling close. “We know almost nothing about moths,” Metzler says as night closes in around his hand-built apparatus. “That’s why I’m here.”

“If you want to know what’s going on on Earth, you have to look at insects,” Metzler says.

Hearing this from an entomologist, one might chalk it off as a biased claim. But in this case, coming from a researcher who has discovered dozens of new species of moths over the last decade, the statement packs some weight. Metzler is a moth collector, and he is also an educator, an award-winning authority on regional biogeography, a former government executive at the state level, an inductee into the Ohio Natural Resources Hall of Fame and a collaborative researcher who brings together human communities across political and demographic lines.

Being well-versed in policy as well as entomology makes him “street smart,” says Pat Metzler, his wife and collection assistant of 50 years. Eric Metzler knows how to read insect populations as litmus tests for broader ecosystem health and shifts in climate. In short, when he speaks, we might all do well to listen.

A discovery like no other

Metzler has been a life-long lepidopterist—an enthusiast of moths and butterflies—and throughout his life he has leveraged this work to protect fragile places and promote citizen science. But in his third attempt at retirement, or his “third career,” as he calls it, he has stumbled across a discovery that may well become his greatest life’s work: the discovery of more than 50 new moth species in White Sands National Monument, New Mexico.

When Metzler first applied for a permit to study moths in White Sands, his goal was humble. In 2007 he chose a small study plot 2.5 kilometers (1.5 miles) long and 100 meters (about 325 feet) wide, with the intention of obtaining a general inventory of the moths within the national monument while gradually widening the transect out toward the boundaries of White Sands. The Western National Parks Association has helped to fund his work since 2008.

Within a year, Metzler had already discovered five moth species entirely new to science. At this point, the National Park Service stepped in and encouraged him to refocus his attention on finding new species.

For the last ten years, this has been Metzler’s project. He’s still working on that first small transect. “I’m never going to leave it,” he says. “Every year I find more species new to science. It’s just phenomenal. They just keep crawling out of the underbrush.”

An island of diversity

The stunning number of new species that Metzler has discovered may have to do with how little attention we devote to moths in general. Much more is known about the flashier but less diverse butterflies, which Metzler argues are simply “moths in fancy dress.”

But White Sands National Monument is also a rich and bewilderingly understudied site. The park has a striking military legacy: In 1945 the Alamogordo Bombing and Gunnery Range (now part of White Sands Missile Range) saw the first atomic bomb test. White Sands also has a long history of recreation. Since its designation as a national monument in 1933, it has seen countless tourists come to sled down the fine-grained white dunes that make it famous.

However, it wasn’t until 2005 that the park came onto the map as a biological hot spot. That year, a researcher at the University of California, Berkeley, published a groundbreaking study on lizards that had developed white skin to match the white dunes of the park.

White Sands National Monument is part of the largest gypsum dune system in the world, and the pale sand and a high water table make a perfect laboratory for diversity and evolution for more than just lizards. Metzler describes it as an “island” akin to the Galápagos, and this comparison is apt in many ways. Surrounded by desert rather than by sea, the living communities within the dunes have had time in isolation to adapt and thrive.

The mineral content of those drifting gypsum dunes and the moisture just beneath them have provided a platform for evolution to “build new species,” says David L. Wagner, a professor of ecology and evolutionary biology at the University of Connecticut and author of the Caterpillars of Eastern North America. Because of this, he says, White Sands is globally special: “You won’t find another place that’s only 20 square miles with over 40 species unique to it.”

More than skin deep

How does Metzler go about finding those unique species? He begins by setting black light traps that attract and funnel night-flying insects into a bucket. He usually knows immediately when he has found something new, but he brings the moths back to his home laboratory to sort them carefully. Unfamiliar moths are arranged on a spreading board, where their bodies are held in place by tiny pins. Under a powerful microscope, Metzler looks for clues that will tell him which family each moth might belong to: delicate hairs on the eyes, little tibial claws on the forefeet.

The real identification work requires dissection. Moth species can be identified by extraordinarily specialized genitalia—no two are alike from species to species. Metzler dissects the moths and removes the tiny genitalia, which are translucent and reddish when laid out on glass slides.

To read one of Metzler’s many journal articles about new species involves leafing through pages of photos of these almost sculptural organs, lined with folds and fibers, thin enough to allow the light from the microscope to illuminate them like lanterns. If Metzler finds genitalia that he’s never seen before, he sends off samples for mitochondrial DNA testing in order to confirm his discovery. In this way, Metzler has catalogued 650 species of moths in White Sands National Monument, 50 of which are entirely new to science, “all but five of which occur no place else on Earth,” he says.

No man is an island

Eric Metzler broke his arm recently (disappointingly, it was not from a moth attack). In his home laboratory, his wife, Pat, leans over the table, her silvery curls falling across her face as she contributes some ambidextrous help in bottling up moth legs to send off for DNA analysis. Metzler is quick to acknowledge how lucky he is to have had his wife’s support throughout his moth-hunting career.

He is quick, also, to acknowledge the support he’s had from other entomologists. “Nobody knows everything,” he says. “We can only move forward if we share.”

Several of his species are named in honor of fellow moth collectors. White Sands may be an island in a sea of desert, but Eric Metzler is not.

When asked about his importance in the world of entomology, Metzler is humble. His long-time colleague John Wilson, a former Audubon Society naturalist, says that not many people outside the world of moth specialists know about Metzler’s extraordinary work. He’s “sort of invisible.”

Wilson describes Metzler like the moths he hunts. In the biological world, an animal that can go undetected is called a cryptic species. Entomologists like Metzler, Wilson suggests, “are cryptic species.”

Yet for all his humility and lack of fanfare, Metzler has made waves, not just in taxonomy—describing more than 50 new species over a span of ten years is a remarkable scientific achievement—but also in the realms of conservation and outreach. At a time when national monuments are under fire from the federal government, Eric Metzler’s work has shown the value of protected spaces. Most of the species he has discovered are endemic—that is, found nowhere else in the world outside of White Sands. This makes the monument unique on this planet and—should it disappear—irreplaceable.

Metzler’s work in White Sands National Monument has also helped “create an important scientific bridge” between amateurs and professionals, says David Wagner. “Ten years ago, citizen science was only coming on board, but Eric had already built that bridge two or three decades ago.”

In addition to encouraging amateur collection and youth involvement in science, Metzler brought entomology—and White Sands—to the world stage in 2015, when he gave the Western National Parks Association the naming rights to one of his new moth species as a thank you for the support and funding he’s received from them over the years. WNPA put the naming of the species up for auction on eBay, garnering international news coverage. The winner named the moth after his mother.

All told, at a time when federal wildlands face an uncertain future, Metzler’s work has reinforced the global importance of national parks and monuments. “Cryptic species” though he may be, Metzler’s radius of influence is wide.

A taxonomy of loss

Every year, Metzler makes a pilgrimage to different museums and institutions to explore their behind-the-scenes collections of unidentified moths and confirm whether he has found species that occur elsewhere. It is not uncommon, he says, for institutions to place more effort on collecting animals and filing them away than on actually identifying them. Our planet is in the midst of what scientists are calling the Sixth Great Extinction, and many taxonomists are interested in collecting specimens while a species can still be found and waiting to document them at a later time.

This is Metzler’s undertaking, too. His home office is stacked high with cabinets full of pinned specimens from White Sands and elsewhere that will take a lifetime to identify. Many of these moths may be extinct within the span of that lifetime. It is a strange balance to seek as a scientist—to ride the thrill of discovery while also sitting with the knowledge that these new species might be slated for history books rather than field guides.

Of his astonishing new species discoveries, Metzler says, “This is going to be the documentation of what we lost.”

By Hannah Hindley