Clint Pogue spent 2020 grieving. There was, that pandemic summer, much to lament — the viral deaths, the shuttered businesses, the shredded social fabric. In addition to the headlined horrors, though, Pogue mourned another, more obscure tragedy, one that he faced with minimal public attention and support: the collapse of the Behren’s silverspot butterfly.
The Behren’s silverspot is the color and size of an apricot. It’s a fritillary, one of a group of butterflies whose name derives from the Latin word for “dice box,” perhaps owing to the intricate dots that mark their wings. The Behren’s once sailed through the fog-shrouded prairies that fringe California’s northern coast, sipping the nectar of goldenrod and asters. Over decades, however, development consumed its meadows, and invasive plants squeezed out the early blue violet, the caterpillars’ sole food source. Today, just one population endures, in Mendocino County. And Pogue, a biologist with the U.S. Fish and Wildlife Service, is the person primarily responsible for saving it.
Every year, Pogue and his colleagues survey the Behren’s silverspot, much the way scientists survey butterflies everywhere: They walk. Back and forth, through reedgrass and thistle, the Pacific glinting beyond, scanning for the silvery flash of their underwings. Pogue launched his 2020 surveys in early July, as the world hunkered down indoors and the silverspot’s spiny caterpillars metamorphosed into winged adults. He didn’t see any butterflies that month, or in August or September. One biologist did glimpse a silverspot that summer, but the sighting occurred outside of a formal survey, so it didn’t technically count. The official tally was zero. Such surveys are imperfect, yet it seemed conceivable that just a single Behren’s silverspot remained on Earth — an endling, the final, lonely member of a species on the brink.
The silverspot’s disappearance was hard on Pogue. Although a coalition of agencies and nonprofits worked on its conservation, he was the species’ recovery lead. His job description was to ensure the butterfly’s survival, and he feared he might fail. “Looking week after week for butterflies, and not seeing them and not seeing them, it’s disheartening and scary,” he told me. Yet if the collapse wounded him, it also galvanized him to adopt a new approach, one that may yet save his beloved, obscure species.
OVER THE LAST CENTURY, researchers have calculated, human activity has accelerated the natural rate of vertebrate species extinctions up to a hundredfold. And while insect data is notoriously sketchy, the spineless masses may be in even rougher shape: According to one controversial analysis, insects are going extinct eight times faster than birds, reptiles and mammals. The West’s butterflies epitomize this trend. In one study, ecologist Matt Forister and his colleagues sifted through more than 40 years of butterfly counts across the West and found that surveyors glimpsed 1.6% fewer every year. And such incremental declines can compound quickly. Forister suggested visualizing a mountain meadow spangled with butterflies, then returning two decades later to find nearly 30% of them gone. “That’s a massive reduction in the number of individual pollinators flying around,” he told me.
Even so, most of our conservation efforts are directed toward saving the furry and the warm-blooded. Wolves, bears and other megafauna attract substantial constituencies and funding for research; not so the Nevada cloudywing or the Uncompahgre fritillary. Anti-insect discrimination is so strong that entomologists have a term for it: “institutional vertebratism.”
“That’s a massive reduction in the number of individual pollinators flying around.”
Institutional vertebratism pervades America’s state and federal agencies. According to Scott Black, executive director of the nonprofit Xerces Society for Invertebrate Conservation, many Western states don’t grant their wildlife departments clear authority to protect insects. Although insects account for an estimated 75% of earth’s animal diversity, vertebrates outnumber them on the U.S. Fish and Wildlife Service’s threatened and endangered species list by more than four to one. Among the 50 Western butterflies that Forister deems most imperiled, just 15 receive federal protection.
Even those insects that have landed on the list struggle to garner adequate support. In 2018, for instance, the federal government spent just $45,000 on Behren’s silverspot recovery. “I feel like that’s what I’m doing all the time — chasing down pots of money here, pots of money there,” Pogue said. Other butterflies, like the Myrtle’s silverspot and the Uncompahgre fritillary, received still less support.
But while more funding would surely help, it isn’t likely to arrive without a broader shift in how we perceive insects. Consider the Behren’s sister subspecies, the threatened Oregon silverspot, which the U.S. Fish and Wildlife Service has been working to conserve for longer. In 2018, it received around 10 times as much funding as the Behren’s. Today, the agency and its many partners pull and burn weeds, rear silverspots in captivity and even train dogs to sniff out their caterpillars. Although their efforts have so far kept the subspecies from oblivion, most of its five remaining populations continue to decline for reasons that remain murky even to scientists. Perhaps it shouldn’t surprise us that a half-million-dollar annual recovery budget — the median cost of a home in Portland — is inadequate to reverse the century-long decline of the Northwest’s coastal prairies.
“If I had $5 million placed in my lap tomorrow, the things that we could accomplish as a team would just be incredible,” Samantha Derrenbacher, the Oregon silverspot’s recovery lead, told me. “But my hands are tied with how much we can do on a yearly basis.” We have yet to treat butterflies and their brethren as “charismatic microfauna,” as Derrenbacher put it, as glorious in their way as condors and cougars.
EVERY SPRING, Behren’s silverspot caterpillars form a tough sepia pupa, drawing leaves around themselves with silk. The metamorphosis that occurs within this chrysalis is weird and grisly: Behren’s caterpillars, like the larvae of all butterflies and moths, essentially digest themselves, melting down into a protoplasmic sludge that retains only a few precious groups of cells, known as “imaginal discs.” These cellular seeds will, weeks later, sprout into the legs, wings, antenna and other structures of an adult butterfly. Incredibly, imaginal discs retain memory: Scientists who exposed caterpillars to a certain scent and then shocked them found that adult moths later avoided that same scent.
This concept — a thorough transformation that nevertheless recalls your past — resonates with Clint Pogue, perhaps because he grew up in an insular corner of southeastern Missouri that few ever leave, only to end up in California; or perhaps because he was a botanist whose love for plants led him to lepidoptery. “I’ve changed a lot in my life,” Pogue told me. “Sometimes, to fully change, you have to break down completely to your core values or tenets — and those are your imaginal discs.”
“Sometimes, to fully change, you have to break down completely to your core values or tenets — and those are your imaginal discs.”
Likewise, the crusade to save the Behren’s silverspot may be rising from the goo of institutional vertebratism. Soon after Pogue’s tragic 2020 surveys, he began to contemplate drastic measures. Fish and Wildlife and its collaborators had spent years attempting to restore the butterfly’s habitat on a shoestring — fighting weeds, planting violets, even deploying livestock in lieu of grazing elk — yet it still crashed. Meanwhile, the Oregon silverspot, though hardly thriving itself, had benefited from captive rearing programs, in which entomologists hatched eggs and raised caterpillars in the sheltered confines of zoos. Perhaps a similar program could boost the Behren’s numbers and preserve it from extinction. Pogue simply needed to find a few butterflies, if any existed.
In 2021, Pogue and his colleagues focused on a new meadow, and this time spotted almost 50 Behren’s silverspots. The entire population could still land on your forearm, yet it meant that the butterfly wasn’t immediately doomed after all. Pogue captured seven females who’d already mated and brought them to the Sequoia Park Zoo in Eureka, California, to lay their eggs. The zoo’s butterfly program director, Christine Damiani, found herself entrusted with being midwife to an organism that had never before been raised in captivity.
As in nature, Damiani discovered that each phase of the Behren’s yearlong lifecycle brought a new hazard. The pinhead-sized eggs grew mold, and every violet leaf the caterpillars devoured — 16,000 all told — first had to be hand-picked, inspected and triple-washed to ensure its quality. As 2021 rolled into 2022, attrition eroded the insect’s ranks. Pogue’s seven females laid around 3,000 eggs, which hatched into 1,500 caterpillars. Only 250 survived the winter, which then formed 110 pupae full of ooze and imaginal discs. The overwhelming sense of responsibility that gnawed at Pogue found a new host.
“Every life stage, I worry about them,” said Damiani, who took to calling herself the Mother of Caterpillars. “Are they too wet? Are they too dry? Am I not going to have enough food for them all? Oh my God — what if I can’t do this?”
In summer of 2022, Damiani and some volunteers drove the surviving pupae to the same coastal prairie where Pogue had collected their mothers. They hung them in outdoor enclosures, checked them each day, and released any butterflies that emerged overnight. In the end, 80 new silverspots drifted forth to breed — a little more charismatic microfauna in a world sorely lacking it. “What more rewarding job could you have than trying to reverse the extinction of a species?” the Mother of Caterpillars said.
For Pogue, the releases felt more like a first step than a conclusion. The butterfly’s survival, like that of so many others, remained precarious, and the cadre of people devoted to it was still tiny and beleaguered. What’s more, their success had ironically made their burden even heavier: In the second year of the breeding program, Damiani had coaxed four times as many caterpillars into existence, which meant four times as much tedious leaf-picking and washing. Yet the grief Pogue felt in 2020 had hardened, chrysalis-like, into resolve. Recovering the Behren’s was “decades or more away,” he wrote on his Instagram page, @imaginal_discs, “but today is a milestone and an achievement.” Thousands of species stumble closer to extinction’s cliff daily; the Behren’s silverspot had flitted a few wingbeats away from the edge.
Ben Goldfarb is a High Country News correspondent and the author of Eager: The Surprising, Secret Life of Beavers and Why They Matter. His next book, on the science of road ecology, will be published by W.W. Norton in 2023.
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This article appeared in the print edition of the magazine with the headline Watching a species disappear.
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