Surprises in the Field: Discovering a New Population of a Bog-Associated Butterfly
One of the greatest thrills of fieldwork is finding an unexpected or undescribed species at a field site. As a conservation biologist who studies invertebrates, I probably get more than my fair share of new encounters. The numbers are certainly in my favor: invertebrates make up over 90 percent of all known animal species on Earth, and we suspect that there are still tens (hundreds?) of thousands of undescribed species out there. Combine that with the fact that there just aren’t that many people looking for hidden microsnails or seep-associated caddisflies, and you have a real opportunity for discovery.
Every animal group has its poster child, though, and invertebrates are no exception. Of all the spineless creatures in the world, butterflies are among the most loved and celebrated. They are also relatively easy to find and observe, unlike a lot of our other more narrowly distributed or cryptic species. And they have quite a fan club. Because of this, butterfly species, particularly in depauperate areas such as the Pacific Northwest, are fairly well documented. Finding a new species or population of butterflies in a place like Oregon is rare—and cause for excitement.
I had a chance to experience this a couple summers ago while surveying a montane bog in Oregon’s Coast Range with a group of other biologists. Our mission: to find the valley silverspot butterfly (Speyeria zerene bremneri) and to document all other butterfly and bumble bee species at the site as part of a project done in collaboration with the Interagency Special Status and Sensitive Species Program and the Salem Bureau of Land Management.
While we did not find the silverspot (they are now thought to be extirpated from Oregon), I did notice an abundance of unfamiliar coppers flitting all around the open meadow. They did not look like anything I had encountered in that area before—small and delicate, with flashes of bright orange zigzags against cinnamon brown and dusky blue wings. The real surprise was the crisp scalloping and distinct smattering of spots and chevrons on the pale undersides of their wings. I netted a few, took notes and photos, and consulted my field guide, coming up with only one possibility—a mariposa copper (Lycaena mariposa). The thing was they had not been observed anywhere else in coastal Oregon before except for a single site much further south in the Siskiyou Mountains close to the California border. Most of the other populations were much farther east, in mountains of the Cascade Range.
Fast forward two years, and butterfly experts Bob Pyle and Paul Hammond are now analyzing specimens from this population as well as other populations from all across the mariposa copper’s range in the Intermountain West, revising the taxonomy of the entire species, and assigning several new subspecies designations. While the work is still in progress, it would seem that this particular population is most closely allied with the unusual Siskiyou population found further south along the Oregon coast. Other unique populations exist, like those associated with coastal bogs on Washington’s Olympic Peninsula. However, only two near-coastal populations are now known in Oregon.
Will this prove to be a new subspecies in Oregon? If so, what does that mean for its conservation status? Are there other populations out there, or is this a rare glacial relict? Does it use the same host plants as other mariposa coppers (small bog and forest cranberries)? What are its habitat needs and life cycle patterns? It can be a long road from discovery to answering some of these questions, but that’s part of the fun of scientific discoveries. Sometimes all it takes is a little curiosity to get things rolling.
by Candace Fallon, Senior Endangered Species Conservation Biologist, Public Lands Lead with contributions from Lepidopterist and Xerces Society founder, Bob Pyle