Life Histories: The Butterflies of Cascadia

A glorious sunny day in April after a long cool spring, it is Earth Day in Cowiche Canyon near Yakima, and the Cowiche Canyon Conservancy is hosting an educational field day. Scores of people armed with water bottles and binoculars are ambling down the trail toward presentations on birds, salmon, and geology as well as butterflies. Executive director Betsy Bloomfield fills me in on the conservancy’s endeavors as she guides me downstream to a station manned by David James.

James, a research entomologist at the Irrigated Tree Fruit Research Center in Prosser, has with coauthor David Nunnallee published Life Histories of Cascadia Butterflies (Oregon State University Press, 2011). It’s a unique and exhaustive documentary of the life cycles, from egg to caterpillar to chrysalis to adult, of all, save one, of the 158 butterfly species native to Cascadia, the region encompassing Washington, southern British Columbia, northern Oregon, and the Idaho panhandle.

When we reach James, he is addressing a small, mesmerized crowd about the canyon’s butterflies. Then, as if on cue, one of the book’s, and the day’s, star attractions flutters by: Lucia’s Blue, spring personified.

[+] Life history of Lucia’s Blue

Lucia’s Blue (Celastrina lucia)

A lovely little butterfly, generally quite rare, Lucia’s Blue is partial to Cowiche Canyon. In some years, James has in a few hours along the trail counted several hundred adults, which prevail in the canyon for four to six weeks starting in early April.

“You’d have to go a long ways to find another population of Lucia Blues,” says James.

The habitat is unusual for the Lucia’s Blue, as it’s usually found in the mountains.

The key, says James, is the red osier dogwood. “They’ve recently emerged. Once they’ve mated, the females will lay eggs on the red osier dogwood. They lay them on the flower buds and young leaves.”

The Lucia’s Blues develop very rapidly. Once the caterpillars are well-fed on red osier dogwood, they turn into a chrysalis, the stage in which they spend the rest of the summer and winter.

“It was supposed to be a retirement project,” wife and fellow entomologist Tanya James says of Life Histories. Although the time commitment on top of his “day job” in Prosser was tremendous, Tanya welcomed the enterprise. She loves to hike, she says as she doles out orange wedges to their daughters. But David needs a purpose. Just hiking to the top is not enough. Chasing butterflies is.

Lucia’s Blue was only recently described as a species, so recently that Robert Pyle’s definitive Butterflies of Cascadia, published in 2001, lists it as a subspecies. But of blues in general, writes Pyle, “few habitats in season are without their blues,” and the 20 blues species included in Life Histories represent two-thirds of North American species.

Pyle’s Butterflies of Cascadia and James and Nunnallee’s Life Histories work as unusually comprehensive companions in their coverage of the region. Life Histories is exhaustively unique. Although other books about butterfly life histories exist, none quite matches its thoroughness. As Pyle writes in his foreword to Life Histories, “In the whole world, no other comparable region enjoys a work of this scale, ambit, and acuity for its butterfly fauna.”

But what distinguishes Life Histories from general field guides and most butterfly books in general is that it treats the whole life of the butterfly. After all, the common image of the butterfly, the beautifully patterned adult, represents only a fraction of the insect’s overall life. Once they have courted and bred, butterflies lay eggs that hatch into larvae, or caterpillars. The caterpillars feed, grow, and molt a number of times before becoming chrysalides, or pupae. The adult butterfly forms within the chrysalis and emerges. The portion spent in each stage varies by species.

As James points out in his introduction, the adult of many butterfly species may live for only a week or so, “with 98 percent of their life history hidden or unknown in immature stages, so a full understanding of the factors controlling populations must necessarily include the study of immature stages.”

But information on the entire life history of many butterflies of many geographical ranges is sorely lacking. Fortunately, Cascadia is now not among those deficient ranges.

[+] Life history of the Mourning Cloak

Mourning Cloak (Nymphalis antiopa)

From his pack, James pulls a container of butterflies, captured earlier across the ridge in Bear Canyon. In contrast to the rarity of Lucia’s Blue, the butterfly he holds in the sun as it warms up is known throughout the world. While the Lucia’s Blue apparently is particular to the red osier dogwood as a host plant, the Mourning Cloak claims an enormous range at least partly due to its much more diverse diet.

Common to riparian corridors, lower elevation canyons, forest margins, and meadows from Alaska to Venezuela, from Lapland to Siberia, as Pyle notes, the Mourning Cloak populates all of Cascadia except the wettest coastal rainforest. Although it is a tough butterfly, like many butterflies it has trouble with cool and damp.

In fact, such is that aversion that one thing that Washington is not rich in is butterflies. Pyle calls it the “rot factor.” Much of Washington is simply too wet and cool for butterflies to thrive.

But where the Mourning Cloak lives, it thrives. Compared to its more ephemeral fellows, it is a long-lived butterfly. This one emerged last July, James tells his audience. It will lay its eggs shortly, and will still be around this coming July. The larvae, however, will pupate to escape the summer heat.

Now, warming in the sun, the butterfly rests on James’s hand. Butterflies, which are cold-blooded, need air temperatures of 65–70 degrees to fly.

Universal as it is, the Mourning Cloak can never lose its appeal, for it is stunningly lovely. Vladimir Nabokov, known for his Lepidoptera obsession as well as his novels, composed a poem about it in 1921:

Velvety-black, with a warm tint of ripe plum,

Here it opened wide; through this live velvet

Delightfully gleams a row of cornflower-azure grains,

Along a circular fringe, yellow as the rippling rye …

“Almost there,” says James as the Mourning Cloak stirs. “Sometimes they shiver.”

And off it goes.

[+] Life history of the Coronis Fritillary

Coronis fritillary (Argynnis coronis)

Rather than pupate to escape the heat as does the Mourning Cloak, the Coronis Fritillary goes to the mountains.

One of 16 species of fritillaries that occur in Cascadia, it returns to the valley in early September to feed on rabbitbrush and lay eggs on senesced violets.

A theme resonating this Sunday with many in Cowiche Canyon is “Project Butterfly.” The conservancy’s Bloomfield, for one, is nearly beside herself with the recent clinching of an agreement with the Yakima Schools and Heritage University that incorporates elements of Project Butterfly into their curriculums.

In 2005, with the help of the Washington Department of Fish and Wildlife, the Cowiche Canyon Conservancy was able to purchase 1,800 acres on Cowiche Mountain, a few miles upstream from here.

Snow Mountain Ranch serves as a vital preserve not only of the steadily retreating shrub-steppe landscape, but also of butterflies.

Projects include a small botanical garden with specimens of host and nectar plants and a children’s butterfly natural area. James is identifying habitat niches for possible reintroduction of butterfly species no longer endemic to the area. But most important is simply preservation and enhancement of habitat.

“If you provide the right habitat,” James has said, “they will come.”

[+] Life history of the Becker’s White

Becker’s White (Pontia beckerii)

Of the thousands of known species, the only butterfly that causes economic damage is the Cabbage White (Pierus rapae). Gardeners here today might indeed scorn the white butterflies that flit through the warm canyon. A closer look, however, would change their mood. The difference, besides diet, is the underside of their wings.

“The whites you see here are Becker’s Whites,” James tells a new group. Whereas the Cabbage White’s underwing is yellow, the Becker’s White’s is a beautiful green.

Even with the James family’s purposeful hikes, the bulk of the information for Life Histories was accomplished in a more controlled setting.

James tells me separately the same as his wife, that this was originally a long-considered project that would be finished sometime after “retirement.” His major work is directed toward biological control in vineyards.

But then he caught wind that David Nunnallee in western Washington was also documenting butterfly life histories.

“Once we got together, there was a synergy,” says James. “It became more of an achievable thing to get done in a shorter period of time.”

Although adult butterflies were collected in their habitat, and the finished book now provides an identification guide for whatever stage one might stumble across, one does not simply go out and track down eggs, caterpillar, chrysalis, and adult for each of 158 species of butterflies. For most of those species, that work required raising them in the lab.

On the one hand, such an endeavor was nothing new for James. He started raising butterflies as an aspiring eight-year-old lepidopterist in England.

But the reality of scientifically documenting each stage of these butterflies’ life histories was daunting.

“It was a phenomenal amount of work,” he says. Many of the species had never been reared before, and each species required a different way of getting them to lay eggs.

Their desire to produce such an exhaustive study required that James and Nunnallee raise each species multiple times.

“There was so much variation,” he says. Variation, that is, within an individual species. For example, the color of the larvae might vary depending on the host plants they feed on. Many of the entries in Life Histories include as many as six photographs of larvae in order to show that variation.

Each species, says James, represented a separate research project. But the final result is a wealth of biological and ecological knowledge that simply didn’t exist before their work.

The book has produced lots of “suggestions for further research,” says James with a smile.

[+] Life history of the Monarch

Monarch (Danaus plexippus)

One butterfly that does not make a showing in Cowiche Canyon today is the Monarch, probably the best-known butterfly in the world. It is actually much too early for Monarchs, and even later in the season it is not common. According to Life Histories, most Monarchs that occur in Cascadia probably originate in California. This and the longer migration of Monarchs between Canada and Mexico are threatened by decreasing habitat, particularly stands of showy and narrow-leafed milkweed, their host plants, due to agriculture and urban expansion.

Efforts to conserve appropriate habitat depend on a better knowledge of their migration routes. Although eastern Monarch migrations are fairly well understood, our understanding of western migration is sketchy. Although a recent study analyzed data on host plant availability and climate and predicted origins of migrating monarchs, it still does not clarify routes.

James is proposing to answer fundamental questions about western Monarch migration by enlisting prisoners at the Washington State Penitentiary in Walla Walla.

To conduct a rigorous study, which will take years, James will need tens of thousands of monarchs. Raising them himself is simply not feasible.

As part of the Sustainable Prisons project, which has been successful in western Washington in connecting prisoners with nature, officials at the penitentiary contacted James about possible prisoner participation in his work. According to James, prisoners have “reared endangered species more effectively than experts.’”

Starting this summer, prisoners at Walla Walla will begin raising the thousands of Monarchs necessary for James’s study. Once the butterflies have reproduced and metamorphosed, they will be tagged, transported to various sites near the California-Oregon border, and released.

In Wildness is the Preservation…

“We cannot protect what we do not understand,” write Nunnallee and James in their introduction. Their book has contributed enormously to our understanding of the full lives of butterflies and, it is hoped, will contribute to the protection of these wonderful animals.

The great British naturalist Sir David Attenborough has called Life Histories “magisterial,” a label that suggests much more than a collection of data and observations. A richly unique combination of traditional natural history and obsessive data-driven science, the book is, finally, beautiful—both in itself, for it is wonderfully photographed and written, and for showing us the enormously complex beauty of our Cascadian butterflies.