Watching Washington Butterflies With Bob Pyle: Number Fourteen

When the rows of brick houses were laid out in Hoffman Heights, Colorado at the outset of the second half of the twentieth century, shade trees were allocated by the block. One of the first post-war subdivisions on the edge of Aurora on the edge of Denver, Hoffman welcomed returning servicemen and their expanding families to its muddy, bare acres. A few of the old cottonwoods from the farms and ditches of the high plains were saved in the park and a couple of lucky backyards, but for the most part, the landscape we moved into in 1952 was a treeless one. The new young saplings were nurtured with water, care, and hope.

As it turned out, I was extremely fortunate in my neighborhood’s trees. My own 700- block of Revere Street had mostly Chinese elms and crabapples, good for shade and ammunition, but unhelpful for butterflies. But the very next block over and one up, the 800-block of Salem Street, got alternating green ash (Fraxinus viridis) and common hackberry (Celtis occidentalis). The former is a more-than-acceptable hostplant for the Two-tailed Tiger Swallow- tail (Papilio multicaudatus) and the latter, for the Hackberry Emperor (Asterocampa celtis). All I had to do was walk that block with a jam-jar and my eyes open in summertime, to harvest and take home for rearing any number of eggs, larvae, and pupae of these two species. I can still smell the breeding boxes and the pungent leaves wilting into a hot July afternoon, even now. The ready availability of these two beauties may have had a lot to do with butter- flies sticking to me.

And then it got better. I discovered that nearby Fairmount Cemetery, Denver’s most historic graveyard, was full of mature specimens of both trees. Their lower limbs were harder to reach than those of the young suburban stems. But in flight season, doubletails crowded the airways like 707s over Stapleton Field; and hackberries glided, flapped, and basked on tomb- stones and blue spruce limbs by the dozens. In the memorable summer of 1965, my mother    and I witnessed thousands of the honey-brown, eyespotted Asterocampa all over Fairmount, perching on every marker, mausoleum, and mud-puddle after summer showers. They’ve never been as abundant as that again, but to this day we go to Fairmount toward the end of the afternoon on the High Line Canal Butterfly Counts, to tally the reliable Hackberry Butterfly there. In those days I had no trouble netting many adults to mail live to Dr. Walfried J. Reinthal in Knoxville, Tennessee, a psychiatrist who did Asterocampa research in his spare time.

So when I first learned, many years later, that hackberry trees occurred in Washington, I began looking for their special butterflies right away. But was this a fool’s errand? Ray Stanford and Paul Opler’s 1993 Atlas of Western USA Butter- flies showed no Asterocampa records any nearer than east-central Utah. Could they possibly occur here?

Hackberry trees (genus Celtis) have co-evolved with two genera of butterflies for a long time. One of these, the snout butterflies (genus Libythea) actually exists alongside hackberry leaves in the Florissant Fossil Beds of Colorado- Oligocene lakebed shales-showing that this association goes back at least thirty-five million years. The other hackber- ry-feeding butterfly genus, Asterocampa, hasn’t been found as a fossil, but it too probably goes way back as an obligate Celtis chomper. Today, there are four species in North America: the Hackberry Emperor, the Tawny Emperor, the Dusky Emperor, and Empress Leilia (A. celtis, A. clyton, A. idyja, and A. leilia). BAMONA’s map shows A celtis occurring on both sides of the Rockies in Colorado, across southern Utah, barely into southeast Nevada, and abundantly toward the south and east. But to my knowledge, there has never been any hint of a Cascadian presence, or anywhere near-until now.

Since Celtis reticulata, the tough, sandpapery netleaf or western hackberry, was not included in C. Leo Hitchcock’s Botany 113 when I took Local Flora at the U. W. in 1967, it might as well not have existed for me. So the day I drove the long, steep slope from SR 14 down to Wishram, Washington, an old train-town on the Columbia River opposite Celilo, and spotted a scrubby tree beside the road that looked somehow familiar, and realized it was indeed a hackberry bush, I got mighty excited-and started looking for Hackberry Butterflies right away. Since then I have examined groves, stands, thickets, spinneys, and individual trees along the Columbia, John Day, Snake, and other basalt canyons, looking for the distinctive adults or immatures. Many insects feed on hackberry, from little pillbox-gallmakers to mourning cloaks. But in none of my searches did I see a hint of the warm brown flight, the fat, razorbacked green chrysalides or twin-horned larvae, nor even so much as a spent pupal cup in winter.

And then last fall, Ann Potter passed on a rumor from the Northwest Lepidopterists’ meeting in Corvallis, which I had missed: Ray Stanford thought he’d seen Hackberry Butterflies-in Washington! So I wrote to Ray and asked him, what’s up with that?

Ray is a very old friend and butterfly mentor who once lived across the street from my mother in Denver. For many years he conducted the Gilpin County, Colorado butterfly counts, which were routinely among the highest in the country. After he retired as a physician, Ray and Kit moved to Medford, Oregon, becoming Cascadians. Ray wrote back that he and Kit, in October of 2012, had taken a National Geographic cruise up the Columbia and Snake rivers, from Astoria, Oregon to Lewiston, Washington, nearly into Idaho. “The first stop,” wrote Ray, “was at the entrance to Hells Canyon Recreation Area, on the Idaho/ Washington border, in Asotin County about a mile north of the Oregon state line.” He went on: “While the captain checked us in, we disembarked to climb a hill to rest rooms and a nice garden with many birds, rabbits, and a few deer. Kit stayed there for a few minutes, to identify the birds, while I started back down the hill. At this time I was using Nordic walking poles to stay upright, but noticed that for hundreds of yards uphill, and a long way both up and down river, the dwarf forest consisted almost entirely of hackberry, Celtis reticulata, the netleaf hackberry. Then, to my great astonishment, an Asterocampa flew by, and back, landing on my shoulder! Then a second one flew by, and they went up in a typical spiral flight, and one returned to perch on my cap. Kit was not there yet, but another member of our group was nearby, so I asked him to photo the butterfly. He tried, but it flew away. Neither of the people near me knew a butterfly from a blimp, so I do not have a second qualified witness of this surprising confrontation. Kit and I also saw, separately, one flying specimen of Nathalis iole, a surprise also but not new from Asotin County, WA. That pretty yellow jewel of a butterfly is still unknown from Oregon !!”

So this was Ray’s amazing report. The Dainty Sulphur, by the way, was only the second record for Washington: my party had found seven males not far north of Ray’s location in 1975. But the Hackberry Butterfly was entirely new to Cascadia! Or not: After de- scribing the range of Celtis reticulata, Ray discussed what he called “the main feature: the known distribution of Asterocampa celtis in the Northwest.” He wrote, “I have today found time to put this unusual sighting of A. celtis into the context of recent records from others, indicating that the species could be moving north, as several others seem to be doing also. My sightings from Asotin Co, WA, are the only ones known to me from WA, OR, northern CA or northern NV. In Idaho there are old records from Gem and Washington counties (Lep Soc season summaries from long ago), and Twin Falls, Cas- sia and Oneida counties, from the 1970s and 1980s, mainly from George Stephens of Boise. Cliff Ferris determined at least one of his specimens as A. celtis montis, so there are documented records from south-central Idaho. Also Box Elder County, UT, and White Pine County, NV. So it is creeping up on Hells Canyon !!”

Those putative Idaho records had not made it into Stanford and Opler’s western atlas, nor into BAMONA’s data base, so I was previously unaware of them. But if sound, they do place Hackberry Butterflies much closer to Washington than we had imagined them to be. I was also surprised by the season. The Hackberry Butterflies of my youth in Denver were

exclusively single-brooded as far as I knew, flying once in midsummer. The only autumn flight I’d known was in Texas. So the existence of a potential second brood in the North is a lucky novelty, perhaps an adaptation to the lingering austral heat of the basalt canyons where the hackberry trees abound.

So now what? Do we pop Asterocampa celtis onto the state list? I don’t for a minute doubt the judgment of my old friend and teacher Ray, one of the most knowledgeable and experienced lepidopterists in the country, let alone the West. However, as he properly pointed out, in the absence of a voucher specimen or a photograph, there really should be a second “qualified witness” to a new record of this importance. This is how the Variegated Fritillary (Euptoieta claudia) made it into the state checklist last year-because two separate observers turned in reliable reports in the same season and region-and even that was a stretch of the nor- mal procedure for validating a new member of the state’s fauna. But Ray himself suggested where we should go from here:

“I now think forward,” he wrote, “which is always the best place to search for new information. First, we both know that the total range of a larval foodplant, say Celtis, is usually much larger than that of any particular butterfly species that uses it [as its host]. I did not expect to see an Asterocampa celtis along the Snake River in WA, although I learned …that it has been recorded, and collected, farther upriver on the Snake River in Idaho. Someone younger and more mobile than I am should return to the scene of the crime, as described above, with net and/or camera, probably in June or again in September. I predict that my sighting will be confirmed, and that this new butterfly to Asotin Co, WA, will eventually be found westward and northward, with Celtis reticulata… I shall point my rear-view mirror the other way, and hope to watch the fireworks that might await us.”

And so, an expedition has been planned for this fall to take up Ray’s challenge. Though we are not that much younger or more mobile, another long-time field companion and WBA member, David Branch, and I will be heading into the wilds of deepest Asotin in search of hackberries and the butterflies that love them. The second half of this column, after discussing the range of net-leaved hackberry trees in the West, will report our results-fireworks or not!

The author gives special thanks to Ray Stanford for the hot tip and for the use of text from his informative and entertaining e-mail! And to Jim Brock and Janet Chu for coming through quickly with their beautiful photographs.

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