A pipevine swallowtail nectaring on wild radish on Jan. 25, 2014 along Gates Canyon Road, one of Art Shapiro's transects. (Photo by Kathy Keatley Garvey)

Rising from the Ashes--Some Day

People ask me all the time where butterflies go when it rains. Now they're asking me where they go when it burns.

In a word, to the Elysian fields. They have nowhere else to go!

The unprecedented wildfires have destroyed very important butterfly habitats in 2020, particularly in the High North Coast Range where a million acres – mostly in the Mendocino National Forest – have burned. We have been doing biogeographical survey of the butterfly faunas of this region beginning in 1974.  Earlier fires largely removed the fir forest from the upper reaches of Snow Mountain (summit 7056'), leaving it covered in successional montane chaparral. But Goat Mountain (6112'), Hull Mountain (6831'), Anthony Peak (6958'), and Black Butte/Mendocino Pass (7455') still had many intact plant communities containing rare and relict species (many of which were isolated and far-removed from their core ranges in the Sierra Nevada and/or the Klamath Mountains). These included very rare wet meadows (as at Plaskett Meadows near Mendocino Pass) and treeless “balds” on rocky summits, usually facing southwest, producing a simulacrum of alpine fell-fields typically found several thousand feet higher.

We had documented roughly 115 species of butterflies in these places. Some, like the Nevada Arctic (Oeneis nevadensis) and the Arctic Skipper (Carterocephalus palaemon) were at their southernmost range limits, not just in the Coast Range, but globally. One butterfly new to science, the Bald Hills Satyr (Cercyonis incognita), was discovered at mid-elevation on Goat Mountain (100% of which burned) and in a few spots farther north.  All of its known habitats may have burned—we won't know until we can get in, not before next year—and it is possible that it is extinct. In addition, we discovered that the widespread, familiar Pine White (Neophasia menapia) was apparently two sibling species on Goat Mountain and near Seven Troughs Spring in the Mendo Pass area, flying several weeks apart and with morphological differences. We did publish that one! All the known localities for the late-season entity have burned, too. This situation is of special interest because the idea that species could originate through temporal isolation has been discussed for many decades, but rarely if ever firmly documented. (The classic case, in field crickets, has been falsified by DNA analysis.) We have to be thankful that we got the data we did before the holocaust. Now, of course, the pressure is on to digest it.

Recovery of the butterfly faunas cannot occur until the vegetation resources they depend on come back—and they may never do so. Glacial relics, like the unique four-petaled Plaskett-Snow Basin race of the bog shooting-star Dodecatheon jeffreyi –personally, I think it deserves species status—may never come back. Nor many of the stranded alpine and edaphic (soil-specialist) species, because they are so far from any conceivable seed source. We have to hope they have persisted in the soil seed bank and may in time recover. Only then can the butterflies re-establish—if there are sources of potential colonizers. The farther any unburned sources and the weaker the dispersal capabilities of the butterflies, the longer the lag times to recolonization. Only the most vagile and broadly-adapted species are likely to recolonize a burned area of a million acres anytime in the next half-century or more.

The fires of 2020  were fed by the combination of 60 percent of recent mean precipitation in the 2019-2020 rainfall year and extraordinary evapotranspiration demand on the vegetation resulting from the hottest late summer on record. Yes, climate change is real. And our Coast Range butterfly faunas may never be the same again.

Resources:

• Sympatric, temporally isolated populations of the pine white butterfly Neophasia menapia, are morphologically and genetically differentiated, PLOS ONE, published May 31, 2007. Authors: Katherine L. Bell, Christopher A. Hamm, Arthur M. Shapiro and Chris C. Nice, https://doi.org/10.1371/journal.pone.0176989
• A New Species of Cercyonis (Lepidoptera: Satyridae) from Northern California, Bulletin of the Allyn Museum, Florida Museum of Natural History, published Sept. 5, 2012. Authors: John F. Emmel, Thomas C. Emmel and Sterling O. Mattoon

Contact: Art Shapiro at amshapiro@ucdavis.edu

For the first butterfly, it was the right place at the right time.

An alfalfa or sulfur butterfly (Colias eurytheme) fluttered into our pollinator garden in Vacaville to sip some nectar from a Mexican sunflower (Tithonia rotundifolia). It lingered for several minutes.

But on another day, several miles away, an alfalfa butterfly wandered into a rural nursery, and splat! Nailed by a yellow sticky trap, which is used to lure, trap, monitor and detect insect pests. 

Second butterfly: wrong place at the wrong time.

Note, however, that in its larval stage, C. eurytheme  is a major pest of alfalfa. 

"There are four to seven generations per year of alfalfa caterpillar, and each generation is closely synchronized with the hay-cutting cycle so that the caterpillar pupates before cutting occurs," according to the UC Statewide Integrated Pest Management Program (UC IPM) website. "Caterpillar populations usually result from a flight of butterflies into the field when the alfalfa is less than 6 inches tall. Extremely large numbers of adults migrating between fields are often present from June to September in the Central Valley and from May to October in the southern desert."

UC IPM points out that factors contributing to economically significant caterpillar numbers are:

• Slow and uneven growth of the crop
• Lack of natural enemies
• Hyperparasites (other parasitoid wasps attacking the natural enemy wasps reducing their numbers)
• Hot, dry weather.

Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, says 2020 proved to be a major  outbreak year for the alfalfa butterfly in the Sacramento, Yolo and Solano counties. (See butterfly invasion in the Aug. 28, 2020 Bug Squad blog).

Ever seen one in a sticky trap? Often you'll see assorted--and tiny--flies, gnats, beetles, leafminers, psylids and the like. So a yellow butterfly in a yellow sticky trap really stands out.

Happy Labor Day!

And what an appropriate time to post an image of a Gulf Fritillary, Agraulis vanillae, depositing an egg!

The females lay their eggs on the tendrils and leaves of the butterfly's host plant, the passionflower vine (Passiflora) but we've seen them depositing eggs on nearby fences where the vines climb.

Butterfly guru Art Shapiro, distinguished professor of evolution and ecology, says the Gulf Frit was introduced into southern California in the 19th century, in the vicinity of San Diego in the 1870s. It was first recorded in the Bay Area before 1908. "It became a persistent breeding resident in the East and South Bay in the 1950s and has been there since." Once prevalent in the Sacramento area in the 1960s, it "seems to have died out by the early 1970s," he said.  Then in 2009, it began making a comeback in the Sacramento area."

It is a dazzling butterfly, what with its brilliant orange wings and spectacular silver-spangled underwings.

The Gulf Frit, also called the "passion butterfly," is usually quite skittish--except this one wasn't. We captured this image on Labor Day weekend in Vacaville, Calif., with a short macro lens--60mm--mounted on a Nikon D500.

She didn't seem to mind.