A Posse for the Pieiris?

Jan 2, 2015

In case you've forgotten amid all the horn-blowing, champagne-sipping and singing of "Auld Lang Syne," the search is still on to collect the first cabbage white butterfly (Pieris rapae) of 2015 in the three county-area of Yolo, Sacramento and Solano.

So, pull on your boots, gather your posse, grab your nets and head off to where you think a cabbage white butterfly might be. That would include vacant lots, fields and gardens where its host plants, weedy mustards, grow.

Butterfly expert Arthur Shapiro, distinguished professor of evolution and ecology at the University of California, Davis, has sponsored the annual contest, "Beer for a Butterfly," since 1972. If you collect the first one, and it's verified by judge Shapiro, you'll win a pitcher of beer or its equivalent.

Professor Shapiro says it's too cold out for the cabbage white to fly. "Both yesterday (Thursday, Jan. 1) and today (Friday, Jan. 2) were too cold for even the 'hibernator' Vanessas to come out," he said. "I don't expect rapae before AT LEAST the 13th. By the way, the prognosis looks quite dry through mid-January, but the 90-day outlook is quite wet. In late September, I forecast 130 percent of average rainfall for the season. I'm sticking with that."

Shapiro not only knows butterflies but he knows the weather. His opinion of what's happening with the California weather? (Heavy rains, flooding, heavy rains, flooding.)

"It's a drought. We'd need at least 150 percent, better 200 percent of average seasonal rainfall to get the reservoirs to the point where water managers could undeclared the drought," he said in an email today. "But even if we got that--say with a series of Pineapple Express storms--prudence would dictate releasing some of the inflow to make room for more. It's a crap shoot. This is California, where booms and busts are born. By the way, the snow level has been high so far, so even though the snow is Sierra cement and has a high water content, the pack is mostly above 7500', so the area is pretty small (look at a satellite photo) and no part of the Sierra is carrying more than 50 percent of its seasonal storage capacity."

The "Beer for a Buttterfly" contest is all part of Shapiro's four-decade study of climate and butterfly seasonality. “It is typically one of the first butterflies to emerge in late winter. Since 1972, the first flight has varied from Jan. 1 to Feb. 22, averaging about Jan. 20.”

Shapiro says his long-term studies of butterfly life cycles and climate "are especially important to help us understand biological responses to climate change. The cabbage white is now emerging a week or so earlier on average than it did 30 years ago here."

Shapiro, who is in the field more than 200 days a year,  usually wins his own contest. He knows where and when to look. In 2014, he netted the winning butterfly at 12:20 p.m. Tuesday, Jan. 14 in West Sacramento, Yolo County. It ranked as "the fifth or sixth earliest since 1972."

The contest rules include:

  • It must be an adult (no caterpillars or pupae) and be captured outdoors.
  • It must be brought in alive to the department office, 2320 Storer Hall, UC Davis, during work hours, 8 a.m. to 5 p.m., Monday through Friday, with the full data (exact time, date and location of the capture) and your name, address, phone number and/or e-mail. The receptionist will certify that it is alive and refrigerate it. (If you collect it on a weekend or holiday, keep it in a refrigerator; do not freeze. A few days in the fridge will not harm it.)
  • Shapiro is the sole judge.

Shapiro has been defeated only three times since 1972. And all were his graduate students. Adam Porter defeated him in 1983; and Sherri Graves and Rick VanBuskirk each won in the late 1990s.

Shapiro maintains a website on butterflies, where he records the population trends he monitors in Central California.  He and biologist/writer/photographer Tim Manolis co-authored A Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions, published in 2007 by the University of California Press.