No Rapae Today! Maybe Tomorrow?

No winner yet.

The annual “Beer for a Butterfly" or "Suds for a Bug" contest has not produced a winner.

But somewhere out there, is a cabbage white butterfly taking its first flight.

As you may remember,  Art Shapiro, distinguished professor of evolution and ecology at the University of California, Davis,sponsors the annual contest and the first person in the three-county area of Sacramento, Yolo and Solano who collects the first live cabbage white butterfly, Pieris rapae, of the new year--outdoors--wins a pitcher of beer or its equivalent.

The good professor was out looking again today. "It's another another gorgeous day," he reported to fellow scientists and others in an email this afternoon. "It FEELS like a 'rapae day,' but my schedule today is so convoluted (teaching, interviewing a job candidate, a meeting and two seminars) that I only had time to do a quick loop of community gardens...And I had just enough time to walk around Old East Davis for half an hour looking for Vanessas. I saw...nothing. But maybe somebody got a rapae today?".

Shapiro, who maintains a research website at, launched the contest in 1972 as part of his scientific research to record the first flight of the butterfly in the three-county area. It's a contest he usually wins. He has been defeated only four times, and all by UC Davis graduate students.

Since 1972, the first flight has varied from Jan. 1 to Feb. 22, averaging about Jan. 20.

In 2018, he collected the winner at 11:23 a.m. Friday, Jan. 19 in one of his frequented sites—a mustard patch by railroad tracks in West Sacramento, Yolo County.

The butterfly inhabits vacant lots, fields and gardens where its host plants, weedy mustards, grow.

The contest rules include:

  • It must be an adult (no caterpillars or pupae) and be captured outdoors.
  • It must be delivered 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 says.)
  • Shapiro is the sole judge.

The list of winners, dates and locations since 2010:

  • 2018: Jan. 19: Art Shapiro collected the winner in West Sacramento, Yolo County
  • 2017: Jan. 19: Art Shapiro collected the winner on the UC Davis campus
  • 2016: Jan. 16: Jacob Montgomery, UC Davis graduate student, collected the winner in west Davis
  • 2015: Jan. 26: Shapiro collected the winner in West Sacramento
  • 2014: Jan. 14: Shapiro collected the winner in West Sacramento
  • 2013: Jan. 21: Shapiro collected the winner in West Sacramento
  • 2012: Jan. 8:  Shapiro collected the winner in West Sacramento
  • 2011: Jan. 31: Shapiro collected the winner in Suisun, Solano County
  • 2010: Jan. 27: Shapiro collected the winner in West Sacramento

Shapiro has monitored butterfly population trends on a transect across central California for 46 years and records the information on his research website at  His 10 sites stretch from the Sacramento River Delta through the Sacramento Valley and Sierra Nevada mountains to the high desert of the Western Great Basin. Shapiro visits his sites every two weeks "to record what's out" from spring to fall. The largest and oldest database in North America, it was recently cited by British conservation biologist Chris Thomas in a worldwide study of insect biomass.

Shapiro, a member of the UC Davis faculty since 1971 and author of the book, Field Guide to Butterflies of the San Francisco Bay Area and Sacramento Valley Regions, has studied a total of 163 species of butterflies in his transect.