Suds for a Bug? Get Out Your Net!

Suds for a bug? Get out your net!

If you collect the first cabbage white butterfly of the year in the three-county area of Sacramento, Solano and Yolo, you'll win a pitcher of beer or its equivalent, compliments of Art Shapiro, UC Davis distinguished professor of evolution and ecology.

Shapiro is sponsoring his 48th annual Beer-for-a-Butterfly Contest and it's all in the name of research--to determine the first flight of the cabbage white butterfly, Pieris rapae. Since 1972, when he launched the contest, the first flight has varied from Jan. 1 to Feb. 22, averaging about Jan. 20.

The butterfly inhabits vacant lots, fields and gardens where its host plants, weedy mustards, grow. The male is white. The female is often slightly buffy; the "underside of the hindwing and apex of the forewing may be distinctly yellow and normally have a gray cast,” Shapiro said. “The black dots and apical spot on the upperside tend to be faint or even to disappear really early in the season.”

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.

Shapiro, who maintains a research website at http://butterfly.ucdavis.edu, usually wins his own contest and did so again in 2019. He collected the winner near the Suisun Yacht Club, Suisun City, Solano County, at 1:12 p.m., Friday, Jan. 25. 

Shapiro has been defeated only four times, and all by UC Davis graduate students: Jacob Montgomery in 2016; Adam Porter in 1983; and Sherri Graves and Rick VanBuskirk each defeated him in the late 1990s.

The list of winners, dates and locations since 2010:

  • 2019: Jan. 25: Art Shapiro collected the winner near the Suisun Yacht Club,Solano County
  • 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

The 2019 winner was the earliest recorded in Suisun City in 47 seasons, said Shapiro. That day he noticed dandelions, mustard, radish and mallow in bloom and a few Picris (sunflower family) in the area. "But near the Suisun Yacht Club (703 Civic Center Blvd., Suisun City) at 1:12 p.m. I saw a rapae. It didn't land and I had to take it in the air. It's a small and very heavily infuscated male.” It had just eclosed that day, he said.

The UC Davis professor has monitored butterfly population trends on a transect across central California since 1972 and records the information on his research website. 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. He visits his sites every two weeks "to record what's out" from spring to fall, weather permitting. He has studied more than 160 species of butterflies in his transect. 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 and illustrator Timothy D. 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. Shapiro is a Fellow of the American Association for the Advancement of Science, the Royal Entomological Society, and the California Academy of Sciences.

Meanwhile, if you want to learn more about this butterfly, see the data on the UC Integrated Pest Management Program website. In its larval stage (cabbageworm), it's a pest.

And if you want a free pitcher of beer (or its equivalent), don't leave home without your net!