That Elusive Cabbage White Butterfly

If you've been looking for that cabbage white butterfly in the three-area county of Sacramento, Yolo and Solano to win UC Davis Professor Art Shapiro's "Beer for a Butterfly" contest, there's still hope.

Shapiro hasn't found it, either.

Butterflies aren't flying due to the elements: the  rain, the cold and the fog.

Shapiro, distinguished professor of evolution and ecology launched the "Beer for a Butterfly" contest back in 1972 as part of his scientific research. If you collect the first cabbage white butterfly (Pieris rapae) of the year, you can trade "the bug for suds."

Shapiro is offering a pitcher of beer (or its equivalent) for the first cabbage white butterfly  collected in 2018 in any one of the three counties.  “Since 1972, the first flight has varied from Jan. 1 to Feb. 22, averaging about Jan. 20,” he says.

The butterfly inhabits vacant lots, fields and gardens where its host plants, weedy mustards, grow. What does it look like? It's a white butterfly with black dots on the upperside (which may be faint or not visible in the early season). It 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.”

In its caterpillar stage, Pieris rapae is a pest. (See cabbageworm on the UC Statewide Integrated Pest Management Program website.)

Meanwhile, 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, who is in the field more than 200 days of the year, monitoring butterflies of central California (see his website), knows where to find the cabbage whites and usually wins the contest. He has been defeated only four times since 1972--and all by UC Davis graduate students.

The professor collects many of the winners in mustard patches near railroad tracks in West Sacramento, Yolo County.  Over the last eight years, five came from West Sacramento; two in Davis, Yolo County; and one in Suisun, Solano County.

The dates and locations:

  • 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 search continues!