Yes, it's true.

You can exchange suds for a bug.

That would be a cabbage white butterfly for a pitcher of beer or its equivalent.

And it's all in the interest of science.

Art Shapiro, distinguished professor of evolution and ecology at the University of California, Davis, is sponsoring his annual “Beer for a Butterfly Contest,” starting Jan. 1.

The first person in the three-county area of Sacramento, Yolo and Solano who collects the first cabbage white butterfly, Pieris rapae, of the new year--outdoors--and drops it off live  in the Department of Evolution and Ecology office--wins a pitcher of beer or its equivalent.

Shapiro, who maintains a research website at http://butterfly.ucdavis.edu, 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.

“I spotted the male butterfly dorsal basking (sunbathing) on low vegetation shortly after the first cumulous formed at 11 a.m.,” the professor remembers. “As I approached to collect it, a small cumulus occluded the sun and it closed its wings over its back--allowing me to just pick it up without using my net at all, and drop it into a glassine envelope. It turned out that that was the ONLY cloud that crossed the sun in the next two and a half hours! It got up to about 60 degrees and was a gorgeous day with a trace of a west wind.”

He described the butterfly as quite yellow instead of white. “Cold weather promotes sepiapterin formation, so early ones are often quite yellow.” 

This is the eighth year since 2010 that the winning butterfly has been collected in Yolo County. In 2017, Shapiro found the winner on the UC Davis campus; in 2016, graduate student Jacob Montgomery netted the winner outside his home in west Davis, and Shapiro collected all five winners from 2012 to 2015 in West Sacramento.  He found the 2011 winner in Suisun, Solano County.

Shapiro's graduate student, Adam Porter, defeated him in 1983.  Two other graduate students, Sherri Graves and Rick VanBuskirk, each won in the late 1990s.

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.”

In its caterpillar stage, Pieris rapae is a pest of cole crops and is known as "imported cabbageworm." The larvae  "chew large, irregular holes in leaves, bore into heads, and drop greenish brown fecal pellets that may contaminate the marketed product, according to the UC Statewide Integrated Pest Management Program's website.) "Seedlings may be damaged, but most losses are due to damage to marketed parts of the plant."

Ready to join the hunt for the first-of-the-year cabbage white butterfly? And try to defeat the good professor?

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, Yolo County
• 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 http://butterfly.ucdavis.edu/.  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.