Art Shapiro Does It Again
He Wins the 2025 Beer-for-a-Butterfly Contest
UC Davis distinguished professor emeritus Art Shapiro has done it again.
He won the 2025 Beer-for-a-Butterfly Contest, a scientific research project he’s sponsored since 1972 to seek the first cabbage white butterfly of the year in the three-county area of Sacramento, Yolo and Solano.
The person who collects the first live butterfly, Pieris rapae, and is judged the winner, receives a pitcher of beer or its equivalent.
Shapiro will be drinking his own beer.
He collected the butterfly by hand along railroad tracks in West Sacramento, Yolo County, at 12:13 p.m., Thursday, Jan. 23. He took it back to his campus office in Storer Hall in a Big Blue soda bottle.
“When I collected it, I looked in my pocket for the little pill box to put it in,” he said. “It was not there.”
What to do?
Big Blue Soda Bottle
Nearby, he spotted a trashed Big Blue soda bottle at an unoccupied homeless encampment. He gingerly lowered the butterfly inside the bottle and wadded a paper towel to close the opening.
“I don’t know what Big Blue is,” he said Friday. “Never heard of it.” (It’s a soft drink bottled in Waco, Texas and is a popular Southern soft drink along with its older cousin, Big Red. Big Blue is reportedly three times sweeter than Big Red.)
In an email with the subject line, “Pop Goes the Weasel,” to his posse of fellow scientists and butterfly enthusiasts, Shapiro wrote “The minute I arrived at my West Sac site---at noon--I KNEW rapae would be out. It was, A female showed up at 12:13 and I caught her visiting Raphanus three minutes later! She’s in the fridge in my lab at Storer.”
He’d been looking for it since Wednesday, Jan. 1. On Jan. 15, he wrote: “West Sac has generated more first rapae than any other location, probably because much of the route is along the south-facing side of the railroad embankment. The forecast looked perfect, so I went there. 64F, clear, dead calm. The lack of rain this month has dried up all the mud and most of the puddles. The vegetation has if anything regressed; there is less in bloom now than last time--one Hirschfeldi (mustard family), three Raphanus (wild radish), and several each Melilotus alba (white sweetclover) and Sonchus (sow thistles). Five homeless, including a young woman with a dog that looks like a dingo and has its ribs showing. One butterfly--an antiopa (mourning cloak). No rapae. It sure felt like a rapae day, though!”
His collaborator and former doctoral student Matthew Forister, the McMinn Professor of Biology at the University of Nevada, Reno, provides an annual graph. “Only a few days behind model prediction, as you can see by the position of the red dot (this year) a bit above the line,” noted Forester, who received his PhD in ecology from UC Davis in 2004.
Earliest Possible Flight Date
Shapiro, who has monitored butterfly populations in Central California since 1972, and maintains a research website at http://butterfly.ucdavis.edu/, says the point of the contest "is to get the earliest possible flight date for statistical purposes.” It's all part of his scientific research involving long-term studies of butterfly life cycles and climate change.
P. rapae is emerging earlier and earlier as the regional climate has warmed, Shapiro says. "Since 1972, the first flight of the cabbage white butterfly has varied from Jan. 1 to Feb. 22, averaging about Jan. 20."
Since 1972, Shapiro has been defeated only four times and those were by UC Davis graduate students. Adam Porter won in 1983; Sherri Graves and Rick VanBuskirk each won in the late 1990s; and Jacob Montgomery in 2016. The first three were his own graduate students.
Same West Sacramento Site
Shapiro collected or recorded the last four winning butterflies at the same railroad site in West Sacramento. The dates and times:
- The 2024 winner: 11:30 a.m., Monday, Jan. 29.
- The 2023 winner: 11:22 a.m., Feb. 18.
- The 2022 winner: 1:25 p.m., Jan. 19.
The butterfly inhabits vacant lots, fields and gardens where its host plants, weedy mustards, grow. It's a white butterfly with black dots on the upperside, which may be faint or not visible in the early season. 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.”
P. rapae is emerging earlier and earlier as the regional climate has warmed, Shapiro says. "Since 1972, the first flight of the cabbage white butterfly has varied from Jan. 1 to Feb. 22, averaging about Jan. 20."
In its larval stage, the cabbage white butterfly is a pest of cole crops, including cabbage, cauliflower and broccoli.
Bohart Museum of Entomology
Assisting with the 2025 contest was the Bohart Museum of Entomology, directed by Professor Jason Bond. The 2025 alternative rules stipulated that contestants must collect a live butterfly in the wild, video it, and email the entry to the Bohart Museum at bmuseum@ucdavis.edu, listing the time, date and place.
Statistics since 2010:
- 2024: Art Shapiro recorded the winner at 11:30 a.m., Jan. 29 in West Sacramento, Yolo County
- 2023: Shapiro recorded the winner at 11:22 a.m., Feb. 18 in West Sacramento.
- 2022: No official contest due to the COVID pandemic, but Shapiro recorded his first-of-the-year P. rapae at 1:25 p.m. on Jan. 19 in West Sacramento
- 2021: No official contest due to the COVID pandemic, but Shapiro collected his first-of-the-year at 1:55 p.m. Jan. 16 on the UC Davis campus, Yolo County
- 2020: Shapiro recorded the winner in Winters, Yolo County at 11:16 a.m. on Jan. 30 at the Putah Creek Nature Park.
- 2019: Shapiro collected the winner near the Suisun Yacht Club, Suisun City, Solano County, at 1:12 p.m., Friday, Jan. 25.
- 2018: Shapiro collected the winner in West Sacramento
- 2017: Jan. 19: Shapiro collected the winner on the UC Davis campus
- 2016: Jan. 16: Jacob Montgomery 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
- 2010: Jan. 27: Shapiro collected the winner in West Sacramento
