Another monarch imposter in NorCal gardens

The gulf fritillary is often mistaken for a monarch butterfly. (Courtesy Dr. Shapiro via FreeClipartPictures.com)

Gulf fritillary seeks its favorite plant: Passion flowers

By Debbie Arrington

This butterfly has a passion for passion flowers.

Just as monarchs must have milkweed, the gulf fritillary is dependent on Passiflora, the passion vine. And like the painted ladies, this orange-and-black butterfly is often mistaken for the vanishing monarch.

Butterfly expert Dr. Art Shapiro of UC Davis often gets calls or emails about misidentified fritillary sightings.

"The gulf fritillary has silver spots, but it's a big orange and black butterfly, too," he said. "Unless people notice the silver spots, they think it's a monarch, too."

Shapiro notes that the gulf fritillary was nonexistent in the Sacramento area for decades after a hard frost in the 1970s killed all the available passion vines as well as overwintering butterflies.

"It's a subtropical species that likes to eat a tropical plant; there are no native passion flowers in California," he explained. "It's not adapted at all to our area. It got down to 21 degrees and wiped out the whole population."

Gulf fritillary butterflies started showing up again about 10 to 13 years ago, he estimated. They've been spotted in Davis, North Sacramento, Rancho Cordova, West Sacramento, Suisun, Fairfield, Folsom, south Sacramento and several other spots. 

How the first gulf fritillary arrived in California is a mystery. As its name implies, it prefers the Gulf of Mexico.

"The first one was identified in Southern California in 1875," Shapiro said."It must have come from somewhere back east."

One was spotted in the Bay Area in 1908, but these butterflies didn't really move in until the 1950s. Since then, a large colony has made Berkeley its year-round home. 

A sure sign of happy fritillary is a passion vine with chewed-up leaves.

Shapiro recalled a passion vine that grew behind a Davis restaurant. "It was a big vine and every leaf was eaten," he said. "Downtown Davis was full of gulf fritillaries for weeks."

For more on butterflies: http://butterfly.ucdavis.edu/