- Author: Kathy Keatley Garvey
It's what I've always wanted to see on Christmas Day.
On Dec. 25, we rarely see any insects--probably because we aren't looking for them. But a butterfly? And a butterfly laying an egg?
I took an image of a Gulf Fritillary butterfly (Agraulis vanillae) laying an egg in west Vacaville (Solano County) on Christmas Day. She fluttered around a frost-bitten, caterpillar-eaten passionflower vine (Passiflora) as the temperature held steady at 65 degrees.
Then the butterfly dropped down, extended her abdomen, and laid an egg. A tiny yellowish egg, right in the middle of dozens of caterpillars and chrysalids. Somehow or another, these immature stages managed to survive our extended frost, when the mercury dipped to 22 degrees.
I told butterfly expert Art Shapiro, distinguished professor of evolution and ecology at UC Davis, about the egg-laying butterfly. Not so coincidentally, he was searching for adult butterflies in Vacaville today (temperature, 70 degrees), but didn't see any.
Shapiro, who monitors the butterflies of Central California and posts information on his website, sounded the alarm about the comeback of these spectacular orange-red butterflies several ago. It was in September 2009 that he excitedly announced the re-appearance of the Gulf Frit after its four-decade absence in the Sacramento metropolitan area, and its three-decade absence in the Davis area.
The larvae or caterpillars of the Agraulis vanillae feed on the leaves of the passion flower vine; they eat "many but not all species of the genus Passiflora," Shapiro says. "There are no native members of this genus in the state of California, but several are widely cultivated in gardens."
It's a tropical and subtropical butterfly with a range that extends from the southern United States all the way to central Argentina. No one knows exactly when the first Gulf Frit first arrived in California, but "it was already in the San Diego area by about 1875," Shapiro said. It was first recorded in the San Francisco Bay Area around 1908.
The showy butterfly colonized both south Sacramento and the Winding Way/Auburn Boulevard area in the 1960s but by 1971 it "apparently became extinct or nearly so," recalled Shapiro, a Davis resident since 1971.
Now we know that at least some Gulf Frits survived the freezing temperatures--just when a setback threatened the comeback.