Chlosyne californica
California Patch
This is a spring flying desert butterfly for the most part, but with summer rains it can be common later in the year and even abundant. In September, 2022 - a year with good summer rainfall in the deserts - I saw at least a thousand of these in the Mojave Desert Preserve. This butterfly can have varying amounts of orange and dark brown on the dorsal side of the wings. California patches resemble bordered patches somewhat but are easy to distinguish, and the amount of variation in the wings is much greater in bordered patches. In the places I tend to visit, this butterfly seems to be a "boom or bust" species, barely seen some years and ubiquitous others, no doubt depending on desert rains. The host is Bahiopsis parishii, Parish viguiera, which is an aster of the deserts. Females lay their eggs on the underside of leaves of the host plant, and the spiny caterpillars are gregarious.
At Cottonwood Spring in Joshua Tree National Park. March 30, 2009.
California patches were fairly common at Horsethief Creek and along Cactus Spring Trail on September 20-21, 2013, and they were the most common butterfly taking nectar on yellow roadside composites at Scissors Crossing on Sept. 28th. This photograph is from Scissors Crossing.
Chlosyne californica, Cactus Spring Trail, September 20th, 2013.
Chlosyne californica, same hike as above.
Here's a caterpillar of Chlosyne californica on the larval food plant Bahiopsis parishii. These looked like third instars to me. This was at Joshua Tree National Park, October 2, 2022. Note the characteristic feeding damage on the leaves, which can help you find the larvae.
This caterpillar is the final instar, not long before pupation in the spring. I was in Plum Canyon at Anza-Borrego Desert SP on March 11, 2024 and found a couple of them.
Another one in Plum Canyon a few weeks later, on March 28th, 2024. These overwinter as mid-instar caterpillars and resume feeding in the spring, then pupate and begin the flight. A few were on the wing on this day.
W.G. Wright named this butterfly (as Synchloe Californica) in 1905, with a typically-vague locality: the Colorado Desert.
J.W. Tilden designated a lectotype in this 1975 paper. His description of his task in working with Wright's text is interesting.
©Dennis Walker
