Pontia beckerii

Becker's White

In southern California, this is a butterfly of the deserts, whether at Yaqui Well among the bladderpod, at Joshua Tree National Park where Prince's Plume grows, or at Scissor's Crossing among the wild mustards. At Cactus Spring Trail, I've seen it oviposit on Sisymbrium orientale, one of the only viable mustards left in the heat of mid-May. Two weeks earlier, I saw a female ovipositing on bladderpod (Isomeris arborea) at the Whitewater Preserve, and that is the plant - a member of the caper family - most strongly associated with beckerii in my mind.

Becker's White flies in multiple broods much of the year. It is closely related to Pontia chloridice a Eurasian butterfly. In fact, James Scott (1986) lists it as subspecies beckerii under Pieris chloridice (he also has protodice and sisymbrii under the genus Pieris).

Becker's White - Pontia beckerii
This is Becker's White nectaring on host Bladderpod at Yaqui Well in Anza-Borrego Desert State Park, January 17, 2006.
Those that emerge early in the year are more darkly marked. (This date was an early record for California.)
Becker's White - Pontia beckerii
Another early dark Becker's White, this one a female from Sentenac Canyon in Anza-Borrego Desert State Park, March 1, 2009.
Becker's White - Pontia beckerii
A male Becker's White, Yaqui Well, October 11, 2005. Males are more lightly marked than females dorsally.
Becker's White - Pontia beckerii
Another male Becker's White at Yaqui Well on the same day as the male above.
Becker's White - Pontia beckerii
A female from Yaqui Well. February 11, 2008.
Ovipositing female Becker's White butterfly - Pontia beckerii
Followed this female as she oviposited on the bladderpod plants at Whitewater Preserve in Riverside Co. on April 30, 2017...
Egg of Becker's White - Pontia beckerii
...and here is an egg on a flower bud.
Egg of Becker's White - Pontia beckerii
I watched a female ovipositing on Sisymbrium orientale along Cactus Spring Trail not far from the parking lot. I took this photo of the flower head, and only noticed the egg when I zoomed in on it after I got home. May 13, 2017.
Egg of Becker's White - Pontia beckerii
Found this tiny caterpillar of Pontia beckerii on Cactus Spring Trail. I believe it was Sisymbrium orientale. April 22, 2019.

©Dennis Walker