Later that day, another Guest Relations staffer watched the caterpillar pupate! By the time word travelled to me, the pupa looked like this:
Yellow pupa on Dudleya
When I came into work on Tuesday morning, the pupa had changed color! I took more pictures and went back to my office to identify it.
The pupa belongs to a butterfly regularly seen in and around Los Angeles, the Cloudless Sulphur, Phoebis sennae. The Cloudless Sulphur belongs to the Pieridae butterfly family, which includes White, Sulphur, and Orange-tip butterflies. The most common butterfly in this family is the Cabbage White, which flies year round in our area and is a pest on vegetables such as cabbage, kale, and broccoli. In contrast the caterpillar of the Cloudless Sulphur feeds on cassia plants (genus Senna) and is often seen in our local deserts where the two California native species in this genus grow naturally. The altered nature of Los Angeles is such that non-native cassias are now common all over our area. They've been planted in various places like your neighbor's backyard, your local park, and even in the North Campus. The bus stop where Jany found the Cloudless Sulphur caterpillar is only 20 feet away from a few feathery cassias, Senna artemisioides, which were recently planted in the North Campus!