Caterpillar: Orange-barred Sulphur

Last fall I was excited to find a couple of beautiful yellow and orange butterflies (Orange-barred Sulphurs) flying around the Bahama Senna shrubs in the front yard. Search as I might, though, I never did find a caterpillar. This fall I've seen them flying on several occasions, but they've never settled down while I've had my camera with me. (Seriously, I've never seen so much fluttering and so little landing.) Even though I haven't been able to get a photo of an adult, I have finally found a caterpillar, so I guess things balance out. I was cleaning up the yard and taking down the shutters the morning after Hurricane Matthew passed by, staying politely out to sea but giving us all a healthy scare, when I discovered this bright yellow caterpillar on one of the shrubs:
Orange-barred Sulphur (Phoebis philea). Boca Raton, FL, October 7, 2016.

Orange-barred Sulphur (Phoebis philea). Boca Raton, FL, October 7, 2016.

Calloo callay! This little guy brought a little brightness to an otherwise drab gray day.

New backyard butterfly: Orange-barred Sulphur

Orange-barred Sulphur (Phoebis philea). Boca Raton, FL, November 20, 2015.
I've already mentioned how glad I've been to have the Bahama Sennas I put in last spring (Senna mexicana var. chapmanii). They've attracted my "everyday" sulphur, Cloudless (Phoebis sennae), a nice Sleepy Orange (Eurema nicippe), and now a new butterfly for the yard (one of the only new insects discovered in this windy, windy November), the Orange-barred Sulphur (Phoebis philea):
Orange-barred Sulphur (Phoebis philea). Boca Raton, FL, November 20, 2015.

Orange-barred Sulphur (Phoebis philea). Boca Raton, FL, November 20, 2015.

As soon as I saw it, I knew it was a different butterfly than any of the ones I'd seen before. Its size alone made it stand out; this is Florida's largest sulphur butterfly, even larger than the appropriately named Giant Orange Sulphur (P. agarithe). The cloudless sulphurs I see every day, while not exactly shrimpy, look small compared to this hulking giant. The color also made it stand out. The entire underside (that is, what's visible when it has its wings closed) was "rusty" orange, and the orange was particularly prominent when it was flying. I managed to capture a moderately nonhorrible image of the hindwing orange area, although it's nothing to write home an entire blog post about:
Orange-barred Sulphur (Phoebis philea). Boca Raton, FL, November 20, 2015.

Orange-barred Sulphur (Phoebis philea). Boca Raton, FL, November 20, 2015.

The orange at the base of the female's hindwing is not the "bar" referred to in the name, though. The orange-barred part of the name comes from the male, which has a thick orange "bar" on the forewing (In case you didn't know, in describing an animal, stripes run vertically, while bars run horizontally.):
Phoebis philea, male. Left: upper side. Right: lower side. Museum specimen, Musee d'Histoire Naturelle de Toulouse. Specimen from French Guiana.

Phoebis philea, male. Left: upper side. Right: lower side. Museum specimen, Musee d'Histoire Naturelle de Toulouse. Specimen from French Guiana. Photo by Didier Descouens.

According to almost all of my books, the orange-barred sulphur colonized Florida from the West Indies in the late 1920s.1 According to Cech and Tudor, it is less migratory than our other sulphurs (Cloudless being the "typical"—or perhaps extreme, rather than typical—migratory sulphur, occurring over a wide range at various times of the year.) Like most sulphurs, its larval host plant family (what the caterpillars eat) is the sennas in the genus Cassia (as opposed to the sennas in the genus Senna—plants are awesome!). The caterpillars of the Orange-barred are highly variable green or yellow, but no matter what basal color they have, they have bold markings that make them quite a bit more colorful than the green-with-a-yellow-racing-stripe Cloudless cats:
Orange-barred sulphur caterpillar images from bugguide.net.

Orange-barred sulphur caterpillar images from bugguide.net.

However, I have yet to find one on my property; all of the candidate caterpillars I've found have turned out to be early instar cloudless sulphurs; as they grow, they get greener and greener. Caterpillars of all the sulphurs appear to prefer to eat the flowers, although the leaves will do when there are no flowers present. (And there are rarely flowers present, since there are so many generations of caterpillars, and they all prefer the blossoms, or if those are absent, the buds.)