Our smallest sulphur is unique among southern California pierids in that it feeds on certain members of the Asteraceae family. Palafoxia arida - Spanish needle - is one such aster; Adenophyllum porophylloides - San Felipe dogweed - is another. I've seen it oviposit on Chaenactis stevioides, but it isn't clear that the larvae will feed on this plant (per Gordon Pratt). This butterfly is common in the deserts and flies most of the year. There are seasonal forms of the adult wing coloration, from darker (winter, with shorter photoperiod) to lighter (summer, longer photoperiod).
A dainty sulphur, Nathalis iole, taking nectar along Cactus Spring Trail. August 30, 2019.
Nathalis iole at Rattlesnake Canyon in the Johnson Valley. October 9, 2022.
Same day as above. The scale broom here is a big draw for insects in autumn.
The darker winter form of Nathalis iole. This was at Box Canyon in Anza-Borrego Desert State Park on March 19, 2022.
I watched a Nathalis iole oviposit on Chaenactis stevioides, and got a decent shot of the egg. This was on the Juniper Flats Trail in Joshua Tree National Park on April 30th, 2023.
I lucked upon this chrysalis of Nathalis iole while checking Astragalus palmeri seedpods on Cactus Springs trail on November 26th, 2022. There were San Felipe dogweed plants nearby.
Spanish needle, Palafoxia arida, is a caterpillar food plant of Nathalis iole.
A closer look at the flower of Spanish needle, Palafoxia arida. The use of Asteraceae-family plants by this species of sulphur sets them apart from our other pierids.
And a good look at the flower of San Felipe dogweed, Adenophyllum porophylloides. I believe this is the main host at Cactus Spring Trail.
Nathalis iole was described in 1836 by Boisduval based on a male collected in Mexico. The journal is Histoire naturelle des insectes. Spécies général des lépidoptères, published in Paris. This was before the gold rush brought Pierre Lorquin to California; Lorquin would send to Paris many then-unknown California butterflies for Prof. Boisduval to describe and name.