Orange Sulphur (Colias eurytheme) is a small-medium butterfly, with a wingspan of 1.375 to 2.75 inches. It has a very long season in our local area, February through November. Numbers peak in October. Hosts plants are in the Pea family (Fabaceae), including Alfalfa (Medicago sativa), White Clover (Trifolium repens), and White Sweet Clover (Melilotus alba).
Unusually, caterpillars mostly feed at night. Older caterpillars will first finish one half of the leaf before moving to the other half. The caterpillar, which can be very destructive in Alfalfa fields, is also known as the Alfalfa Caterpillar.
Adults are almost never seen perched with open wings. The wings are typically yellow/orange, but some females are greenish-white. Adults live for just a few weeks.
This butterfly, like all butterflies in the Pieridae family (Whites and Sulphurs), flies endlessly and does not land very often. So it is under-represented in photograph-based databases like iNaturalist. However, Orange Sulphur is slightly more prone to landing than the other butterflies in the Pieridae family on the Garden’s species list.
This butterfly is found only in North America and Central America.
