Alternate name: Alfalfa Butterfly
Family: Pieridae, Whites and Sulphurs view all from this family
Description The Orange Sulphur (Colias eurytheme), also known as the Alfalfa Butterfly and in its larval stage as Alfalfa Caterpillar, is a butterfly of the family Pieridae, where it belongs to the "yellows and sulphurs" subfamily Coliadinae. It is found throughout North America from southern Canada to Mexico, but is absent from the central and southeastern USA.
C. eurytheme belongs to a lowland group of clouded yellows (or as they are known in North America, "sulphurs"), Colias. Other members of this lineage including the Common or Clouded Sulphur (C. philodice) and Colias eriphyle and Colias vitabunda that are often included in C. philodice as subspecies.
Hybridization runs rampant between these, making phylogenetic analyses relying exclusively on one type of data (especially mtDNA sequences) unreliable. Therefore little more can be said about its relationships, except that it is perhaps closer to C. (p.) eriphyle than generally assumed, strengthening the view that the latter should be considered a good species.
The Orange Sulphur's caterpillars feed off various species in the pea family (Fabaceae) and are usually only found feeding at night. Occasionally this species multiplies to high numbers, and can become a serious pest to Alfalfa (Medicago sativa) crops.
Dimensions 1 5/8-2 3/8" (41-60 mm).
Habitat Canyons & caves, Cities, suburbs & towns, Freshwater swamps, marshes & bogs, Grasslands & prairies, Meadows & fields, Scrub, shrub & brushlands, Shorelines & salt marshes.
Range Eastern Canada, New England, Great Lakes, Mid-Atlantic, Western Canada, Southwest, Plains, Rocky Mountains, Northwest, Texas, Southeast, Florida, California.