Orange Sulphur

One of 13 Coliadinae (sulphur subfamily) species found in Ontario, Orange Sulphur is also known as the Alfalfa Butterfly. As with many Sulphurs, eurytheme's wing pattern and coloration is sexually differentiated. Although it is a resident representative of this genera, C. eurytheme may also be migratory. In southern fields of Alfalfa and clovers, Orange and Clouded (C. philodice) Sulphurs can become quite numerous and are considered agricultural pests.

Identification: Males of Orange Sulphur have bright orange upper wings with solid black borders. Spring generation may be smaller with yellow top wing having only a small patch of orange shading in the middle of the wings and a narrower black border. Females have yellow spots in the black border and white females are commonly encountered. Both sexes have a black spot on the top and bottom forewing, and an orange spot on the top hindwing. Also, the undersides of both fore and hindwings have a row of small brown dots near the margin and, on the hindwing, a pink rimmed silver spot. Wingspan: 34-55 mm.

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.

Posted in: O,Orange Sulphur,Pieridae