By Bruce Schuette, MPF’s Vice President of Science and Management
Photo: Adult cloudless sulphur by Bruce Schuette
The epic migration of the monarch butterfly between eastern North America and Mexico is well known. There are other butterflies that migrate too. One of these is abundant on Missouri prairies, open fields, and native plantings in rural, suburban, and urban areas—the cloudless sulphur (Phoebis sennae).
Cloudless sulphurs are active all winter in the very southeastern parts of the U.S.. From spring into summer they’ll move north, breeding and laying eggs as they go. Caterpillars feed on a few plants in the legume family, especially partridge pea (Chamaecrista fasciculata) and wild senna (Senna marilandica). They reach Missouri and keep going north as far as Canada on occasion. As summer comes to an end, many of the current generation of adults will begin moving south, completing their annual migration.
Cloudless sulphurs are the largest of the sulphur butterflies that are regularly found in Missouri, with a wingspan of 1.75 to 2.75 inches. They also have the least amount of dark coloring on their wings, making these big bright yellow butterflies easily recognizable.
As they are preparing for their southern trip, the cloudless sulphurs are putting on quite a show right now. You may see them flitting around the open habitats they prefer, visiting flowers (like the native field thistle, above), and puddling at wet spots.
You can support sulphur butterflies at home by planting their host plants including wild senna and partridge pea. Find suppliers of partridge pea, wild senna, and hundreds of other native plants at MPF’s Grow Native! Resource Guide.