Complete Guide To The Clouded Sulphur Butterfly

How To Identify Clouded Sulphur Butterflies

• Wingspan: 1.4 – 2.0 inches (3.6 – 5.0 cm)
• Clouded Sulphur butterflies can be hard to identify for two reasons:
  • Males and females are sexually dimorphic; they look different from each other.
  • Adults are “seasonally variable”; their appearance varies slightly with temperature:
    • Spring and fall adults are small and greenish-yellow (Pyle 1981).
    • Summer adults are large and bright yellow butterflies.
• Above:
  • Males have bright sulphur yellow wings with sharply defined, solid black borders.
  • Females can be either yellow or white with yellow-spotted black borders.
  • Both sexes have a black wing spot on their forewings.
  • Hind wings have an orange spot in the center.
• Below:
  • Green-yellow overall with a faint row of dark spots.
  • Male forewings show a single black spot.
  • Female forewings may have a small, pinkish wing spot.
  • Hind wings have two spots each; one large and one small. Both spots are silvery and surrounded by thin, red rims.
  • Pink wing fringe.
  • Hind wings have a widely spaced single row of tiny brown spots.
• Clouded Sulphurs almost always close their wings when they land.
• Clouded Sulphur butterflies (Colias philodice) sometimes mate with Orange Sulphur butterflies (Colias eurytheme) (Opler and Malikul 1992).
  • These two yellow butterflies look almost identical and their ranges and food plants overlap. In fact, it can be very hard for humans to tell the two types of yellow butterflies apart in real life.
  • The butterflies themselves don’t really have this problem. Male Clouded Sulphur butterflies produce special chemicals called pheromones. Orange Sulphurs don’t make the same chemicals (Grula et al. 1980). Females of each species identify males of their own species by how the males smell.

Clouded Sulphur butterfly Colias philodice labelled with field marks that identify the species. Yellow butterfly. Insect. Photograph taken by the author. Copyright © 2024 Now I Wonder. All rights reserved.