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The Orange-Barred Sulphur on Cassia (Senna)

Lindheimer’s senna, Senna lindheimeriana, a member of the pea family (Leguminosae or Fabaceae), and similar Cassia (Senna) species such as C. alata or Candlebush, C. occidentalis, C. bicapsularis, C. fistula, C. marilandica, C. corymbosa, as well as members of the genera Pithecellobium (subfamily Mimosoideae) and Caesalpinia (Bird of Paradise), are host plants for sulfur butterflies that include the cloudless sulfur, Phoebis senne, the large orange sulfur, P. agarithe, and the orange-barred sulphur, P. philea (Lepidoptera: Pieridae).  Some of these host plants such as the Tree Senna (C. corymbosa), Candle Bush (C. alata) and Desert Bird of Paradise (C. gilliesii) may be available through the nursery industry.

Both the caterpillar stages and adults of the orange-barred sulphur are dimorphic (types of polymorphism), meaning that they each have two forms:

Caterpillars (developing larval stages) are usually green with black stripes for those that feed on leaves. However, those that feed on yellow flowers are yellow with black bands on each body segment. This dimorphism helps caterpillars hide from predators, using their dimorphism to mimic plant parts.

Adults or butterflies of this species are also sexually dimorphic, with the male having bright yellow wings with a red-orange bar and the hind wing having a red-orange margin. The female color ranges from orange to white with darker spotting along the forewing margins and a broad red-orange band on the margin of the hind wing.

Fig. 1. Orange-barred sulphur developmental stages, with the flower feeding yellow caterpillar form pupating (top row) and leaf-feeding caterpillar pupating (bottom row) and adult male (top right) and female (bottom right) stages of this butterfly species (See larger image).


I thank Dr. Mark Muegge for valuable input and review of this web page.