Julia Longwing

The Julia Longwing (Dryas iulia) is a member of the Longwing (Heliconiinae) family of butterflies. Heliconians are widespread throughout tropical regions and include the Longwings (or Heliconians) and the Fritillaries.

Males of the species are bright orange above with small dark markings on their upper wings. Female Julias, like the one pictured to the left, have more obvious and extensive black markings. The Julia Longwing can be found throughout South Florida and strays further north along the Florida coastline in the warmer months. Adult Julias exhibit a feeding behavior called “trap-lining” where the butterfly will visit the same flowers along a route each day in the same order.

Females lay eggs singly on the tendrils of passionvines on which the larvae host. The caterpillars are similar in appearance to larvae of the Zebra Longwing (Heliconius charitonius), Gulf Fritillary (Agraulis vanillae) and Variegated Fritillary (Euptoieta claudia) but each species has a unique color pattern that identifies them. If you find caterpillars on your passionvine in the Central regions of Florida then you are likely looking at one of these four species.

• Gulf Fritillary: Orange with black branching spines. Final instars may have black stripes running down the center back and along each side.
• Zebra Longwing: White with black branching spines.
• Variegated Fritillary: Orange with branching spines and white lengthwise stripes that run along the bases of the spines.
• Julia Longwing: Larvae are variable in color but often black to dark brown with blotchy white lengthwise stripes or markings.

Julia Longwings near the northern edge of the range in the Tampa Bay area and tend to be quite rare in West Central Florida.