Description

The Gulf fritillary is the state butterfly of Louisiana. Despite the common name, this species is not a true fritillary, although it is a member of the same family (Nymphalidae). The Gulf fritillary is in a different subfamily of mainly tropical butterflies (Heliconiinae), known as the longwings. Adults are medium‑sized butterflies typically measured at 65 mm to 95 mm in wingspan. The top side of the wings are vivid orange with scattered black spots. The central cell on the forewings contains three white spots outlined in black. The underside of the wing surfaces are brown and marked with elongate, metallic silver spots. Adult bodies are striped orange and white. Adults slightly differ in appearance depending on sex (sexual dimorphism). Females can be distinguished from males by their larger size and their slightly darker coloration with more black markings.

Larvae are cylindrical, predominantly orange in color, with black or purple stripes running the length of the body. They are covered with rows of distinctive black spines. Despite their appearance, the spines are soft and do not contain venom. Larvae range from 1 cm to 4 cm in size. Freshly deposited eggs are yellow and spherical. After 24 hours of being deposited the eggs turn reddish brown. Pupae are dark brown, resembling a shriveled leaf hanging on a stem.

The species was originally described by Linnaeus in 1758 as Papilio vanillae. The taxonomy has undergone several taxonomic changes over time. It was later moved to the genus Agraulis in 1835 as Agraulis vanillae. Recent genetic and taxonomic work has demonstrated that Agraulis is nested within the subgenus Dione. Thus, some references use the name Dione vanillae for the Gulf fritillary. To make matters worse, recent research based on molecular and morphological data has resulted in the species group being split into eight distinct species. The species occurring in Louisiana and the surrounding region is now called Agraulis incarnata.

The Gulf fritillary species complex is primarily found across the southern United States to California and was introduced in Hawaii and various other Pacific islands. Vagrants are sometimes found far north of the normal range. Two other longwings can be found in Louisiana. The Julia longwing, Dryas iulia, is less common in Louisiana but may be found in the summer. It possesses light orange wings outlined in black. The zebra longwing, Heliconius charithonia, is also less common to Louisiana but sightings have been confirmed, possibly as a result of intentional releases by butterfly enthusiasts. It is easily identified by its jet-black wings with white stripes. Agraulis incarnata nigrior is a subspecies of Agraulis incarnata that can be found in neighboring states but has not been reported in Louisiana. It can be distinguished from the Louisiana form by the noticeably heavier black markings. No other butterfly species in Louisiana possess the combination of orange wings and bright silver markings. Eighty species and over 400 species of Heliconiinae are described in the world, but these numbers are likely to change as additional research using molecular data is completed.

Locally there are butterfly species that closely resemble Gulf fritillary. The monarch, Danaus plexippus, is similar in color but easily recognizable by its darker orange wings and bold black veins. The viceroy, Limenitis archippus, looks like a monarch but has a distinct black band across the hindwings. Neither species have the bright silvery spots found on the underside of Gulf fritillary wings.

Life cycle

Gulf fritillary undergoes four developmental stages, as with all insects having a complete (holometabolous) metamorphosis. These include egg, larva, pupa and adult. Eggs are laid on several species of the genus Passiflora (passionflower vines), the only host plant of the Gulf fritillary. Eggs are laid on multiple locations on the plant. Depending on temperature, eggs can take between three and five days to hatch, with longer developmental times during cooler conditions. Once emerged, larvae consume their eggshell and sometimes other unhatched eggs in the area. Larvae in the first few instars feed on new leaves and tend to stay away from the leaf margins. As the larvae grow, they become less picky and will generally eat whatever is in sight. Larvae undergo five instars before pupating. Gulf fritillary larvae generally take 11 to 16 days to mature. To pupate the larvae attaches to a branch with a dollop of silk, forming a J with its body. The pupa (also called chrysalis) forms and remains stationary for five to seven days. The chrysalis turns slightly clear, revealing the black wing venation, just prior to adult emergence. After emergence adults typically spend two to four weeks feeding on nectar and searching for mates.

Gulf fritillaries have an interesting mating strategy. Males locate females perched on plants. The male flutters in front of the female for a while, and release pheromones from glands on the abdomen. The female either accepts or declines based on these chemical cues. Upon acceptance, the male puts his head next to the females and engages in a wing clap display. During the display, the antennae of the female is placed between the male’s wings. Once the display is over, he initiates mating. While mating, the male transfers extra nutrients to the female for use during embryonic development. This is known as a nuptial gift.

Ecological Importance

Gulf fritillary larvae are important in the control of passionflower plants, which can be invasive. By feeding exclusively on passionflowers, larvae help control the plant’s aggressive nature and prevent it from overpowering other native plants. Gulf fritillary adults are vital pollinators for various flowering plants. Adults can be found in pollinator gardens and open fields foraging for nectar.

References

Arbogast. R.T. 1965. Biology and Migratory Behavior of Agraulis vanillae (L.) (Lepidoptera, Nymphalidae). University of Florida Dissertation. 97 pp.

Bug Guide. Species Agraulis incarnata - Gulf Fritillary - Hodges#4413. (accessed 10 March 2026).

Cicconardi, F., E. Milanetti., E.C. Pinheiro de Castro., A. Mazo-Vargas., et al. 2023. Evolutionary dynamics of genome size and content during the adaptive radiation of Heliconiini butterflies. Nature Communications. 5620.

Daniels, J.C. 2009. Gulf fritillary butterfly, Agraulis vanillae (Linnaeus) (Insecta: Lepidoptera: Nymphalidae). University of Florida. IFAS Extension. EENY 423.

Nunez, R. K.R. Willmott., Y. Alvarez., J.A. Genaro., et al. 2022. Integrative taxonomy clarifies species limits in the hitherto monotypic passion-vine butterfly genera Agraulis and Dryas (Lepidoptera, Nymphalidae, Heliconiinae). Systematic Entomology 47: 152-178.

Rutowski. R.L., and J. Schaefer. 1984. Courtship Behavior of the Gulf fritillary, Agraulis vanillae (Nymphalidae). Journal of the Lepidopterists’ Society 38: 23-31.

Shapiro. A.M. 2008. Book Review of Chrysalis: Maria Sibylla Merian and the secrets of metamorphosis. Journal of the Lepidopterists’ Society. 62: 1: 58-59.

Zhang. J., Q. Cong., J. Shen., P.A. Opler., and N.V. Grishin. 2019. Changes to North American butterfly names. The Taxonomic Report of the International Lepidoptera Survey 8: 5.

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Gulf fritillary adult underside showing silver markings. Photo by iNaturalist user dr_q, Creative Commons 4.0

Gulf fritillary adult dorsal view. Photo by iNaturalist user Mary Keim, Creative Commons 4.0

Gulf fritillary larva. Photo by iNaturalist user deefulton, Creative Commons 4.0