The Gulf fritillary or passion butterfly (Dione vanillae or Agraulis vanillae in other taxonomies) is a bright orange butterfly in the subfamily Heliconiinae of the family Nymphalidae. That subfamily was formerly set apart as a separate family, the Heliconiidae. The Heliconiinae are "longwing butterflies", which have long, narrow wings compared to other butterflies. Dione vanillae is most commonly found in the southern areas of the United States, specifically in many regions of Florida and Texas. Gulf fritillaries have a chemical defense mechanism in which they release odorous chemicals in response to predator sightings. As a result, common predators learn to avoid this species. Pheromones play a critical role in male-female courtship behaviors, with male gulf fritillaries emitting sex pheromones that contribute to mate choice in females. The scientific name Papilio vanillae was given to the gulf fritillary by Carl Linnaeus in 1758, based on a 1705 painting by Maria Sibylla Merian (The Metamorphosis of the Insects of Surinam, Plate XXV), which shows the adult and caterpillar of the gulf fritillary on a vanilla orchid, Vanilla planifolia. However, it is now known that the gulf fritillary caterpillar does not use the vanilla plant. The species was moved to the genus Agraulis in 1835 by Boisduval & Le Conte. A phylogenetic analysis reported in 2019 placed Agraulis as a sub-genus of Dione.
Description In its adult form, the gulf fritillary is a medium-sized butterfly that has extended forewings and a wingspan range of 6.5 to 9.5 cm. This butterfly exhibits sexual dimorphism as females are typically distinctively larger in size than males. The underside of the wings is brown and speckled with silvery white dots. In contrast, the top surface layer of the wings is deep orange in color with black streaks running across. In addition to the size difference between the two sexes, females are usually darker in color and are more marked with black streaks as compared to the males.
Geographic range Gulf fritillaries are found from the southernmost United States (Florida and Georgia to Texas and California), and throughout the Americas as far south as Argentina. They have also been introduced to Hawaii.
Habitat Gulf fritillaries are found in open habitats, like in moderately sunny areas near open grasslands, parks, and woodlands. Gulf fritillaries are also commonly seen in local butterfly gardens across the U.S.
Host plants The caterpillar food plants--also called the host plants--for gulf fritillaries are members of the genus Passiflora. The adult butterflies use nectar from many flowers, including Lantana plants. The Passiflora host plants are frequently called passion vines; in some Texan counties where this butterfly's population is high, gulf fritillaries will feed on specific species such as Passiflora lutea and Passiflora affinis. These passion vine plants are suitable host plants as they provide a good structure for larval host habitats which enables young populations of gulf fritillaries to be sufficiently nurtured and protected. The role of host plants is also integral to the oviposition of gulf fritillaries, as the female butterflies lay their eggs on or near the host plant.
Propagation
Oviposition The process of oviposition in gulf fritillaries begins with the female butterfly flying low and slightly above the vegetation (most likely the typical host plants like Passiflora incarnata or Passiflora lutea) and lasts until the female pauses above an individual plant. Then, the female makes contact with the host plant by landing; the female then deposits an egg to complete the process of oviposition. The driving factor behind what causes the female to oviposit on or near the host plant is most likely due to the certain chemical composition of the specific genus of the host plant. Once the female recognizes the chemical composition (by using the antennae), the female will oviposit.
Life cycle
Egg Eggs are small and spherically shaped; the female gulf fritillary lays the eggs individually one by one on or near the host plant. Typical host plants include several species of the genus Passiflora. The eggs are initially yellow in color after deposition by the female, and they gradually turn a brownish red color over the course of the next 24 hours. The average duration of the egg stage in the life cycle for gulf fritillaries is roughly between three and five days depending on the temperature of the environment. Eggs are usually found on the upper surfaces of the leaves of the host plant, but some can be found on the underside of leaves as well.
Larva
In appearance, the larvae are dark orange with small black spines protruding outward from the body. The larval stages of gulf fritillaries include five instars, each with a varying timeframe. After the eggs hatch, the new larvae eat the egg casings for food. Eventually, the larvae will transition either to consuming other eggs or parts of the host plant for nourishment. Throughout the first three instar stages, the larvae primarily consume the leaves and feed away from the leaf margins of the host plant. How much of the leaf and how deep into the layers the larva will eat depend on the type (i.e. thickness or thinness) of the leaf in question. Throughout the last two instar stages, the larvae mainly consume the leaves and feed at the leaf margins. Throughout this food acquisition process, the degree to which a specific leaf is eaten before it is abandoned in favor of another newer leaf largely depends on whether food is in plentiful or scarce supply. The average duration of the larval stage is between 11 and 16 days depending on the temperature.
Pupa In form and appearance, the pupae of gulf fritillaries are not recognizably uniform, but rather can vary in both coloring and physical size. The average duration of the pupal stage in gulf fritillaries is roughly between 7 and 12 days depending on the temperature of the environment. Colder temperatures are associated with a longer time frame whereas warmer temperatures are associated with a shorter time for pupal development.
Metamorphosis
… excerpt ends here. Continue reading the full article.
