Julia Longwing Butterfly
Family Heliconiidae / Subfamily Heliconiinae (Longwings & Fritillaries) / Species: Dryas julia
Captive live butterflies photographed at the Peggy Notebaert Nature Museum, Chicago IL.

The longwing butterflies have unusually long lifespans and high fecundity rates, which largely result from their augmented diet. Instead of surviving on food stores from the larval stage or solely sipping flower nectar, adult longwing butterflies are avid pollen eaters. This trait makes them eminently suitable for butterfly farming and butterfly gardening. Also, adult longwings may live for several months, much longer than most butterflies.

The longwing butterflies are also known as Heliconians. They are brightly colored butterflies with long forewings. Once placed in their own family, they are now considered closely related to the fritillaries. Larvae of most longwings  feed on passion vines, and this host plant imparts noxious chemicals to the larvae which are carried over to the adult butterflies. This relationship is identical to the monarch butterflies' reliance on its host plant, milkweed, for defense. Predators find these chemicals distasteful and avoid eating the butterflies.
 

The longwings participate in another fascinating behavior known as communal roosting. Circadian communal roosting in butterflies occurs when a number of butterflies gather to rest for the night, typically on a single branch. These communal roosters can be quite numerous and can consist of single specie or a variety of species. Each evening, the air around the roosting site fills with butterflies as they fly back and forth and work to find an open spot on the roost. The whole process takes about an hour to complete because the new arrivals tend to agitate the butterflies that perched earlier. Unless the roosting site is disturbed, the same butterflies will visit that spot night after night. Strength in numbers is one of the benefits of communal roosting for Longwings. Predators dislike the taste of Longwing butterflies, so if a predator eats from the roost it will quickly learn not to do it again, saving the group.