Julia Longwing Butterfly – 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.
Family Nymphalidae – Brushfoots or brush-footed butterflies encompass approximately 3,000 species worldwide, of which 160 or so live in or visit North America. This is a very diverse family of butterflies, and they occur everywhere except the polar ice caps. Their unifying characteristic is the reduced forelegs of both males and females. These vestigial forelegs are nearly useless for walking and give rise to the family’s common name.
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