Common Name: Red-Spotted Purple, Red-Spotted Admiral, White Admiral (with white bars) – Named for the red spots on the underside of the wing and the purple upper wings.
Scientific Name: Basilarchia Astyanax, also sometimes called Limenitis arthemis
Potpourri: The Red-Spotted Purple, like many butterflies, has an elaborate defensive scheme against predators. It mimics the Pipevine Swallowtail, whose larvae feed on plants of the birthwort family which contain the chemical aristolochic acid that is unpalatable to predators. Due to the mimicry, predators avoid both butterflies.
Red-Spotted Purple males engage in “puddling,” a congregation of many butterflies on a patch of mineral rich muddy ground, dung, carrion or urine. Using their long proboscises, they extract salts and nitrogen which they form into a spermatophore, a sac containing sperm and nutrients that they pass to the female during mating. The female uses the nutrients during egg production and the pheromones of the spermatophore ward off other would be suitors.
The Red-Spotted Purple (L . arthemis astyanax) and the White Admiral (L. arthemis arthemis) are closely related subspecies that hybridize on the border between their ranges. The former is found in the south and the latter in the north with a mixture in Pennsylvania and New York. A combined name of Red-Spotted Admiral has been adopted by some groups.