Milkweed Butterfly

Milkweed Butterfly

Milkweed butterflies are a subfamily, Danainae, in the family Nymphalidae, or brush-footed butterflies. They lay their eggs on various milkweeds on which their larvae (caterpillars) feed. Historically, this group had been considered a separate family, Danaidae, and the tribes placed herein were sometimes considered distinct subfamilies in the Nymphalidae.

There are some 300 species of Danainae worldwide. Most of the Danaini are found in tropical Asia and Africa, while the Ithomiini are diverse in the Neotropics. Tellervini are restricted to Australia and the Oriental region. Four species are found in North America: the Monarch Butterfly (Danaus plexippus); the Queen (Danaus gilippus); the Tropical Milkweed Butterfly (Lycorea cleobaea); and the Soldier Butterfly (or "Tropic Queen"; Danaus eresimus).

The best known member of this family is the Monarch butterfly. The larvae and the butterflies retain poisonous glycosides from their larval host plant, the milkweed, so they become distasteful to potential predators. These milkweed butterflies (Monarch, Queen, Soldier) eat only milkweeds (Asclepias) as larvae. This highly effective defense strategy shields them against almost all predators that soon learn to avoid these species after attempting to eat them.

Another member known especially for its presence in butterfly greenhouses and live butterfly expositions is the Southeast Asian Idea leuconoe.

The fossil milkweed butterfly Archaeolycorea is known from the Oligocene or Miocene Tremembé Formation of Brazil. It often assigned to tribe Danaini, specifically subtribe Euploeina, but this may not be correct. In any case, it provides evidence that the present family originated more than 20-30 million years ago.