The Danaus: A less than tasty genus of butterflies

The Danaus genus of butterflies contains twelve species of butterflies that consume milkweeds as caterpillars. Species from this genus are found in around the world including North America, South America, Australia, Africa, Indonesia and Asia. These larvae are uniquely able to digest the toxic milk saps of the milkweed plant. This sap makes the caterpillar and butterfly distasteful to predators.

Danaides are members of the Nymphalidae or brush-foot family of butterflies. The adult butterflies only appear to have 4 legs. The last 2 insect legs are very small and are located near the head of the butterfly.

There are three species of Danaus butterflies found locally in the Tampa Bay area. The Monarch (Danaus plexippus) butterfly is the most common of the trio and is most likely to be seen sipping nectar in your butterfly garden. The less common Queen (Danaus gilippus) butterfly appears a bit darker in color than the Monarch and lacks black stripes on the upper wings. The Soldier (Danaus eresimus) butterfly looks very much like a monarch with a light colored watermark on the lower wing. They are a sometime stray through this area and southern Texas but are more often sighted in South America.

By looking like each other these butterflies reinforce their toxicity to predators. A predator that has eaten a distasteful Monarch is less likely to try a peck of a Queen or a Soldier. These three species are clever mimics utilizing Mullarian mimicry to reinforce the warning colors and distasteful qualities of several related species, gaining all three species more protection from predators.

Local Mimic: The Viceroy butterfly (Limenitis archippus) mimics the common Danaid butterflies and is able to gain protection by looking like them. Predators who have tried to eat a toxic Monarch or Queen are less likely to tangle with a butterfly that looks a lot like them. Viceroys are also bad tasting because they eat willow and are able to sequester the Salicylic acid from the leaves of the plants. This chemical makes the caterpillars and butterflies very bitter to taste and likely to upset the stomachs of predators.

Danaus and the Danaides: In Greek mythology, Danaus or Danaos (Greek for “sleeper”) was the twin brother of Aegyptos, the mythical king of Egypt. Aegyptos had 50 sons and commanded that they marry the 50 daughters of Danaus. Danaus and his daughters, known as the Danaides, fled to Argos and were pursued by the sons of Aegyptos. Forced into marriage to protect Argos from the aggression of the sons of Aegyptos, all but one of the Danaides murdered their new husbands on their wedding night at the instruction of their father. The story of Danaus and his daughters is the subject of a play by Aeschylus entitled The Suppliant Maidens.