The Queen (Danaus gilippus) butterfly is fairly common here in Tucson, Arizona, and it is extremely fond of Mule's Fat or Seep-willow (Baccharis salicifolia) flowers.

The Queen is a close relative of the Monarch (Danaus plexippus) butterfly, and both of their ventral (lower) wing surfaces, visible when the wings are closed, are somewhat similar. However, when the Queen opens its wings to reveal its dorsal (upper) wings surfaces, the obvious difference between the two butterflies is revealed.

Unlike Monarchs with their boldly black-veined dorsal wing surfaces, those of Queen butterflies are mostly solidly colored and only faintly veined.

The Queen is very similar to another closely related butterfly, the Soldier (Danaus eresimus), except that the Queen butterfly has more white spots on its forewings.

The sexes can easily be determined because male Queens like this one have black scale patches on the dorsal side of their hindwings.

Like those of Monarch butterflies, the larvae of Queen butterflies feed on various species of poisonous milkweeds. The larvae accumulate the milkweed toxins, and as a result both they and the adult butterflies are quite poisonous. Birds will avoid these poisonous orange (or rust), black and white butterflies and any other butterflies with similar markings like the deceptive, non-poisonous Viceroy (Limenitis archippus).