The larvae feed on Teclea tricocarpa, Teclea stuhlmanni, Calodendrum, Citrus, Clausena, Fagara and Toddalia species.

In the early morning and late afternoon adults of both sexes descend from the forest canopy to feed from the flowers of Lantana, Impatiens and Bougainvillea.

It hilltops on granite outcrops and mud puddles.

[4] The Kenyan forms mimic Tirumala formosa, the forest monarch butterfly.

Papilio rex is a member of the dardanus species group.