Papilio demodocus, the citrus swallowtail or Christmas butterfly, is a swallowtail butterfly which commonly occurs over the entirety of sub-Saharan Africa, including Madagascar, besides the southern Arabian Peninsula. The caterpillars feed on various native plants of especially the family Rutaceae, but have also taken to the leaves of cultivated citrus trees.
Citrus swallowtails pass through approximately three generations per year.
Eggs
Female butterflies lay their eggs singly on citrus leaves. After about six days, the egg hatches into an immature larva.
Immature larva
The immature larvae are black, yellow, and white with spikes. Their coloration provides effective camouflage, as they resemble bird droppings. They grow to a length of 10 or 15 mm before changing into mature larvae.
Mature larva
Mature larvae are green with white or pink markings and eyespots. They grow to a maximum length of about 45 mm.
Mature caterpillars lack the camouflage of their immature state. Instead, when threatened by a bird or other predator, they produce a forked, orange-coloured organ known as an osmeterium. The organ emits a strong smell which acts as a discouragement to the predator. The larvae are sometimes known as 'orange dogs'.
Pupa
The caterpillars attach themselves to branches with silk, transforming into pupae. They remain in the pupal form for two to three weeks before emerging as adults.
Adult
Adult butterflies have black and yellow markings with red and blue eyespots. Female butterflies tend to be larger than males.
As with most butterflies, various predators, parasitoids and diseases attack Papilio demodocus, so that integrated pest management is generally the most rational approach to control of infestations, paying due attention to avoiding destruction of the populations of enemies. In particular parasitic wasps in the family Encyrtidae, such as some species of the genus Ooencyrtus develop in Papilio eggs. Other parasitoidal wasps in families such as Chalcididae and Braconidae (for example genus Apanteles) attack the larvae, and Pteromalidae (for example genus Pteromalus) are parasitoids of the pupae. Predatory insects such as certain Heteroptera, in particular Reduviidae known as assassin bugs, and some Pentatomidae attack the larvae, and certain Mantodea such as genus Sphodromantis attack both larvae and adults.
