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The Citrus Swallowtail Caterpillar

Published on March 27th 2021
A close up of a green plant
The Citrus Swallowtail, Papilio demodocus is a beautiful, large black and pale-yellow butterfly that can regularly be seen in South African gardens. This delightful garden visitor
A colorful butterfly on a flower
Citrus Swallowtail Butterfly. Photo @dawnmacd.

Citrus Swallowtail caterpillars

The caterpillars are very often found munching away at leaves on citrus trees and other species within the Rutaceae family. At first glance, you might not even notice the little caterpillar as it is perfectly camouflaged as a bird dropping with its black, yellow and white colouration. As it matures, however, it turns into a uniform green.
A close up of a reptile
Photo @marietjie
A close up of a swallowtail butterfly caterpillar
Photo by @doidgea.
Another very curious defence adaptation includes the osmetrium - a forked, orange-coloured organ that protrudes from just behind the caterpillar’s head and gives off a scent that would make any potential predator lose its appetite. The osmetrium has given the caterpillar the common name ‘Orange dog’.
Caterpillars take approximately one month to mature and three generations can be seen every year - at autumn, spring and summer.
A close up of a green plant
Photo @greenmom.
The female lays individual eggs on the underside of leaves on a wide range of food plants, not just citrus, although these are a firm favourite. The eggs will take about six to seven days to hatch.

Caterpillar control

Citrus Swallowtail caterpillars can be a pest of many citrus species and can cause considerable damage to young trees. Well-established trees usually survive an infestation and the damage done by this caterpillar is generally minor. The little bit of damage is well-worth the delightful sight of the butterflies in your garden.
Citrus Swallowtail Butterfly
Photo @TalithaCherry
If there is a very large infestation and they are causing considerable damage to the tree, simply pick the caterpillars off.
The eggs and larvae are also parasitized by a number of wasp species and the larger caterpillars make a delicious treat for birds.

Check out these away community posts of the Citrus Swallowtail in all its stages



There is lots of Citrus Swallowtail butterfly - Papilio demodocus activity around my lemon trees but very few orange dog catapilars. This is because parasitoidal wasps are laying their eggs in the butterflys eggs. The picture has an egg with a grey spot which shows the tiny wasp as laid its egg. @ArneStander

Young caterpillar:
Mature caterpillar:
Comparison post:

Common hosts