The Citrus Swallowtail Caterpillar

CandideSA
Published on November 7th 2019
8
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. Even though the butterfly is a delightful garden visitor, the citrus-loving caterpillar might not be as favoured.

Citrus Swallowtail caterpillars

Caterpillars are very often found munching on citrus trees and other species in 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 green plant
Photo @AstridVermeulen
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 and/or sprinkle diatomaceous earth on the leaves.
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

Egg:
Young caterpillar:
Pupa
Mature caterpillar:
Comparison post:
Butterfly:

Common hosts

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