Citrus Swallowtail Caterpillar and Citrus Swallowtail Butterfly

Australian bird shit caterpillar
Hi Bugman,
I am no entomologist but I like science and looking at it I was thinking: What is that? A bird shit caterpillar !!! Wow, how darwinian !? Searching on the net I discover you have the same in Kansas… I thought you’d be interested to know that we have the equivalent in Australia living on our lemon tree, it’s the citrus thing that triggered my interest. Two bugs adopting the same mimicry eating the same kind of leaves…? It’s more than just a case of co-evolution. And I suspect the butterfly associated to this caterpillar is this gorgeous one that goes up and down and up and down in the hot summer afternoon in our backyard. I have a pic somewhere I’ll try to find it if you are interested. On the pic the caterpillar is in a defensive position, normally the pointy bits are not erected and it looks just like a bird poo. New years greetings from Oz
Olivier Bruge & Peter Young

Hi Olivier and Peter,
Your caterpillar is a Citrus Swallowtail or Orchard Swallowtail, Papilio aegeus. The Butterflies of Australia website has images of the caterpillars and the adults. Your caterpillar is an early instar, and the coloration will change with subsequent molts. We would love to get a photo of the adult butterfly if you are able to send one.

Down under Papilio Aegeus !
Hi Daniel,
Thank you so much for your answer. Here is the pic of the butterfly I was very happy to know that my huntch was right. I love the idea that this beautiful insect comes out of a big poo!! It’s a great evolutionary version of Andersen’s “hugly duckling”. … Have a g’day (as we say here)
Olivier Bruge,
Canberra, Australia.

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