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Giant Swallotail Caterpillar - June 26, 2013

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Giant Swallowtail Butterfly (Papilio cresphontes) caterpillar

Bird droppings indeed.  At least that’s what biologists often describe as the appearance of these caterpillars.  (It’s a very big bird that left this calling card!)  I was fighting malaria on my back patio with a gin and tonic and noticed a huge blotch on a citrus leaf.  The citrus plant came up from seeds and had reached about 6 feet in height.  Upon closer examination, I noticed not one but two of these bird droppings on the leaves.

This is the caterpillar of the Giant Swallowtail Butterfly and one of its favorite foods is citrus.  It also likes wild lime (Zanthoxylum fagara) and I have both in the yard and adult Swallowtails are pretty common all year.  As you can tell, it was a pretty windy day when this was filmed. 

What I did not know about the caterpillar is that when threatened, the entomology and nematology department of Institute of Food and Agricultural Sciences at the University of Florida says the caterpillar’s older stages look like snakes and that the inflated thorax may look like a snake’s head.  To continue the mimicry, the caterpillar will evert an osmeterium (two fleshly lobes) that may mimic a forked snake’s tongue.  Apparently the osmeterium produces a very foul odor (can you say bad snake’s breath) rich in terpenes. 

The next day, there were three caterpillars!  Unfortunately, I don’t yet have a photo of an adult but intend to watch to see if any of these pupate and hopefully catch their emergence from their cocoon. 

© Fred Searcy 2017