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What is it: Frangipani moth

A friend sent me this photo last month with the explanation, “Found this outside our house–friendly?”

Pseudosphinx tetrio larva. Image credit: J. Parsons, used with permission.

My friend lives in Pembroke Pines, FL and the startlingly colored and rather large creepy-crawly she found is a frangipani moth caterpillar, Pseudosphinx tetrio. Frangipani moths, also known as the tetrio sphinx, are common moths in the American tropics and sub-tropics and occur less frequently in South Florida. Frangipani moth caterpillars feed on frangipani tree leaves and other plants in the dogbane family (Apocynaceae). Adults are an unremarkable drab greyish-brown color but the caterpillars are distinctive for their size and aposematic red-yellow-black coloration.

Aposematism is an adaptation to avoid predation. Aposematic organisms typically do not taste good to predators or are poisonous, and their striking colors are a warning signal for predators to avoid eating them. Frangipani moth caterpillars are unharmed by the poisonous latex sap commonly found in plants from the dogbane family but their diet makes them distasteful to predators. You may see frangipani moth caterpillars in South Florida from July through September, especially if you are around frangipani trees or angel’s trumpet. These hungry caterpillars can eat three frangipani leaves per caterpillar per day, so your frangipani trees may be looking bare right now if you had these in your yard this summer. Frangipani trees usually aren’t harmed by the caterpillars, even if all their leaves are gone, so spraying an insecticide isn’t necessary. You can remove the caterpillars by hand if they bother you. They aren’t dangerous, but they do have strong jaws and may nip you.

We’re at the end of their season so you may not see any right now. Did these impressive larvae cross your path this summer?