This is the frangipani hornworm moth also known as the giant gray sphinx moth (Pseudosphinx tetrio). It is the biggest caterpillar I have ever seen.
We were walking along the streets of old San Juan in Puerto Rico when we came across a small park. I noticed the Plumeria were looking rather ragged, so I took a closer look only to find not one, but many, of these caterpillars ranging in size.
The biggest one we saw was almost as long as my hand. Yikes! He and his friends were munching on some frangipani (Plumeria spp.) leaves. One large adult caterpillar can eat three big leaves a day.
The frangipani hornworm moth is native to tropical and subtropical Americas and has been found as far north as the northeastern U.S.
Because it feeds on the toxic Plumeria plants, it has a bad taste and is toxic to predators. I’m really glad I paid attention to its coloration (bright red and orange is always a warning) and did not touch it – just to be safe.
According to University of Florida’s Entomology Department, the tetrio sphinx caterpillar can get as long as six inches. That’s about the size of the biggest one I saw in Puerto Rico.
It bites (yikes!) and it also has tiny hairs on it that can cause skin irritation. No thank you!