I love a good mystery

Yesterday we had a visit from a MOSI neighbor named Eric and his son Ethan. Along with Eric and Ethan came a curious green caterpillar with a spiked back end and a lateral row of eyespots on each side.

Jill and I ducked down to the office and hauled out the caterpillar reference books and websites. The problem with searching through moth caterpillars for a match is that moth caterpillars are incredibly variable. Many species have more than one color form and a single caterpillar can change color and markings by molting its skin. There are lots of great websites and books for researching caterpillars, but there are just so many possibilities that searching can be a challenge.

To start the search, we begin with what we know about physical characteristics. The spiked back end of the caterpillar narrowed us down to searching through Sphinx Moths. We then used color, shape and markings to help us narrow down the possibilities. The caterpillar was not brought to us with a host plant so we couldn’t use that to help narrow down the search.

We narrowed or search down to just one species- the Tersa Sphinx moth (Xylophanes tersa tersa).

Their larvae have either a green or brown form dotted with eyespots and terminate with a single spiked protrusion. They can consume many types of plants including pentas and Firebush (Hamelia patens) which are both common butterfly garden plants in Florida. The larva bury themselves in leaf litter or loose soil and mulch to form their pupa which will eventually wiggle back to the surface for the adult moth can emerge after metamorphosis.

The adult Tersa Sphinx moth (Xylophanes tersa tersa) looks to have been carved from wood. Tersa Sphinx moths can be found from Florida north to Massachusetts and have a wingspan around 3 inches. Adults can be seen flying right at dusk and searching for nectar plants, especially honeysuckle. Due to their large size and hovering form of flying that are often mistaken for hummingbirds at a distance.

What’s in a Name?: If you break down its scientific name: "xylo" is Greek for wood and "Phanes" was the golden winged being that hatched from the Cosmic Egg that was the source of the universe. In myth Phanes personifies light from chaos. Tersa comes to us from the Latin and means dry or parched, perhaps in reference to the brown coloring of this species.

If you want to search out your own mystery caterpillar identities, try the Discover Life caterpillar identification guide.