Tobacco hornworm in hand while eating a tomato plant (photo from Wikimedia)

5 August 2026

This very large green caterpillar is a tobacco hornworm (Manduca sexta). Though its name suggests it feeds only on tobacco, its hosts include many plants in the Solanaceae family including tobacco, tomatoes, Datura (ex: jimsonweed), bell peppers.

Tobacco hornworm on a tomato plant (photo from Wikimedia)

From hatch to full-grown, the caterpillar feeds for two to three weeks before it begins to wander, looking for a place to pupate underground in loose soil. 7 to 10 days later it emerges as a large moth, the Carolina Sphinx moth also called the tobacco hawk moth.

(video embedded from entomology_1 on YouTube)

The Carolina sphinx moth is famous for its ability to hover like a hummingbird as it drinks from deep flowers. Here it is in slow motion in a wind tunnel.

When it’s time to lay eggs this moth must find a host plant that doesn’t smell sweet. How do they find it?

Carolina Sphinx moth, female, a.k.a. Tobacco hawk moth (photo from Wikimedia)

In a recent study, researchers examined the tiny hairs on the wings of Carolina sphinx moths (tobacco hawk moths) and found they have a sense of smell!

Looking at tiny wing hairs with both light and scanning electron microscopy, [researchers] found the hairs were porous: a telltale sign of olfactory function. …

The team placed the delicate detached wings between two electrodes and wafted odor molecules representing various chemical classes over them, hoping for a response. They reacted to … two amines—a group of smelly organic compounds derived from ammonia)—called pyrrolidine and piperidine … found in pungent, rotting smells, but also in the olfactory bouquet of tobacco plants..

These same compounds are part of the “smell” of tomato plants and probably other members of Solanaceae.

So when a Carolina sphinx moth flies past your tomato plants, its wings smell a place to lay eggs.

Read more at the Journal of Experimental Biology: Tobacco hawkmoth wings have a sense of smell. Watch a tobacco hornworm develop from egg to adult in this 6-minute video: Manduca sexta, from egg to adult on YouTube.