Found on Everglades tomato, these caterpillars are the larva of the Carolina Sphinx moth. Noticed especially around late afternoon into dusk, these large moths are often mistaken for hummingbirds due to both their size and hovering style of flight. These caterpillars can grow to nearly four inches in length and can decimate tomato plants, consuming foliage and fruit at a startling pace. Their excellent camouflage makes them very hard to see, and during the day these caterpillars move to the undersides of leaves to avoid the sun and predators alike. Because they are hard to spot, most gardeners don't even realize there are hornworms in the garden until suddenly it seems as if their whole garden has been decimated.
The Tobacco Hornworm (Manduca sexta) does not just eat tobacco, as the name implies. These caterpillars are actually the more common of two species often found on tomato, pepper and potato plants. The Tobacco Hornworm and Tomato Hornworm are two of the most dreaded insects to most every home gardener and often spell the end to that perfect tomato for which you have been patiently waiting.
The caterpillars of Manduca sexta are used often in scientific research, as they are easy to grow in a laboratory setting, have a short life cycle and have a nervous system that is easily accessible. Some recent research even shows that as adults, these moths can slow their brains down so they can best absorb light in dim settings, even as the moth is flying, hovering and feeding on flowers. Check out the Science Daily article : "How the hawkmoth sees, hovers and tracks flowers in the dark" for even more information. When these caterpillars feed on tobacco leaves they are able to absorb the nicotine from the plant and metabolize the toxicity of the nicotine. The nicotine remaining in their system makes them distasteful to predators, but also is breathed out through the caterpillar's respiratory system and into the air. This toxic "bad breath" helps deter spiders from getting too close and serves as another defense mechanism for the hornworm.