How venomous caterpillars could help humans design life-saving drugs

Some species of caterpillar come armed with powerful venoms. Harnessing them could help us design new drugs.

When you think of venomous animals, caterpillars probably aren’t the first thing that comes to mind. Snakes, of course. Scorpions and spiders, too. But caterpillars?
Yes, indeed. The world turns out to be home to hundreds – perhaps thousands – of species of venomous caterpillars, and at least a few of them pack a punch toxic enough to kill or permanently injure a person. That alone is reason for scientists to study them. But caterpillars also contain a potential windfall of medically useful compounds within their toxic secretions.
“Will we get to the stage where we’ll be taking things from their venoms that are useful? Definitely,” says Andrew Walker, an evolutionary biologist and biochemist at the University of Queensland, Australia. “But there’s a lot of foundational work to do first.”
Caterpillars are the larval stages of the insect order Lepidoptera, the butterflies and moths. It’s just one of many animal groups with little-known venomous members. (Venoms are toxins that are deliberately injected into another animal, while poisons sit passively in an organism’s body, waiting to sicken a potential predator.) By biologists’ best estimate, venoms have evolved at least 100 times across the animal kingdom.
Many venoms are complex, some containing more than 100 different compounds. And they’re also strikingly diverse. “No two species have the same venom arsenal,” says Mandë Holford, a venom scientist at Hunter College and the American Museum of Natural History in New York City. “That’s why it’s important to study as many species as we can find.”