This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
A Hickory Tussock Moth caterpillar (the black and white one) with a Banded Tussock Moth caterpillar above it.
Last week, my parents’ yard in Western Massachusetts was overrun with fuzzy black and white creatures known as Hickory Tussock Moth caterpillars (Lophocampa caryae). Just after a rainstorm, I noticed that the caterpillars were hanging from trees like spiders, lowering themselves from branches on lines of silk (see video below; apologies for the commentary in the background).
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
Everywhere I walked that day I saw caterpillars hanging from leaves like ornaments. Jeffrey Miller, a Lepidoptera expert at Oregon State University, explains that caterpillars use silk as a lifeline all the time, not just when spinning cocoons. “They spin silk from a gland built into their multiple mouthpart bits. They use silk as a place (pad) to molt, when they are disturbed by wind, when threatened by a predator, and when - those that must - lower themselves to the ground and look for a place to make their pupa,” he says.
Last year, my daughter and I collected two Tussock Moth caterpillars and watched them weave cocoons inside pickle jars. (Note: the hairs on these caterpillars are allergenic to some and may cause an itchy rash. We rarely touch our caterpillars directly and transfer them into and out of containers using small twigs or leaf stems). This year, with the dry weather keeping fungal diseases at bay, the caterpillar population has exploded, and my daughter caught a dozen, which we’re raising in five separate containers. That’s a lot of work! We feed them fresh leaves and clean out their frass (poop) every day. But it's fun and rewarding to watch them grow and eventually transform into moths.
For details on how to raise caterpillars, see my earlier posts here, here and here.