In Praise of Fuzzy Caterpillars

By Anita Sanchez

The last time I strolled along a trail at the Arbore­tum, I spot­ted anoth­er fall wan­der­er — a small black-and-white fuzzy cater­pil­lar. Unlike me, he had a clear pur­pose in his trav­els — he was seek­ing a cozy place to spend the win­ter. Once he found a shel­tered spot — under a log, or in a crevice of bark — he would shed all those fuzzy hairs and use them to craft a snug cocoon. This lit­tle fel­low was a hick­o­ry tus­sock moth. These moths munch on hick­o­ry leaves and the leaves of oth­er plants, but don’t cause a lot of dam­age to trees.

I’ve always had a soft spot for cater­pil­lars, and when I was a kid, I would have picked him up and maybe put him on a stick and watched him crawl along, just for fun. Seems as though noth­ing could be more harm­less than a fuzzy cater­pil­lar. But I’ve been see­ing these lit­tle guys all over the media late­ly— on Face­book, on Twit­ter, and even on the evening news and in the local papers. And the cater­pil­lars are always described with words like lethal,” dan­ger­ous,” and ter­ri­fy­ing.” And the scari­est word of all: ven­omous.” Was I real­ly risk­ing death when I picked up a tus­sock moth cater­pil­lar in my youth? Are they real­ly a life-threat­en­ing menace? 

In a word, no. Tus­sock moth cater­pil­lars don’t bite or sting. They’re not ven­omous in the sense that a cobra or a scor­pi­on is, with fangs or stingers to inject dead­ly poi­sons into humans. The prob­lem is that some of the cater­pil­lar’s bris­tles are what are called urticat­ing hairs. Like the spines of a net­tle, these hairs can cause a rash on sen­si­tive peo­ple, but it’s usu­al­ly a pret­ty mild irri­ta­tion. The skin on the palm of your hand is fair­ly thick, so you’re unlike­ly to have any prob­lem from pick­ing up a cater­pil­lar. But if the cater­pil­lar brush­es against an area with sen­si­tive skin, like your stom­ach or your neck, an itchy reac­tion is more like­ly. So don’t cud­dle them against your cheek, don’t put the bris­tles in your eye. Don’t lick them. (Peo­ple have done these things.)

It’s not that they’re try­ing to irri­tate us. It’s the way the cater­pil­lar sur­vives. When a blue jay grabs a cater­pil­lar for lunch, the cater­pil­lar thrash­es back and forth, thrust­ing the urticat­ing hairs into the bird’s face. The blue jay quick­ly learns to avoid white, fuzzy food. Lat­er, when the cater­pil­lar pupates, it uses the urticat­ing hairs to make its own cocoon. The soft lar­va inside the cocoon is defense­less, but the cocoon would be an itchy mouth­ful for a hun­gry predator. 

So tus­sock moth cater­pil­lars are cer­tain­ly not lethal. The warn­ings about ven­omous” and poi­so­nous” are mis­lead­ing — pos­si­bly aller­genic” is a bet­ter term. They will not inject ven­om into you and kill you. 

The good thing about these lit­tle fel­lows is that they’re a native species. They’ve been here for mil­len­nia. They’re yet anoth­er strand in the immense and inter­twined food web of the east­ern for­est. In all their life stages — egg, lar­va, pupa, adult — there is some­thing that eats them, some­thing that needs them for nutri­tion. Many wood­land birds, like chick­adees and nuthatch­es, are espe­cial­ly fond of insect eggs. The tus­sock moths belong here. 

Know­ing all this, try to resist the temp­ta­tion to squish them or spray them. They grow up into harm­less but absolute­ly gor­geous moths. Think of the beau­ty we’d miss.


Fall 2018

Volume 36 , Number 4

Share this

The Latest from Landis

Aug 06, 2022

Landis Forest 5K - August 6, 2022

A record turnout! Click here to view all the great photos from this event, and... read more

Jun 10, 2022 | Anne Donnelly

Don't Overlook Your Reciprocal Admissions Privilege

A sometimes overlooked benefit of your Landis Arboretum membership is the American Horticultural Society Reciprocal... read more

May 29, 2022

Scenes From the Spring Plant Sale

Thanks to our many wonderful volunteers, plant consignors, vendors, and customers, the Landis Signature Spring... read more

May 28, 2022 | Fred Breglia, Executive Director

From the Director’s Desk: Q&A, Part III

In this last Q&A session, I am focusing on leaf color change during the... read more

May 28, 2022 | Erin McKenna Breglia, Landis Gardener

From the Garden: Milkweeds for Monarchs!

Many people enjoy seeing butterflies in our Landis gardens. especially the monarch butterfly, Danaus... read more

May 28, 2022 | Anita Sanchez

Life and Death on the Lawn

It’s a beautiful summer day. You’ve finished your stack of books from the Landis... read more

News Archive