Web Worms I’ve Known and Loved

OK, I know this one is weird, even for me, but I do love these guys, except when they are eating the leaves on my trees.

Although we now spend 5 or 6 months in Yellowstone every year we live, or at least have a house in Southeast Texas. When many people think of Texas they think of the drier parts but we live in one of the wetter parts with huge loblolly pines, magnolia trees, oaks, sweetgums, swamps, and alligators.

For years we have had a problem with web worms (some people call them army worms or tent worms) that build webs in our sweetgum trees and eat almost every leaf. They are the caterpillar stage of a moth and all they do is eat. I don’t use traditional pesticides so for a number of years we just sat and watched the web worms do their damage. But then I heard about parasitic wasps. There are many, many species of wasps in this world. Most of us only notice the ones that sting us. But there are thousands of species of parasitic wasps, many of which are beneficial to humans. Parasitic wasps pollinate fig flowers and thus make figs (Queen of Trees is about figs and their wasps and is one of the most beautiful movies ever made) possible and they lay their eggs in the eggs or caterpillars of many insects that damage our crops and trees.
I bought a bunch of wasps from a beneficial insect company. The wasps lay their eggs in web worms. When the eggs hatch the larva feed on the web worms. Our sweetgums are really tall and the wasps were really tiny so I got a ladder, put it on the second floor balcony of our house, climbed it and released the wasps. Do you remember the scene in “The Wizard of Oz” when the Wicked Witch of the West has told her monkeys to go get Dorothy and she is standing at her window yelling “Fly! Fly!” Well that’s how I felt. I was suddenly the Wicked Witch of the West, so I yelled “Fly! Fly!” figuring those little guys could use all of the help they could get. I didn’t notice any improvement in the web worm situation that year, but the next year and several years following we had much lower populations of web worms. One trial isn’t proof they worked but I prefer to think they did.

Another thing we have in East Texas is barred owls. My husband has become quite an expert at calling them. They either reply or fly closer to him, or both. One evening I had talked him into calling up a barred owl. We were standing on the front porch and he called several times. During the second or third call I noticed a bunch of web worms were flipping the front end of their bodies around very quickly. My husband went to the web worms and hooted at them. They started flipping around again! Why? We pondered on that for days. Then my husband had an idea. He wouldn’t tell me what it was until he did some reading. He discovered that the frequency he was hooting at is the same frequency that paper wasps emit when they are beating their wings. The web worms use the hairs on their bodies to detect the wasps and were trying to evade them! The poor web worms have to worry about two types of wasps, the tiny ones I’ve already mentioned and paper wasps that tear web worms apart and feed them to their babies.

A Barred Owl on Our Land
A Barred Owl on Our Land

Pretty neat, but what does all of this have to do with Yellowstone? Recently some friends told us about Joffe Lake. It is a smallish lake below Africa Lake just south of Mammoth. We went there and found a female sharp-tailed grouse and some web worms on some choke cherry bushes.

Yellowstone Web Worms
Yellowstone Web Worms

As an experiment we really thought would not work he hooted at the web worms and guess what!? They react the same as our East Texas web worms! They were flipping all over the place! So they can evade paper wasps too.

Yellowstone Web Worms
Yellowstone Web Worms

Now you are wondering how you could have lived so long without knowing this and thinking your life is now complete. Right??

Yellowstone Web Worms
Yellowstone Web Worms

8 thoughts on “Web Worms I’ve Known and Loved

    1. You set the bar (bear) to high and you don’t see the little stuff. I hope you are with us sometime when there are web worms around. Watching Verne hoot at them, and seeing their response, is really entertaining, or maybe I am just easily entertained. He’s been doing it for at least 20 years and I still love it.

    1. Thanks Barbara. I didn’t think about it until I read your comment but when we were little my grandmother took us to see a play of The Wizard of Oz in Fort Worth. It was in a theatre in the round so all of the characters had to enter the stage by going down an aisle. The ORIGINAL Wicked Witch of the West from the Movie was in that play. She ran down the aisle where I had an edge seat. She ran right past me in all her greenness. Scared me to death!! Couldn’t sleep without my stuffed rabbit for weeks.

  1. Thanks for this info, Judy, very interesting. This year, we have those pesky web worms in our river birch trees for the first time ever. I will have to look in to the parasitic wasps as we don’t like using pesticides either, but I do like my river birch trees.

Leave a Reply