Invasion of the Forest Tent Caterpillar

Let’s travel along Memory Lane for this outdoor blog.  Back to the turn of the century, around 1999 and 2000.  The years we Upper Peninsula residents learned about the Forest Tent Caterpillar.  Many of us don’t want to look backward to be reminded of these creatures, but let’s reminisce briefly for those who have never weathered such an invasion.

What triggered this memory was this eastern tent caterpillar nest near the Bishop Baraga Shrine last Friday:

Eastern tent caterpillar nest

Almost rather pretty shimmering in the sunshine, right?  These are the more common variety of tentworm caterpillars.  They’re fond of wild cherries, or ornamental trees such as crab-apple, apple, plum, peach and cherry.  We co-exist rather happily with these caterpillars.  Hardly even know they’re around…

However, back in 1999, rumors whispered from the south.  The forest tent caterpillars were marching north from Wisconsin.  Entire swaths of trees were denuded of leaves as the caterpillars moved toward Lake Superior.  A driver along an interstate might suddenly notice bare tree limbs, completely devoid of greenery, with dozens or hundreds of acres of trees suddenly decimated by the army of multi-legged leaf-munchers.

We didn’t think too much about it until the army arrived here.  Until our tree leaves were consumed.  Until we were desperately thinking of creative ways to save some of our trees, especially prized oaks.  First we boiled up gallons of the hottest cayenne pepper-laced water. That didn’t even burn their feet. We finally settled upon a necklace of aluminium foil drenched with cooking oil near the tree base. 

The hungry fellows like wild cherry trees like their cousins, but they especially enjoy supping on poplars and oaks. Apparently their invasions occur in cycles of ten to twenty years. 

They settled thick upon the land for two years.  There were coccoons in the eaves, the awnings, the trees, the bricks, the blocks, the windows, the doors.  Everywhere the forest tent caterpillars could imagine.  We have a–shall we say, fond?–or at least, amusing?– memory of our son’s graduation party in 2000.  We set up folding tables on the side lawn, beneath the oak.  Can you perhaps imagine the scene as hundreds of tentworms dropped out of the tree onto the tables, perhaps frightening away guests?  My mother-in-law just mentioned that she kept herself busy inside of the house, hoping perhaps to avoid the industrious caterpillars.

Another memory:  in their march through L’Anse, they were so thick they covered the gas pumps at a local station.  Can you imagine the thrill of pumping gas through that quagmire?

Nine years later remnants of the nests remain.  I did an extensive search to photograph one of the beautiful carcasses for you.  At least two presented themselves.  For your viewing pleasure:

Exhibit A. Old forest tent caterpillar cocoon

One of my most miserable outdoor memories occurred in the midst of this invasion.  It was spring.  I wandered into the woods, about a half mile up the road from our house.  Probably thinking of morels or spring wildflowers or the challenges of the day, I didn’t notice until too late. 

Suddenly, unexpectedly, I was surrounded by strands of webs.  Hundreds, thousands!  Everywhere one turned, the sticky webs covered glasses, hair, eyes, clothes.  You couldn’t breathe without ingesting them.  It felt like a thousand almost-invisible ropes were surrounding you, tying you up, immobilizing you.  I tried to run but became more deeply entangled in webs.  Couldn’t even see because my glasses were covered by the threads.  The vague memory of the horror movie “The Birds” surfaced and I felt like screaming.  Honestly, it was not pleasant.  I didn’t return to the woods for at least a month after that adventure…

Here is another specimen left over from those days:

Exhibit B. So glad I didn't wash that shed window for ten years!

We’re truly hoping they don’t return to the Upper Peninsula for a long, long time.  Once every lifetime is probably enough…

P.S.  Besides photographing old caterpillar nests today, I drank jasmine tea outside in the cold 45 degree wind talking with my mother-in-law on the phone.  How’s that for an outdoor adventure?  It counts, doesn’t it?