Aug 03, 2017 I Paul Seaburn

Zombie Caterpillars Climb to Tops of Trees and Explode

Let’s get this out of the way right up front: Exploding Zombie Caterpillars would be an awesome name for a band.

However, you don’t want zombie caterpillar goo dripping down on you from trees and that’s what’s happening all over Britain as the fuzzy butterfly wannabes are never making it to the cocoon because a rare virus is eating away their brains and driving them to the tops of trees into the direct sunlight where they explode and spread the virus, starting the deadly cycle all over again. Can anything stop them? Is this a good movie plot?

Dr Chris Miller, mosslands manager for the Wildlife Trust in Lancashire, Manchester and North Merseyside, thinks so.

"It's like a zombie horror film.”

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Oak Eggar moth caterpillar

Dr. Miller is concerned particularly about Oak Eggar moth caterpillars, which are common in the UK and Europe. They eat heather and bilberry and generally stay hidden under the leaf cover. That’s why Dr. Miler was horrified on a recent walk in the woods in Lancashire.

"I was carrying out a large heath butterfly survey on Winmarleigh Moss and noticed a caterpillar hanging from the end of a branch of a small bush. Later on I saw another one hanging from a tall blade of grass - both were dead but otherwise intact. While checking some other branches I noticed small scraps of caterpillar skin on a couple of branches suggesting the two I had seen were not the only ones to be affected."

Normal and exploded Oak Eggar moth caterpillars

Miller didn’t find 4,000 dead caterpillars in Blackburn, Lancashire, but he found enough to be concerned. The dead bugs had been infected by the rare but well-known baculovirus which enters the caterpillars when they eat leaves covered with it. How do the leaves get covered? Send the kids out of the room for this part.

The virus changes the behavior of the normally darkness-seeking, bird-hiding caterpillars – making them crawl out into the open and high into the trees where, if they’re not eaten by birds, they’re cooked by the sun until they explode, sending virus-laden goo everywhere for the next generation to eat and be zombie-fied. Dropping from caterpillar-eating birds can also spread the virus.

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Oak Eggar moth

OK, you can bring the kids back in for the good news. Dr. Miller says he’s never seen the virus before now and neither has his colleague who’s been working for the Wildlife Trust for 25 years. That’s most likely because the virus doesn’t spread very far before quickly dying out. There’s no cure or preventative measures so the researchers just ask the public to notify them of caterpillar goo so they can monitor it.

Exploding zombie caterpillars that just die off until next year isn’t really much of a problem nor a decent movie plot. Perhaps someone could catch one just before it explodes and let it turn into a zombie mothman that destroys porch lights. Hmm…

Paul Seaburn

Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.

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