Exploding Zombie Caterpillars Discovered in English Countryside Death March

zombie caterpillar
The caterpillars were discovered hanging high up in trees having burst open so the virus could infect others. Lancashire Wildlife Trust

Zombie caterpillars that explode out of their skins have been discovered in the English countryside.

The caterpillars were found by wildlife experts who found their remains at the top of trees—a highly unusual location for the species involved, which normally lives in the undergrowth, hidden away from predators.

"It's like a zombie horror film," Chris Miller, manager of the Wildlife Trust for Lancashire, U.K, said in a statement. "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."

The caterpillars belong to the oak eggar moth species, which is native to Europe and the British Isles. The Wildlife Trust is currently transferring butterfly populations from Winmarleigh Moss, a nature reserve, to other parts of the country where certain species are extinct.

While carrying out this work, Miller and colleagues came across a multitude of dead caterpillars hanging from high up tree branches, with their skin torn apart.

"Whilst checking some other branches I noticed small scraps of caterpillar skin on a couple of branches suggesting the two I had seen where not the only ones to be affected. It's pretty gruesome when you think about it," Miller said.

"It is really unusual seeing caterpillars high up as they can be eaten by birds. This is a caterpillar of the oak eggar moth which eats heather and bilberry so it is normally hidden in the undergrowth, not at the top of plants."

An oak eggar moth, the species of caterpillar affected by the baculovirus. Lancashire Wildlife Trust

The caterpillars had been attacked by a type of baculovirus—a family of pathogens that infect invertebrates, most often larval moth species. The baculovirus normally infects a host creature when it feeds on plants contaminated with the virus. This dissolves into the stomach, from which the virus gains access to the host's body.

The virus causes the host insect to feed without resting and climb up to higher parts of tress where it eventually dissolves, allowing the virus to burst out onto leaves below, where it can infect other hosts. It is thought the baculovirus changes the way the host responds to light, encouraging them to climb up to their deaths.

The Wildlife Trust is now asking people to look out for caterpillars and snails high up on leaves and report it to them if they do.