A bug is being blamed for turning caterpillars into what has been called exploding zombies.
The recent outbreak in the UK was spotted by Doctor Chris Miller, a Wildlife Trust manager, when he was in the field conducting a butterfly survey.
He said he noticed a caterpillar hanging from a branch and another off a blade of grass, dead, but otherwise intact
Miller added: "Whilst 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.
"It's pretty gruesome when you think about it."
The likely culprit has been found to be a bug called a baculovirus, which basically overrides an insects own instincts to avoid sunlight and forces it to climb right into it and die.
After their insides are liquefied, their bodies explode and the virus remains ooze downwards and infect others.