Now scientists at Penn State University have found the single gene that enables the virus to carry out its dark deeds.
The caterpillars would normally return to the ground to hide after feeding on leaves, but the baculovirus reprogrammes them to stay in the trees, melts them, then drips down among the remains to infect more of the creatures.
Researcher Kelli Hoover, writing in Science, said: ‘When gypsy moth caterpillars are healthy and happy, they go up into the trees at night to feed on leaves, and then climb back down in the morning to hide from predators during the day.
‘When they are infected, as they get sicker they stay up in the trees and die up there.’
He added: ‘There are other genes in the virus that then make the caterpillar melt. So it becomes a pool of millions of virus particles that end up dropping onto the foliage below where it can infect other moths that eat those leaves.’
His team discovered that the gene responsible for controlling the caterpillar is called egt. Read More