In pictures: White Nose Syndrome

Scientists are baffled and concerned. They say the long-term effects of huge numbers dying could be devastating: bats are predators of forest and agricultural pests, and in some parts of the world are pollinators.

In the short-term, farmers and gardeners may notice a significant increase in the number of bugs this summer.

Bats eat about half their weight in insects every night, and a drop in the bat population likely means an increase in the bug population.