Complexity Matters » A Million Bats Died and 694 Tons of Insects Lived

A Million Bats Died and 694 Tons of Insects Lived

An emerging contagious disease called White Nose Syndrome (WNS) is killing hundreds of thousands of bats a year in the Northeastern United States, and scientists worry that some species could become extinct in coming decades.

Bats with the frothy looking white material on their noses, skin and wing membranes were first photographed in a New York state cave in 2006, and biologists began to study the fungal disease in 2007. Scientists estimate it has killed a million bats in 10 states, with potentially severe ecological and economic consequences. In most species, female bats produce only one baby a year, population losses do not quickly recover.

Thomas Kunz is Director of the Center for Ecology and Conservation Biology at Boston University. DeeAnn Reeder is an assistant biology professor at Bucknell University who specializes in comparative behavior and physiology of mammals. They discussed Bats in Peril on Radio Times, broadcast by National Public Radio.

The two professors say bats are a keystone species, meaning that they have a disproportionate impact on their environment and their absence would have dramatic ecological impact. They are the only mammals that actually fly, so they are unlike any other creatures. One out of every five mammals is a bat, and their diets and habits are diverse. Seventy percent of bat species feed on insects that feed on agricultural crops and forests. Professor Kunz explains those missing million bats would have eaten 694 tons of insects. They also eat plant pathogens. Some species eat fruit, frogs and fish, and only three percent of bats feed on blood.

The fungal disease is believed to have started in upstate New York and has now spread as far south as Tennessee. It appears to spread from bat to bat, sometimes killing up to 90 percent of a hibernating bat colony. When bats and other creatures hibernate in winter months their body temperatures drop and they tend to suppress their immune systems. In 2008 researchers discovered WNS was caused by an unusual Geomyces fungi, that likes cold and has been found in Antarctica. It’s not clear that the fungus is killing the bats. Professor Reeder explains the growth on their skin may be an irritant that wakes them inappropriately during hibernation, burning their stored body fat and inducing them into winter flights in search of food, and ultimately leading to their starvation.

“Bats have gotten bad press,” Kunz observes. In Western culture, we tend to fear things that come out at night, In Chinese culture, bats are considered good luck. Professors Reeder and Kunz say citizen scientists can help improve understanding of bats and WNS by reporting discoveries of sick or dying bats, or disoriented bats flying in daylight. The US Geological Survey has an excellent web page on WNS and bats. The US Fish and Wildlife Service tells how you can help.