Bats: Providing free bug population control

Brian Maddy County extension agent

July 25, 2014

When John Smith arrived off the coast of Virginia, his ships from the south of England carried on board one of the most devastating invasive species to North America, the mosquito.

Mosquitoes are vectors of devastating illnesses such as yellow fever, malaria, West Nile and the newest threat, chikungunya. Fortunately the second largest order of mammals were waiting for them, the bats.

There are over 1,200 species of bats worldwide. They are divided into two groups, microbats and megabats. Microbats eat mostly insect and megabats eat fruit, nectar and pollen; 70 percent of bats are microbats.

Georgia is home to 16 bat species. Two of the species, the Grey Myotis and the Indiana Myotis, are endangered. Each bat consumes approximately one third of its body weight in insects each evening.

Researchers estimate that 1,000 bats can consume up to 4 tons of insects per year. That’s a lot of bugs.

Bats are the only mammals capable of true flight. Most bats are very gentle and shy creatures. Bats have very acute hearing and track their prey through the use of echolocation, a form of Doppler radar.

Because they don’t flap their wings as birds do, but rather they flap their spread out digits for flight, this along with their very thin wings provides greater amount of maneuverability than birds. Their very sharp teeth allow them to bite through the hardened armor of insects. Bats are very much a friend to farmers and those folks who enjoy the outdoors.

Bats hibernate in the winter and live in forest, wetland and cave habitats during the summer. Ideal summer roosts may also include attics, eaves, chimneys, hollow trees, loose bark, rock crevices and cliff faces. They are very particular about their winter roost and may travel up to 300 miles to a cave or abandoned building.

Some bats are solitary while others may live in colonies of over a million. Bats generally breed in the late fall and one or two pups are born in May or June. The females may form a maternity colony of up to several hundred individuals and remain together until the pups can fend for themselves. This is usually in August or September. Some species can live up to 30 years.

There is a fly in the ointment so to speak. Another very unwelcome species has come to our shores from Europe. A devastating fungus called White-Nose Syndrome (WNS) has been killing millions of bats in 25 states and five Canadian provinces.

These bats transmit this disease while overwintering in caves. It causes the bats to become restless and use up their body fat too early and they die of starvation. Eighty percent of the bats in those regions have perished since the winter of 2007-2008. It is now spreading to the southern states.

What does this mean? The little brown bat eats approximately 4 to 8 grams of insects each night. Multiply that by a million bats and that puts as much as 1,320 metric tons of insects