Think of bats as nature's pesticide. One big brown bat, a species that lives in Connecticut, can eat roughly 9,000 insects in a year. Added together, bats' consumption of insects equals $22.9 billion in insect control for U.S. Agriculture, according to Connecticut's Department of Energy and Environmental Protection.
But an invasive fungus that causes a disease called white-nose syndrome has been threatening bats for years. In Connecticut, five bat species are listed as endangered: the little brown bat, northern long-eared bat, tri-colored bat, eastern small-footed bat, and the Indiana bat.
When farmers lose the free services of bats, they may have to turn to pesticides to control their pests. That can be costly for farmers and for the environment, said DEEP's Devaughn Fraser. "The more pesticides you use, the more out of balance the ecosystem gets," she said. "You need to put in more money into chemical uses to control insects."
White-nose Syndrome
Millions of hibernating bats have been wiped out by white-nose syndrome, which scientists believe has been in America since at least 2006.
Fraser says the Northeast got hit first before it began its spread across Canada and the U.S. Some species were hit harder than others. More than 90% of northern long-eared, little brown, and tri-colored bats in North America were killed within 10 years.
There is a glimmer of hope. Fraser said studies suggest that some bat species that have survived are showing signs of a natural resistance to the fungus. So the evolutionary process of natural selection is underway for certain species, like the little brown bat.
The Northeast is no longer seeing "drastic declines in the colonies, and in some cases, populations of at least some species are starting to make a very slow recovery," Fraser said.
But if a recovery is possible, it will take a long time. Bats don't reproduce quickly. One female bat has only one baby a year.
How you can help bats
One simple step is to turn off your outside lights at night. Fraser said some bats are averse to light, so if you keep a light on, it's "going to limit the number of species or the number of individual bats that are going to be able to use that that airspace for foraging."
Different bats have different foraging preferences. If you want to ensure an area offers a variety of insect options, grow a lot of different native plants to promote a high insect biomass.
Bat houses are another option, but you need the right place to hang one. Fraser advises hanging it on a building or a pole, but she said to avoid trees because that can give predators access to baby bats.
If you do hang a bat house, you'll need some patience. It can take a female bat several years to decide to make your shelter her home.
