Bat deaths over the last two decades have cost American taxpayers in lost crops, higher taxes, and pricier bonds

How much is a bat worth? Protecting these tiny insect‑eaters isn’t just good for farms – their deaths cost taxpayers and the wider economy

A healthy bat hangs in a cave, resting up to eat its weight in bugs at dusk. Liz Hamrick/TVA

Dale Manning, University of Tennessee; Anya Nakhmurina, Yale University, and Eli Fenichel, Yale University

Most Americans tend to think about bats only around Halloween, but the U.S. economy benefits from these furry flying mammals every day.

Bats pollinate plants, including many important food crops, when they stop by flowers to drink nectar. Their guano is mined from caves for fertilizer. And they eat a lot of bugs – the kinds that bother people (think mosquitoes) and others that destroy crops that humans depend on for food.

Sadly, bat populations are declining rapidly in North America. A driving force is a fungal disease known as white-nose syndrome, which has spread among bats throughout the United States. When a bat population crashes, fewer bats are around to eat bothersome insects. All those additional insects can do serious damage.

So, when bats disappear, farms become less productive, and that has broad implications for the agricultural economy, human health, rural governments and even financial markets.

Bats love to eat the bugs that bother people

First, consider how many insects bats eat.

A reproductive female big brown bat can eat its body weight in insects every night in the summer, precisely when farmers are growing food.

Mexican free-tailed bats head out of Bracken Bat Cave, near San Antonio, Texas, for an evening of feasting on insects. In summer, the cave is home to the largest bat colony in the world. Ann Froschauer/U.S. Fish and Wildlife Service

One of those insects is the cucumber beetle, which matures from rootworm – a scourge of U.S. cornfields. Rootworm destroys more than 340 million bushels of corn across the U.S. Midwest and South each year, even as farmers spend US$1 billion annually on pesticides to control outbreaks.

A colony of 150 big brown bats can consume 600,000 cucumber beetles in a single year. If each female cucumber beetle – assuming half are female – had 110 rootworm larvae, the typical brown bat colony would prevent the production of 33 million rootworms.

Farmers experience economic damage when rootworm concentrations exceed about 0.5 per corn plant. Typical planting densities exceed 30,000 corn plants per acre in the Midwest. Therefore, the rootworms that would have hatched could damage more than 2,000 acres of corn – if bats weren’t around to eat the cucumber beetles first.

That is a significant amount of pest control provided by bats!

The disaster known as white-nose syndrome

In the winter of 2006, the fungus that causes white-nose syndrome, the aptly named Pseudogymnoascus destructans, was first detected in the U.S. near Albany, New York.

From there, it spread across the country, infecting 12 species of bats, three of which are listed as endangered under the Endangered Species Act. A 2010 study found white-nose syndrome had killed between 30% and 99% of the bats in infected colonies.

A little brown bat with the telltale signs of white-nose syndrome, a fungal infection that saps the bats’ energy. Ryan von Linden/New York Department of Environmental Conservation

As of March 2026, the fungus causing white-nose syndrome had been detected in 47 states, reaching as far west as California, Washington and Oregon. White-nose syndrome spreads primarily through bat-to-bat contact, though humans also contribute to the spread when cave explorers carry the fungus from one cave to another.

Despite coordinated efforts by state and federal wildlife agencies to limit access to caves where bats live and slow the transmission, white-nose syndrome continues to spread rapidly. When bats get infected, they wake up early from hibernation and use more energy over the winter. This depletes their fat reserves and causes them to die of starvation, leading to plummeting populations.

Bats’ role in food production

After white-nose syndrome arrives in an area, the loss of bats has significant consequences for farmers.

Yields fall as pests consume crops. To protect their crops, farmers purchase more chemical pesticides, so their costs rise as yields decline. The estimated agricultural losses from white-nose syndrome exceeded $420 million per year as of 2017.

A lesser long-nosed bat (Leptonycteris curasoae) feeding on an agave blossom in Arizona, spreading the flower’s pollen in the process. Rolf Nussbaumer/imageBROKER

Greater pesticide use is also associated with human health problems that can be avoided if bat populations remain healthy.

Losing bats hurts local governments financially

The story does not stop at the farm.

Counties in all U.S. states tax agricultural land based on its “use value” – in other words, based on how profitable the land is in agriculture. Without healthy bat populations, lower profits shrink the tax base, leaving cou