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 outb