Bats: A Friend to Farmers . . . but in Big Trouble

April 6th, 2011 | Simcha Weinstein | Comments Off on Bats: A Friend to Farmers . . . but in Big Trouble

Most people aren’t really very fond of bats. It’s more likely that we even find the mammal a little spooky. It turns out however, that bats are a true friend of the agricultual community, saving the industry about 3 billion dollars each year by gobbling up insects that eat or damage our crops.

A single little brown bat, which has a body no bigger than an adult human thumb, can eat 4 to 8 grams (the weight of about a grape or two) of insects each night. Although this may not sound like much, it adds up–the loss of one million bats in the Northeast has probably resulted in between 660 and 1,320 metric tons of insects no longer being eaten each year by bats in the region. And why the loss of bats?

For several years now, scientists have been sounding alarms about a devastating fungus, White-Nose Syndrome (WNS), that has literally decimated bat populations in the Northeastern U.S. Earlier this year, a survey of the bat population in New Jersey estimated that 90% of that state’s bats had been killed off.

“The disease is absolutely devastating, it’s unprecedented,” says Mylea Bayless, a biologist with Austin, Texas-based Bat Conservation International. “It’s causing population declines in wildlife that we haven’t seen since the passenger pigeon.” Bayless notes that bats have slow reproductive rates, usually giving birth to just one pup a year. So bat populations, she says, are going to be very slow to recover, “if they ever do recover.” The disease, adds Bayless, “is moving at a pace that’s astonishing, about 450 miles per year. In four short years, it’s now closer to the Pacific Ocean than it is to its point of origination in Albany, N.Y.”

Bats are the primary predator of night-flying insects. That not only includes pests like mosquitoes but also insects like corn earworm moths and cotton bollworms. In their caterpillar forms, those insects can destroy crops. A 2006 study of several counties in South-Central Texas concluded that the local bat population had an annual value of over $740,000 a year as a pest control — or up to 29% of the value of the local cotton crop.

A bat eats 60% to 100% of its body-weight in insects every day. One colony of Mexican free-tailed bats in Colorado’s San Luis Valley, an important agricultural region, “pulls about 100 metric tons of insects out of the air in a year.” And having bats in agricultural areas tends to move insects out of those areas, creating less need for dangerous and expensive pesticides.

And like honey bee colonies — which have also been facing massive die-offs in recent years — some bats are important pollinators and seed-distributors. Bats are crucial to the reproduction of tropical fruits like mangos, papayas, figs and wild bananas. And in Arizona, bats are the primary pollinators for three large cactus species that support much of the region’s ecosystem.

Bats may not be the little creatures that give us a warm fuzzy feeling inside when we think of them, but they are a vital part of our ecosystem and play a critical role in our food supply, particularl when it comes to using less pesticides.