NEBRASKAland Magazine is dedicated to outstanding photography and informative writing with an engaging mix of articles and photos highlighting Nebraska’s outdoor activities, parklands, wildlife, history and people.
Issue link: http://mag.outdoornebraska.gov/i/708333
58 NEBRASKAland • AUGUST-SEPTEMBER 2016 places much warmer than their winter hangouts, especially females. They find their way into attics, hang among the leaves of trees, or crawl into the cracks of cliffs or under tree bark. Some have night roosts in trees or cliffs, where they take breaks between nighttime feeding sessions. Their appetite for night-flying insects is ravenous, and that alone is their primary value to the ecosystem in temperate climates such as ours. Bats eat everything from large moths and beetles to tiny mosquitoes and gnats, with some species showing at least a seasonal preference for certain types of insects. They are capable of consuming 40 to 100 percent of their body weight in a single night of feeding, which might amount to thousands of mosquitoes or more than one hundred moths. A single colony of 150 big brown bats in Indiana was estimated to eat nearly 1.3 million insects each year. The one million little brown bats lost to white-nose syndrome in the northeast would have consumed 700 to 1,450 tons of insects annually. Some of the insects bats consume, including flying moths and beetles that are the adult forms of crop pests such as the European corn borer, the western bean cutworm and three species of corn rootworm, can cause substantial losses in crop fields. A recent study estimated the insect control provided by bats to be worth more than $3.7 billion per year, and possibly as much as $53 billion, to agriculture in North America. This estimate was based on the increased yields farmers could attain, and the reduced costs of pesticides that would have to be applied if bats were not present, and even reducing the fungal diseases that are spread by insects. The benefits of insect control by bats may have a public health benefit as well. West Nile virus, first detected in the U.S. in 1999, has sickened tens of thousands of people and killed more than 1,800 in the United States, including 67 in Nebraska. Now the Zika virus, which can cause defects to infants born by women infected during pregnancy, is spreading around the globe. Both are spread by mosquitoes, which are consumed en masse by bats. White-nose Syndrome In the winter of 2005-2006, bat biologists were called into action when people began finding dead and dying hibernating bats in a cave in New York with a white fuzz on their nose and other parts of their bodies. The following winter it was found in four more caves. The culprit was soon identified as a fungus and the disease took on the name of the outward signs of infection: white-nose syndrome. Since then, white-nose syndrome has spread rapidly throughout the eastern United States and Canada. The fungus that causes it was first detected in Nebraska in 2015. And this year, it made a quantum leap to the state of Washington, the 29th state in which it was documented. The disease invades and ingests the skin of hibernating bats and causes them to wake more frequently during the winter, sometimes flying outside their hibernaculum or clustering near the opening, all of which depletes the fat reserves needed to survive winter. To date, the death toll is estimated at more than 6 million bats. In some caves, the floors were literally carpeted with carcasses, and losses ranged from 70 to 100 percent. In New York state, the disease reduced the population of little brown bats by an estimated 90 percent. Throughout the northeast, the northern long-eared bat declined by up to 99 percent. The latter led the U.S. Fish and Wildlife Service to list the northern long-eared bat as a threatened species. The agency chose not to designate roost trees or hibernacula, the places in which they hibernate, as critical habitat for the species, a move that would have required special management considerations. Threats to those habitats were not the problem, the agency determined. It was the fungus that causes the disease. The fungus thrives in the cool moist conditions present in caves and persists in the soil. It is believed to have hitchhiked here on the clothes or shoes of people who visited caves or mines in Europe or Asia, where native bats have become resistant to it. Man likely helped it make the jump over the Rocky Mountains or across the Pacific to Washington as well. Bats have taken care of the rest, spreading A western small-footed myotis huddles in the bark of a cottonwood tree in the Pine Ridge.