Natural pest-control services provided by insect-eating bats in the United States likely save the U.S. agricultural industry at least $3 billion a year, and yet insectivorous bats are among the most overlooked economically important, non-domesticated animals in North America, noted the study’s authors, scientists from the University of Pretoria (South Africa), the U.S. Geological Survey (USGS), the University of Tennessee, and Boston University.
"People often ask why we should care about bats,” said Paul Cryan, a USGS research scientist at the Fort Collins Science Center and one of the study’s authors. “This analysis suggests that bats are saving us big bucks by gobbling up insects that eat or damage our crops. It is obviously beneficial that insectivorous bats are patrolling the skies at night above our fields and forests—these bats deserve help."
The value of the pest-control services to agriculture provided by bats in the U.S. alone range from a low of $3.7 billion to a high of $53 billion a year, the authors estimated. They also warned that noticeable economic losses to North American agriculture could well occur in the next 4 to 5 years because of the double-whammy effect of bat losses due to the emerging disease white-nose syndrome and fatalities of certain migratory bats at wind-energy facilities. In the Northeast, however, where white-nose syndrome has killed more than one million bats in the past few years, the effects could be evident sooner.
“Bats eat tremendous quantities of flying pest insects, so the loss of bats is likely to have long-term effects on agricultural and ecological systems,” said Justin Boyles, a researcher with the University of Pretoria and the lead author of the study. “Consequently, not only is the conservation of bats important for the well-being of ecosystems, but it is also in the best interest of national and international economies.”
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, the authors note. 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.
“Additionally, because the agricultural value of bats in the Northeast is small compared with other parts of the country, such losses could be even more substantial in the extensive agricultural regions in the Midwest and the Great Plains, where wind-energy development is booming and the fungus responsible for white-nose syndrome was recently detected,” said Kunz.
Although these estimates include the costs of pesticide applications that are not needed because of the pest-control services bats provide, Boyles and his colleagues said they did not account for the detrimental effects of pesticides on ecosystems or the economic benefits of bats suppressing pest insects in forests, both of which may be considerable.
The loss of bats to white-nose syndrome has largely occurred during the past 4 years, after the disease first appeared in upstate New York. Since then, the fungus thought to cause white-nose syndrome has spread southward and westward and has now been found in 15 states and in eastern Canada. Bat declines in the Northeast, the most severely affected region in the U.S. thus far, have exceeded 70 percent. Populations of at least one species, the little brown bat, have declined so precipitously that scientists expect the species to disappear from the region within the next 20 years.
The losses of bats at wind-power facilities, however, pose a different kind of problem, according to the authors. Although several species of migratory tree-dwelling bats are particularly susceptible to wind turbines, continental-scale monitoring programs are not in place and reasons for the particular susceptibility of some bat species to turbines remain a mystery, Cryan said.
By one estimate, published by Kunz and colleagues in 2007, about 33,000 to 111,000 bats will die each year by 2020 just in the mountainous region of the Mid-Atlantic Highlands from direct collisions with wind turbines as well from lung damage caused by pressure changes bats experience when flying near moving turbine blades. In addition, surprisingly large numbers of bats are dying at wind-energy facilities in other regions of North America.
“We hope that our analysis gets people thinking more about the value of bats and why their conservation is important,” said Gary McCracken, a University of Tennessee professor and co-author of the analysis. “The bottom line is that the natural pest-control services provided by bats save farmers a lot of money.”
The authors conclude that solutions to reduce the impacts of white-nose syndrome and fatalities from wind turbines may be possible in the coming years, but that such work is most likely to be driven by public support that will require a wider awareness of the benefits of insectivorous bats.
The article, “Economic importance of bats in agriculture,” appears in the April 1 edition of Science. Authors are J.G. Boyles, P. Cryan, G. McCracken and T. Kunz.
Founded in 1839, Boston University is an internationally recognized institution of higher education and research. With more than 30,000 students, it is the fourth largest independent university in the United States. BU contains 17 colleges and schools along with a number of multi-disciplinary centers and institutes which are central to the school's research and teaching mission.Thomas Kunz
Thomas Kunz | Newswise Science News
Plasma-zapping process could yield trans fat-free soybean oil product
02.12.2016 | Purdue University
New findings about the deformed wing virus, a major factor in honey bee colony mortality
11.11.2016 | Veterinärmedizinische Universität Wien
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
05.12.2016 | Power and Electrical Engineering
05.12.2016 | Materials Sciences
05.12.2016 | Power and Electrical Engineering