Boise State University

Bats, a friend of Idaho farmers, draw Boise State biologist’s interest

Boise State biologist Jesse Barber with a big brown bat, Eptesicus fuscus.
Boise State biologist Jesse Barber with a big brown bat, Eptesicus fuscus. Boise State University

Idaho’s skies are host to an impressive variety of things that fly, from raptors to songbirds. Boise State University is well-known for its Raptor Research Center and Intermountain Bird Observatory programs that study these fascinating creatures. These programs, combined with work from our sister institutions across the state, are giving us a better understanding of the health and complexity of our ecosystem.

But many people don’t realize that Idaho also is home to 14 species of bats, including Townsend’s big-eared bats, little brown bats and big brown bats. Southern Idaho potato and onion farmers have barns full of bats, and they translate to a quantifiable economic gain.

That’s largely because bats love bugs, and they are voracious eaters. Studies have shown that they can eat as many as 1,200 insects in an hour. And they’re found on every continent except Antarctica, meaning they’re helping balance the population of problem insects around the world.

Regionally, the recent confirmation of white-nose syndrome, a disease of hibernating bats, in Washington state has heightened concern over the possibility of WNS in Idaho. Rita Dixon, state wildlife action plan coordinator for the Idaho Department of Fish and Game, is part of a team working to prevent the introduction of the fungus while preparing for its potential arrival. This includes development of an interagency coordinated response plan.

In addition to swabbing samples from bats and caves, the department is working with key partners to contribute to the North American Bat Monitoring Program, which will provide important information on the distribution and abundance of bats.

It’s estimated that bats contribute pest control worth more than $313 million to the agricultural industry every year. Worldwide, a study by Justin Boyles at the University of Pretoria determined that bats add at least $3.7 billion in value per year, including the reduced cost of pesticide application. And that doesn’t take into account the “downstream” impact of pesticide contamination.

Bat studies have led to advancements in sonar, vaccine development and blood coagulation, among other things. But despite their obvious value, bats get a bad rap. They’re often seen as scary and maligned for being a major source of rabies.

Boise State biologist Jesse Barber points out that there is less than 1 percent prevalence of rabies in bats, lower than in most other species. But with such a large number of bats in the air, and with most testing done on sick bats found on the ground, public perception is skewed.

Barber is an expert on bats. He has studied them for years around the world, including in South America and Africa, as well as here in Idaho. An evolutionary biologist, he is most interested in how life has evolved.

Bats and moths have long been locked in a co-evolutionary battle of predator and prey. Seeing how each species has adapted to evolutionary changes in foes is helping Barber unlock this mystery.

Many moths are equipped with bat-detecting “ears” — an area on the moth’s abdomen that vibrates in response to bat sonar, allowing moths to evade a bat attack. In the field and in his lab, sometimes referred to as the Bat Cave, Barber studies how moths warn bats that they taste bad by using their own ultrasonic reply to bat sonar. Other moths bluff that they taste bad (by using acoustic mimicry) and in some cases successfully jam a bat’s sonar.

One fascinating Barber study looks at how lunar moths use long hind-wing tail extensions as acoustic decoys to escape bat attacks. Spinning “tails” that extend off the hind wing draw the bat in. When the bat bites the narrow tail, it often cannot hold on or the tail breaks away, allowing the moth to escape.

Other studies focus on how sensory environments are shaping bat populations, particularly human-caused noise such as automobile traffic and compressor stations attached to natural gas extraction sites. Gleaning bats, those that eat bugs on the ground, find it particularly hard to hunt when surrounded by too much human-caused noise.

A study recently funded by the National Science Foundation will look at how noises from the natural environment also affect animal behaviors, including bats. Barber and his colleagues will set up a “phantom” river by re-creating whitewater noise to see how that affects bats and the insects they depend on.

Bats are just one example of the diversity of life on Earth, a diversity that’s disappearing at an alarming rate. Thanks to the efforts of Barber and other evolutionary scientists, bats are helping to increase our understanding of the natural world.

Mark Rudin is vice president for research and economic development at Boise State University. His monthly column looks at the state of scientific discovery and economic development in Idaho and beyond.