Bats, the only mammals that fly, often carry negative connotations based on myths instead of facts. Erin Gillam, assistant professor of biology, and a team of graduate students are conducting research on the role bats play in ecosystems around the globe and on their ability to communicate.
Gillam and her team have conducted field research on bats in Theodore Roosevelt National Park in the Badlands of North Dakota, in Texas and in Costa Rica. In her research, Gillam records bat calls through portable sensors and captures bats using mist nets. NDSU graduate students Paul Barnhart from Bismarck, N.D., Lucas Bicknell from Fargo, Karina Montero from Costa Rica and Derek Stonefish from Cannonball, N.D., are working with Gillam on research projects. One aspect of the research, funded by the North Dakota Game and Fish Department, includes a statewide survey of the bat population in North Dakota to determine where they’re foraging and roosting. Of concern is “white-nose syndrome,” a fungal disease that kills hibernating bats and is spreading in various areas in the U.S. The research team also is investigating the effect of wind energy on bats in North Dakota and the communication mechanisms of bats in Costa Rica.
Gillam and Barnhart presented initial results of their research at the North American Symposium on Bat Research in Denver Oct. 29 in a presentation titled “Distribution, abundance, and habitat use of bats in North Dakota.” Gillam also presented “Effects of call structure on the jamming avoidance response in Brazilian free-tailed bats.” Bicknell and Gillam participated in a student honors poster presentation on “Impacts of wind energy facilities on North Dakota bats: biological and social implications,” regarding research that included Chris Biga, assistant professor of sociology.
Gillam’s research also has focused on investigating natural flexibility in bat echolocation and examining how bats adjust their calls in response to characteristics of their signaling environment. Information about her research was published recently in the Journal of Mammology and on Wired.com in the article, “How Bats Get Around the Crowded Skies – Hey, I’m flyin here!”
Bats use a natural type of sonar called echolocation to emit high frequency sounds that bounce off objects, which helps them determine size, shape and direction of their prey – mainly insects – and other objects. “It’s better than anything humans have come up with such as sonar,” says Gillam. Bats emit a loud sound, then measure the time it takes for the sound to bounce back, helping them determine how far away things are. Their echolocation can detect something as fine as a human hair in total darkness. Bats eat insects, including mosquitoes. Bats help agriculture in the United States by feeding on insects such as cutworms and corn-borer moths, and they pollinate more than 300 species of fruit.
Previous research by Gillam shows that bats can quickly shift the frequency of their acoustic pulses, many times in only about one-fifth of a second. This allows them to avoid signal interference from other bats or noises. It’s a type of built-in mechanism to avoid jamming of their communication signals.
Gillam’s research has been published in Proceedings of Royal Society B, New Scientist, Journal of Animal Behavior, Journal of Mammology, the New York Times and the PBS Kids program, “Dragonfly TV.”