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Listening for bats

Biology professor shares her unusual enthusiasm with students

By Steven Blodgett

Lawrence Today magazine, Fall 2004

Photo of a batHer students fondly call her the “bat lady” or simply “Batwoman.” A feature article in the Appleton Post-Crescent in March, titled “Holy bat detector: Lawrence professor immersed in the world of bats,” noted that, while she hasn’t yet found a way to take wing, she regularly puts on the ears of a bat through the use of a “bat detector” to hear the nocturnal symphony of the bat world.

Clearly, Jodi Sedlock, entering her third year at Lawrence as assistant professor of biology, is quickly making a name for herself, both on and off campus. I caught up with her in Youngchild Hall before her planned departure for a one-month field trip to the Philippines in August, where she would again haunt the tropical forests on Mount Banahaw in southeastern Luzon in search of the objects of her affection.

As a young adult, Sedlock wasn’t particularly enamored of flying mammals or even with science for that matter. A Wisconsin native, after graduating from Waukesha North High School she attended the Center for Creative Studies in Detroit and then the School of the Art Institute of Chicago, to study drawing, design, and painting.

While at the Art Institute, she happened to accept a co-op position with the Mammal Division of the Field Museum, which serendipitously ended up changing her career path. Using her artistic talents, she became an illustrator in the bat collection and found herself drawing bat skulls to her heart’s content. That, in turn, sparked her interest in ecology and biology, and finding a mentor at the museum led her to a love of not only bats but of science. Her association with the Field Museum continues to this day, having grown from a relationship first as an undergraduate, then a graduate student, and now as a professional research associate.

For several years now, her laboratory has been the Philippine archipelago, first for the completion of her University of Illinois at Chicago doctoral dissertation on the ecology, community organization, and conservation of insectivorous bats and now for a long-term population study of the bat communities of the Philippines.

"The Philippines is a unique place in the world in terms of biodiversity. First, it is in the tropics, where species diversity increases as you move closer to the equator because of longer growing seasons and the stability of food sources across seasons. Second, it is an archipelago, one that has changed over millions of years as glaciers melted and sea levels rose, breaking land masses into smaller parts,” says Sedlock. “Archipelagos like the Philippines have high endemicity, meaning that a large number of species are found only there and nowhere else in the world. As highland areas turned into islands, animal populations and plant populations also were broken up and over time evolved into new species.”

Sedlock is currently engaged in a project documenting and describing the diversity and distribution of insectivorous bats in the Philippines. She is also interested in studying the communal ecology of bats from a conservation perspective, to learn how many bat species are able to co-exist simultaneously within certain habitats and how humans’ alteration of the environmental landscape, such as through deforestation, may affect species diversity.

"Of all of the mammals in the Philippines, insectivorous bats are rather poorly known,” observes Sedlock. “In large part, that is simply because they are very difficult to study.” Fruit bats, which use their eyes to forage for prey, can be trapped in mist nets and physically studied with relative ease. Insect-eating bats, which use sound to orient themselves, deftly avoid being captured in nets. “In the Philippines, we learned a lot about fruit bats very quickly,” she adds. “Insectivorous bats, however, have proven very illusive, so we have had to come up with different ways of studying them.”

To catalog the bat species she researches, Sedlock utilizes an acoustic device, a so-called “bat detector,” to fingerprint their echolocation calls by bringing the frequencies down to the audible range of humans. Echolocation is how certain bats use sound to “see” or find their prey.

Insectivorous bats send out through their noses or mouths distinct calls that are unique to each species. When the sound bounces off an insect or picks up the beating of the insect’s wings, it “echos” back to the bat, which can then hone in on its dinner. Different echolocation signals are used by different species for finding different feeding targets.

"Just as all birds have different calls, we can recognize bats by their unique calls,” explains Sedlock. “When we think of resource partitioning and species specialization, we often think of the Galapagos Islands and the finches that live there. They are a wonderful example of evolutionary adaptation — different finches with different-sized bills go after different food sources. A large-billed finch, for example, will be more efficient at eating large seeds and draw upon that as its food source.”

For insectivorous bats, the species specialization is in the attributes of their echolocation call, which can vary in frequency or pitch, the duration of the call, the time between calls, and the overall intensity of the call. “Depending on the frequency, duration, or intensity, one bat might be more adept at foraging in one habitat type than another,” says Sedlock. “A bat with a higher pitch, for instance, is more efficient at foraging for smaller insects.”

Beyond being intrinsically interesting to her as a scientist and bat aficionado, Sedlock’s research has broader ramifications, not only through the sharing of her work within the scientific community — the species collections from the taxonomy work she is doing in the Philippines are donated to the Field Museum — but also in her teaching at Lawrence.

"I always use my research in my teaching,” she says. “In teaching the course Conservation Biology, for example, I often draw upon my firsthand experiences with conservation agencies in the Philippines and elsewhere to elaborate on a point.”

"In my Terrestrial Field Ecology course, one of the hands-on projects the students do is a bat study. I have students go out with bat detectors and map the big and little brown bat populations of forest preserves in the Appleton area,” explains Sedlock. “They use the bat detectors to obtain acoustic samplings and identify species, then generate hypotheses as to where they would expect these bats to be.” Students in the course also go up to Björklunden for a weekend each year to net bats. “We go out on two nights and trap bats, and the students compare their observations with the field work they have been engaged in around Appleton.”

Sedlock also taught a tutorial on bat ecology for the second time this past spring, with five students enrolled. One of her students, Kelly Scheer, ’05, from Lisbon, Iowa, spent the summer living at Björklunden, conducting an independent study project that mapped bat activity across the Door County landscape. Sedlock hopes to work with Scheer in correlating the student’s findings with the research the professor has been doing in the Philippines.

“Last summer, I brought two Lawrence students, Rachel Gates, ’06, Mahtomedi, Minnesota, and Christina Balch, ’03, Hollandale, who had just graduated, with me to the Philippines,” says Sedlock. “It was a wonderful opportunity for them to experience field work in the tropics, even with the wild pigs, pit vipers, and trekking uphill all the time on forest paths that were overgrown or even non-existent. Next year, I plan on taking two students with me as well.”

Perhaps the best indication that Professor Sedlock’s enthusiasm for bats is infectious among her students, is the fact that a number of biology students have opted to sign up for independent study to work with her on diet analysis. Diet analysis is a polite way of saying that these student scientists are sorting through loads of bat guano — dried bat droppings — brought back from the Philippines, examining the guano through a microscope in order to identify specific insects from their parts and help determine the bat’s food source. “Because of the detailed nature of trying to identify the insect remains, it can be quite tedious work,” says Sedlock with wry humor, “but some students really enjoy it, because it is like putting together a puzzle.”

In summing up why she so enjoys sharing her bat fascination with her students, Sedlock puts it this way, “I don’t know if bats can really teach us humans anything new, but what they can do is inspire us to open our minds and think in a different way. When you learn about how bats perceive the world, it forces you to step out of your own terrestrial vision-centered life and see things in a different way, to come to appreciate those bizarre aspects of nature that we so quickly want to write off.” And, she is quick to add, “Yes, it can be a challenge. Not everybody thinks bats are cute.”