Thu 16 Jun 2011
By Amanda Rose Martinez
Venture into the Grass Lab this summer on the second floor of Rowe and you’re liable to hear the amorous calls of singing fish.
This week, Liz Whitchurch, a 2011 Grass Fellow who hails from the University of Washington, was busy building the fictitious nests she’ll use to study the auditory behavior of plainfin midshipman, a type of fish that sings to attract its mates.
Whitchurch sets the scene. On spring nights all along the West Coast, randy, male midshipman flood the intertidal zone. They rapidly contract a muscle on their swim bladder, which results in a low, resonant hum that lady midshipman find irresistible.
“They’re calling to the females: ‘Come lay your eggs in my nest,’ ” says Whitchurch. “And the females, out there somewhere in the water, then have the task of localizing that call.” They zero in on the male whose call is most alluring and lay their eggs in his nest. The male then cares for the eggs for the rest of the summer. All told, not a bad deal.
“These fish are really interesting because they rely entirely on their auditory sense to reproduce,” Whitchurch explains. But while scientists have observed how the midshipman’s brain encodes sound underwater, to date, studies have only looked at immobilized fish.
“The whole idea is to understand how auditory cues are encoded in the brain while these fish are actually swimming around,” says Whitchurch, who plans to measure the phenomenon for the first time by monitoring midshipman in a six-foot-diameter tank in the MBL’s Marine Resources Center. “If you understand how fish navigate using sound, you can imagine building machines that navigate in the same way,” she says.
In a lab upstairs, Grass Fellow Raquel Vasconcelos, from the University of Lisbon, is investigating the behavior of a different singing fish—the toadfish. Emitting sounds that conjure a boat horn, male toadfish also depend on vocalizations to woo their would-be mates.
Hunched over a machine designed to mimic minute sound vibrations that occur in the ocean, Vasconcelos prepares to insert an electrode into the nerve of an anesthetized toadfish, staged on the machine’s surface. Richard Fay, an expert on fish hearing and a summer fixture at MBL since 1993, lends a hand.
“We think that the fish ear is stimulated not by sound pressure, as in human hearing, but by the motion of sound particles,” explains Fay. In the natural environment, when sound passes through the fish, it moves in the direction of that sound.
In studying how toadfish nerves respond to sound vibrations, Vasconcelos hopes to better understand how the fish ear processes auditory feedback or background noise in the water, and how such feedback may affect the toadfish’s vocal, and thus, mating behavior. “There’ve been a lot of studies about auditory feedback in birds,” Vasconcelos said, “but as far as I know this would be the first that looked at fish.”
“Firsts” and other research innovations are an enduring theme at the Grass Lab, which for 14 weeks every summer since 1952 has served as an oasis for burgeoning leaders in the field of neuroscience. It’s an oasis in the sense that it affords its fellows the chance to fiercely pursue their research goals, while in the company of distinguished peers, using state-of-the-art equipment, and with little threat of distraction.
“What distinguishes it from their home labs,” says Felix Schweizer, a ‘94 Grass Fellow who currently serves as the Lab’s co-director, “is that the preparations they’re working on are all very different, which is exciting, right? Most of these preparations are things that we’ve heard about, like the toadfish. But in my lab, for instance, you would never see a toadfish. And then you come here and you see all of these classic things going on—people who do molecular work or maybe more biophysical work. And then suddenly they’ll hear something about animal behavior that they never really thought about.”
It’s this exposure to diverse disciplines that can profoundly impact the way that Grass Fellows think about their work. The result is often original perspectives and novel research methods that have bequeathed the Grass Lab its reputation for creativity. “It’s a very unique environment to do science in,” Schweizer says.
To apply for a Grass Fellowship, please visit: www.grassfoundation.org. Application deadline is December 5th.