Linking Behavior, Genetics, and Evolution
Jeffery's research team showed how an adaptive behavior found in blind cavefish that gives them an advantage in locating food in the dark is linked to a genetic trait. "Vibration Attraction Behavior" (or VAB) is the ability of fish to swim toward the source of a water disturbance in darkness. Postdoctoral associate Masato Yoshizawa measured this behavioral response in both wild caught and laboratory raised cave and surface-dwelling fish using a vibrating rod at different frequencies as a stimulus. Most cavefish displayed VAB and would swim toward the vibrating rod and poke at it, while few surface fish did.
This behavior is advantageous for feeding success in the dark caves where food sources are limited and large predators are absent. "Outside the cave, however, there are many predators," explains Jeffery, "and indiscriminately going to a vibration would be a certain risk for predation for a surface-dwelling fish."
The cavefish responded most frequently and strongly to a vibration at a frequency of 35 Hz. "This frequency falls within the range that is detected by the superficial neuromasts," explained Yoshizawa. "These specialized hair cells are part of the fish's lateral line, which is the sensory organ used to detect movement and vibration in the surrounding water."
To confirm the role of the superficial neuromasts (SN) and the lateral line, Yoshizawa measured the VAB after he inhibited the function of the superficial neuromasts in both cavefish and surface fish. "I used a non-toxic glue on their cheek regio
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University of Maryland