She and her colleagues had predicted this after building a large model of the tiny hairs on a lobster nose and swishing it through Karo syrup, a set-up that mimics the physics of swishing real antennules through water. These experiments showed that water does not flow between the sensory hairs unless the antennule moves very rapidly - at the speed of the flick downstroke.
What this means is that, in the lobster's real world, small differences in odor concentration in a plume are preserved and captured by the array of hairs, though it is unclear whether the lobster can take advantage of this detailed information.
"It's clear that very detailed information does get into the receptor area when the lobster sniffs," Koehl said. "The next step is to figure out if it is using that information."
This will involve working with neuroscientists who can help relate odor concentration in the hairs to electrical signals triggered by the hairs. Much work has already been done on the nervous system of spiny lobsters, one reason Koehl chose to study them.
Koehl's lobster work is one of her many projects on the boundary between biology and engineering, where she seeks to discover the physical principles embodied in biological design.
"When you look at the animal kingdom, you see lots of creatures that capture odor from water or air using antennae that are feathery or hairy," Koehl said. "We want to know how these feathery structures interact with water or air when the creatures fly or sit in a current to catch molecules, and which aspects of their design affect how they perform at catching odors."
Earlier this year, she and Catherine Loudon, a former postdoctoral student now at the University of Kansas in Lawrence, described how the silkworm moth uses its wings to fan odors efficiently through its feathery antennae. Koehl and her UC Berkeley colleagues also study the hairy noses of crabs
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Contact: Robert Sanders
rls@pa.urel.berkeley.edu
510-643-6998
University of California - Berkeley
30-Nov-2001