- News Home
10 April 2014 11:44 am ,
Vol. 344 ,
The Pyrenean ibex, an impressive mountain goat that lived in the central Pyrenees in Spain, went extinct in 2000. But a...
Tight budgets are forcing NASA to consider turning off one or more planetary science projects that have completed their...
Ebola is not a stranger to West Africa—an outbreak in the 1990s killed chimpanzees and sickened one researcher. But the...
In an as-yet-unpublished report, an international panel of geoscientists has concluded that a pair of deadly...
Tropical disease experts tried and failed before to eradicate yaws, a rare disfiguring disease of poor countries. Now,...
Since 2002, researchers have reported that agricultural communities in the hot and humid Pacific Coast of Central...
Balkan endemic kidney disease surfaced in the 1950s and for decades defied attempts to finger the cause. It occurred...
- 10 April 2014 11:44 am , Vol. 344 , #6180
- About Us
A Nose for Survival
26 January 2005 (All day)
The robber crab is the world's largest land-living arthropod, weighing up to 4 kilograms, and it steals anything it can carry away in its formidable pincers. That's not the only amazing thing about the crab, say biologists. The crab evolved the ability to smell on land, just like insects do. "This is a really cool study," comments Leslie Vosshall, a molecular biologist at Rockefeller University in New York.
When the ancestors of robber crabs first walked out of their watery environment to live on land, their sensory equipment needed a makeover. The olfactory receptors on the antennae of marine crabs detect soluble, water-loving molecules. A landlubbing crab must zero in on molecules that waft through the air.
Bill Hansson, a chemical ecologist at the Swedish University of Agricultural Sciences in Alnarp, Sweden measured the electrical activity of olfactory neurons in the short antennae of robber crabs at Australia's Christmas Island while puffing scents over these sensory organs. Results of the tests indicate that the electrical activity in response to certain odors is the same in robber crabs as in insects.
This translates into similar senses of smell. Like insects, robber crabs are able to detect carbon dioxide, likely an adaptation for locating decaying meat, which releases copious amounts of the gas. Robber crabs also seem to have a high sensitivity for dimethyldisulphide, and specifically dimethyltrisulphide, which are the same carcass odors that attract insects to animal remains. The researchers report their results in today's issue of Current Biology.
Hansson calls the robber crab's development of a bug's nose "a great example of convergent evolution." He adds, "The robber crabs have reinvented their smell for land so remarkably that they can even smell water."