Frightened grasshoppers leave their mark on the Earth
Studies show that the body composition of a scared grasshoppers changes — the carbon-to-nitrogen ratio is about 4 percent higher than their calmer peers — meaning it breaks down differently in the soil.
Thu, Jun 14 2012 at 3:41 PM
GRASSHOPPERS: This rather tiny difference caused plant matter to decay much more slowly than it did in comparison tests using grasshoppers who died more peacefully. (Photo: Karen Bleier/AFP)
Grasshoppers who die frightened leave their mark in the Earth in a way that more mellow ones do not, U.S. and Israeli researchers said this week.
"So, indeed this sounds a little bit weird," lead author Dror Hawlena said in an audio interview posted on the journal Science's website on June 14.
Hawlena, a researcher at the Hebrew University of Jerusalem, along with colleagues at Yale University, devised a test to measure the legacy of grasshoppers that were scared by spiders.
They placed cages in areas of natural vegetation and allowed some grasshoppers to be alone while others were placed in cages with a spider.
They glued the mouths of the spiders shut in order to make sure that the grasshoppers experienced pure fear but were not actually killed by the predators.
When the grasshoppers died, Hawlena took their bodies back to the lab and deposited them in soil.
He found that the body composition of the frightened grasshoppers was changed — their carbon-to-nitrogen ratio was about 4 percent higher than their calmer peers.
But that rather tiny difference caused plant matter to decay much more slowly than it did in comparison tests using grasshoppers who died more peacefully.
Hawlena said the findings shed light not only on how predators and prey influence the makeup of the soil, but how stresses invoked by drought and extreme heat might have lasting effects on crops and growth cycles.
Copyright 2012 AFP Global Edition
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