Grasshoppers Frightened by Spiders Affect Whole Ecosystem
Means 'Tremendous Consequences' for the Environment, Say Scientists
Grasshoppers scared by spiders are revealing the lasting effects predators can have on the Earth's ecosystem. Scientists discovered that scared grasshoppers eat far more plants then they normally would- eventually causing organic materials to decompose nearly half as fast as they should.
The experiment was done by Dr. Dror Halwena of the Department of Ecology, Evolution and Behavior at the Alexander Silberman Institute of Life Sciences at the Hebrew University of Jersusalem along with scientists from Yale University in the U.S. They teamed up to find out that the loss of an ecosystem's predators can have profound consequences.
Researchers found that when a grasshopper is scared, it eats more plants high in carbohydrates, which actually changes the insects' biological makeup. When the stressed out grasshopper dies, it's body- now containing less nitrogen because of the stress diet- gives less nitrogen to the soil, whose microbes in turn decompose organic material much more slowly.
Get Our Latest News for FREE
In layman's terms, fear of predation in animals slows down decomposition in plants. Regular, unstressed grasshoppers, in comparison, help decompose soil 62 to 200 percent faster. The problem, says Halwena, is that many natural habitats are losing their predators at an increasingly fast rate.
"We are gaining a greater understanding of the necessity of conserving all of the component parts of the ecosystem in general and of predators in particular. We are losing predators in nature at a much faster rate than others species," the scientist said in an audio recording with the study, which was published in the Science journal.
The Hebrew University and Yale University researchers' find is significant because it shows how every change in an ecosystem- no matter how small- can affect it in lasting ways. We now have further insight into how disasters like drought and extreme heat affect nature.
"We are dealing here with an absolutely new kind of mechanism whereby every small chemical change in a creature can regulate the natural cycle, thus in effect affecting the ecology in total, such as the amount of carbon dioxide released into the atmosphere (through decomposition) and field crop productivity," posited Dr. Halwena.
"This has tremendous consequences for our ecological understanding of the living world," the scientist added.
