Friday, October 26, 2012

Grasshoppers Frightened by Spiders Affect Whole Ecosystem

It seems that Insects have feelings after all! It has been proposed that the fear that exists in dead grasshopper corpses, play a role in the decomposition of other other dead things around them, such as grass. These dead debris are essential to the fertilization of new plant growth. Therefore, if the time it takes to re-fertilize new growth is increased, it will take longer for Mother Nature to automatically grow new things. The fear that exists in dead grasshoppers are displayed from the threat of predators, which in this case, are spiders. The stress that the grasshoppers undergo, boost the insect's metabolism and appetite for carbon-rich carbohydrates. After this chemical change occurs, the grasshopper carcass contain more carbon and less nitrogen. Less nitrogen causes problems for soil microbes because they need a good source of it to break down plant litter.
To test this hypothesis, researchers tested two groups of grasshoppers. One group consisted of stressed grasshoppers in the presence of spiders. The other group, the control, contained non-stressed grasshoppers. The scared grasshoppers had a higher carbon-to-nitrogen ratio than the non-scared grasshoppers possessed. To further the experiment, researchers placed plants near the remains of the grasshopper carcasses. The decomposition rate of the area where the non-scared grasshoppers were, was 62-200 % faster than the area of the scared grasshoppers.
Dr. Halwena concluded the experiment with this statement, "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. This has tremendous consequences for our ecological understanding of the living world" (Hebrew University of Jerusalem 1).http://www.sciencenews.org/view/generic/id/341454/description/Grasshoppers_terror_outlives_them
http://www.sciencedaily.com/releases/2012/06/120614142737.htm