Fun with Science Club®


			Plants determine the diversity of insects and predators. Beth Tyler 05.25.01 Insects depend on plants for food. When more food is available, more insects can exist. If there are more insects available to eat, then the number of insect-predators should also increase. Using this logic, four American scientists hypothesized that plant diversity would increase the diversity of insects and insect-predators. To test their hypothesis, the scientists killed all of the plants in a large field with chemicals. Then they burned the field and all its dead plants. They divided the field into over one hundred different areas, planting anywhere from one to sixteen plant species in an area. Two years later, the scientists sampled the insect and insect-predator populations in each different area of land. They swept a net through the plants several times, collected a sample of the organisms in that area. They identified the insects and insect-predators and counted the number of species. Finally, they compared the number of species of plants with the number of species of insects and insect predators. As they predicted, increasing plant diversity increases insect diversity and insect-predator diversity.


			Siemann, Evan, David Tilman, John Haarstad, and Mark Ritchie. 1998. Experimental tests of the dependence of arthropod diversity on plant diversity. American Naturalist 154(5): 738-750.