No self-respecting parent would raise a new baby on a diet of sugar alone. Instead, good parents are careful to give mothers milk or to mix formula containing all the energy and nutrients baby needs to grow.
Unfortunately, Mother Nature is not such a doting parent. In a study to be published in the November 30 issue of Nature, Arizona State University ecologist Jim Elser and his colleagues (see co-authors at end of this release) found that plant-feeding insects are provided with a diet so poor in nutrients that it impairs growth.
The researchers used basic chemical principles to evaluate the un-nutritious menu available for insects living in terrestrial habitats. They then compared it to the food available to plant-eating animals in lakes, where the animals seem to be literally swimming in nutrient-rich foods. The high quality of the aquatic diet gives diners the green light on rapid growth.
Elser, an aquatic ecologist, teamed with eleven other experts in aquatic and terrestrial ecology to do the study. The main goal was to find a means to compare aquatic and terrestrial food webs with each other, he says. Ecologists already know a lot about how nutrient balance affects food webs in lakes. They wanted to find out if the principles of aquatic nutrient balance could be applied to land environments.
The easiest place to start with this comparison is at the base of the food web plants and the animals that eat them. By looking at the interactions between plants and herbivores in lakes and on land, the researchers hoped to determine whether nutrient balance in food webs varies in different environments.
A fair comparison of these contrasting habitats, and the plants and animals that live in them, must be based on a common currency. They seem so different when you think about them microscopic algae in lakes and trees on land how do you compare these things? Elser asks. You have to find something they have in common, and what they have in common is
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Contact: James Hathaway
hathaway@asu.edu
480-965-6375
Arizona State University
28-Nov-2000