Plant‐Animal Interactions: Studies of the Effects of Grasshopper Grazing on Blue Grama Grass

Abstract

Results of a laboratory experiment where we measured the influence of grasshoppers (Melanoplus sanguinipes) feeding upon leaves of hydroponically grown blue grama grass (Bouteloua gracillis) are presented. Performance of both the plant and animal conditions are given: growth rate of the plants held at three temperatures, amount of food ingested by the grasshoppers, digestive efficiencies, weight change of grasshoppers, the amount of litter cut, and the pH change of the root medium. The experiment indicates that thee are plant processes triggered by grasshopper feeding which result in increased energy transport levels within the plant. Most of this energy expenditure occurs in the belowground complex of the plant. Moreover, regrowth potentials of the plant on which grasshoppers had been feeding is much higher than for plants that had simply been clipped. Hence, we suggest that perhaps the largest single effect displayed by aboveground insect grazers on grassland ecosystem plants (viz., grass) is the increase in belowground respiration and root exudation.