Reduction of Western Wheatgrass by the Feeding of Two Rangeland Grasshoppers, Aulocara elliotti and Melanoplus infantilis1

Abstract

The avg reduction per day of western wheatgrass, Agropyron smithii Rydb., by 2 species of rangeland grasshoppers confined in field cages was: adult Melanoplus infantilis Scudder 35.3 mg; adult Aulocara elliotti (Thomas) 60.9 mg; 5th-instar A. elliotti, 39.8 mg; and 4th-instar A. elliotti, 17.9 mg. Forage loss from a density of 1 A. elliotti/m² was estimated to be 22 kg/ha. Food consumed and grasshopper weight were directly related. More forage was cut but not consumed by adult grasshoppers than by nymphs.