Forage Losses Caused by the Grasshopper Aulocara elliotti on Shortgrass Rangeland

Abstract

A field-cage study was conducted in 1973 and 1974 to determine the amount of forage (mainly grasses) destroyed by different population densities of the grasshopper Aulocara elliotti. The amount of forage consumed during the third instar and through the adult stage averaged 34.5 mg of forage per grasshopper per day. Thus, an estimated loss of 23.1 lb of forage per acre will result from a density of one Aulocara/m2 if the grasshopper lives for 75 days (45 days as a nymph and 30 days as an adult). Based on total available forage (standing dead and new growth), a 63% forage loss was recorded in 1973 at one site and losses of 26% and 29% at two sites in 1974 resulting from about 20 grasshoppers/m2. Severe grazing by grasshoppers also resulted in reduced production of forage during the subsequent (1974) season.