This experiment is designed to show the ability of different grasshopper species to eat and assimilate different plant species. The grasshopper species tested were adults of Arphia conspersa and Pardalophora apiculata in June, nymphs of Melanoplus femur-rubrum and Melanoplus bivittatus in July, and adults of Melanoplus femur- rubrum, Melanoplus bivittatus, and Spharagemon collare and nymphs of Phoetaliotes nebrascensis in August.
Plants tested were graminoids Cyperus sp., Schizachyrium scoparium, Poa pratensis, unfertilized Agropyron repens, and fertilized Agropyron repens, and forbs Solidago nemoralis, Solidago rigida, Hieracium longipilum, Liatris aspera, and Lespedeza capitata.
Ten of each grasshopper species were placed individually in one liter jars after four hours without food (to clear the digestive tract). Cut leaves of each plant species were preweighed and placed in water-pics and then placed in the jars with grasshoppers. Food was removed twelve hours later, followed by the grasshopper and any feces four hours after that. Remaining food and feces were dried at 50 degrees C and later weighed. All trials were conducted indoors at 27 degrees C. Dry mass eaten by each individual grasshopper was determined by subtracting the dry mass of plant remaining from the product of the original plant wet mass and the proportion dry mass for that plant species (measured on the day of the feeding trial). Assimilation efficiency was determined from the dry mass of feces relative to the dry mass eaten.