This experiment, located out in garden area, is designed to set up permanent grasshopper populations on different combinations of two plant species: Andropogon gerardi and Solidago rigida. The experiment involves 150 plots with 10 different grasshopper treatments: (1) no grasshoppers (empty cage) (2) Arphia conspersa (AC) by itself (3) Pardalophora apiculata (PA) itself (4) AC and PA together (5) Melanoplus femur-rubrum (MF) by itself (6) Spharagemon capillare (SC) by itself (7) MF and SC together (8) AC, PA and MF together (9) AC, PA and SC together (10) AC, PA, MF and SC together.
Two male-female adult pairs of each species will be introduced into each 1m2 cage in the summer of 1991 and additional grasshoppers will be added to ensure the initial viability of each grasshopper population. Vegetation will be sampled by clipping 60 x 5cm strips each August (only empty cages will be sampled in 1991). In addition, soil solution concentrations of ammonium and nitrate will be sampled from each plot in May 1991 and September of all ensuing years.
Finally, counts of adults and nymphs in each cage will be made in June and August in 1992 and each year thereafter. For a list of treatments, see the treatment layouts in file trmte77.