Grasshopper cage data: Vegetation Phenology and Grasshopper Competition

Vegetation was sampled at the termination of the experiment on June 25, 1989. Grasshopper densities outside the cages were sampled on May 23 and 24, 1989. After the first experiment, cages were set up on new plots 3m from the edge of the macroplot to avoid using vegetation disturbed by counting. On July 25, adult grasshoppers of two different species (Melanoplus femur-rubrum (FR) and Melanoplus bivattatus (BV)) were stocked according to the above treatments (randomly reassigned) in the following densities: FR by itself, 6/cage; BV by itself, 4/cage; FR and BV together, 4 FR and 3 BV /cage. Vegetation was sampled at the termination of the experiment on August 31, 1989.

In late May of 1990, grasshoppers were stocked in the following numbers in both fertilized and unfertilized plots: no grasshoppers (empty cages), AC by itself (5/cage), PA by itself (4/cage), and both species together (3 of each). With 8 replicates of each fertilizer x grasshopper combination, a total of 64 cages were used. Vegetation was sampled at the end of the experiment as in 1989.

In late July of 1990, two new grasshopper species were used in addition to Melanoplus femur-rubrum (MF): Phoetaliotes nebrascensis (PN) and Spharagemon collare (SC). Grasshoppers were stocked in the following numbers: no grasshoppers (empty cages), MF by itself (6/cage), PN by itself (10/cage), SC by itself (6/cage), MF + PN (3 MF and 5 PN per cage), MF + SC (3 of each per cage), SC + PN (3 SC + 5 PN per cage), and all three species together (2 MF, 2 SC, and 3 PN per cage). Vegetation was sampled at the end of the experiment as in 1989. At the end of the early and late 1990 experiments, a single soil sample was taken from each cage plot and analyzed for soil solution ammonium and nitrate with 0.02M KCl. For a list of treatments, see the treatment layouts in file trmte60.