SAMPLING METHOD ASSESSMENT AND QUANTIFICATION OF TEMPORAL SHIFTS IN DENSITIES OF GRASSHOPPER SPECIES (ORTHOPTERA, ACRIDIDAE) BETWEEN WINTER-WHEAT, TRITICUM-AESTIVUM, AND ADJACENT RANGELAND

In this study, we determined that 2 sampling methods (D-Vac and sweep net) taken al weekly intervals could be used to sample grasshopper spe cies across 2 adjacent habitats of winter wheat and rangeland. We also quantified temporal density estimate shifts between winter wheat, Tri ticum aestivum L., and rangeland by migratory grasshoppers, Melanoplus sanguinipes (F.), twostriped grasshopper, M. bivittatus (Say), and Pa ckard grasshopper, M. packardii Scudder, all 3 species coinhabit these areas. Specifically, at 4 study sites with the highest grasshopper de nsities there were significant seasonal shifts in density estimates of these species between winter wheat and rangeland suggesting that thes e species dispersed between habitats. At a 5th site, sweep net samplin g detected a shift in density estimates between habitats by M. sanguin ipes and D-Vac sampling at this site suggested there was a similar tre nd. At 4 study sites such shifts in density estimates did not occur su ggesting that no dispersal occurred or it was not detectable at these sites using our sampling methods. In all but 1 case the density of the se species, were lower than those where density estimate shifts occurr ed.