SAMPLING METHOD ASSESSMENT AND QUANTIFICATION OF TEMPORAL SHIFTS IN DENSITIES OF GRASSHOPPER SPECIES (ORTHOPTERA, ACRIDIDAE) BETWEEN WINTER-WHEAT, TRITICUM-AESTIVUM, AND ADJACENT RANGELAND
Rl. Gillespie et Wp. Kemp, SAMPLING METHOD ASSESSMENT AND QUANTIFICATION OF TEMPORAL SHIFTS IN DENSITIES OF GRASSHOPPER SPECIES (ORTHOPTERA, ACRIDIDAE) BETWEEN WINTER-WHEAT, TRITICUM-AESTIVUM, AND ADJACENT RANGELAND, Environmental entomology, 25(3), 1996, pp. 559-569
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.