An Inventory of Arthropods from Three Rangeland Sites in Central Montana

Abstract

Three rangeland sites (mountain, foothill, and plains) in central Montana were surveyed for arthropods to determine their abundance and potential impact upon the vegetation. A vacuum quick trap (sampling method) showed that seven orders of arthropods were important on the basis of abundance and/or above-ground biomass: Acarina (mites); Thysanoptera (thrips); Collembola (springtails); Orthoptera (grasshoppers); Hemiptera (true bugs); Homoptera (leafhoppers and plant lice); and Hymenoptera (ants). The grasshoppers, true bugs, leafhoppers, and thrips consume parts of the plants and thus directly affect forage production. Springtails, mites (Oribatidae), and ants vary greatly in their habits and may affect forage production indirectly by breaking down organic matter in the soil or by affecting population densities of other insect species.