Ecological Correlates Between Rangeland Grasshopper (Orthoptera: Acrididae) and Plant Communities of Southern Idaho

Abstract

Grasshopper and plant community relationships in southern Idaho were examined within a life–history context. Plant species composition (by weight) and density and species composition of grasshoppers were estimated at 52 sites in south–central Idaho, representing a range of plant communities from native sagebrush–bunchgrass to exotic annual grasslands.The plant community at each site was evaluated using the Grime triangular model of plant life–history strategies,which consists of 3 axes representing adaptations to competition, stress, and disturbance. Four attributes were measured for the 20 most common grasshopper species: mean density, habitat breadth, average instar in June, and diet breadth. Grasshopper density, habitat breadth, and diet breadth were correlated positively with site scores on the disturbance axis of the Grime life–history model and were correlated negatively with site scores on the competition and stress axes. Results suggest that characterization of grasshopper and plant community life–history strategies provides useful insights for understanding the dynamics of grasshopper assemblages from different habitats.