Insect galls thrive on salt stressed big sagebrush host

The sagebrush steppe is estimated to occupy 4.4 percent of the total land area in the United States. In this ecosystem, the most common sagebrush species in most areas is big sagebrush, Artemisia tridentata. Big sagebrush provide a common host for galling insects. We observed that even in salt stressed environments big sagebrush grow and galling insects use them as hosts. In this study we test the hypothesis that there is a significant difference in insect gall density on salt stressed big sagebrush compared to unstressed big sagebrush. To test this, we collected data from four salt stressed sage plots and four unstressed plots at Columbia National Wildlife Refuge in Othello, Washington during 2010. We report significantly greater average gall density on plants in salt stressed plots. We collected four types of galls (artichoke, white fuzzy, black fuzzy, smooth, and other) and observed no significant difference in the diversity of galls on sage in salt stressed plots compared to the control. Further studies are needed to understand why salt stressed sage show greater density of galls, why insect galls seem to thrive on salt stressed sage.