The GMR activity is conducted outside in the fall, in an open field that will remain undisturbed for 1-2 weeks. Students capture grasshoppers and mark them in a way that will not injure them. Mark off a grassy area that is 10m x 10m. Mark corners with flags. Two student collectors move through the site vigorously sweeping their nets through the vegetation.
Students begin at opposite sides of the site to avoid driving grasshoppers out of the sampling area.
Take the animals caught to the side of the sampling plot. Carefully open the net just enough to catch the grasshoppers one at a time. While one student holds a grasshopper, another puts a dot of nail polish or liquid paper on its thorax, being careful not to get the marking substance on the wings or the head. Put each grasshopper into the plastic container as it is marked. Repeat steps 2 and 3 two more times.