The Mormon cricket is actually not a true cricket, but rather a shield-backed katydid. The common name derives from an invasion of the crops of Mormon settlers in the Salt Lake area in the mid-1800s.
We ran across plenty of these katydids on a recent hike although not in the numbers depicted in this video https://www.youtube.com/watch?v=Yy3dQJYquoY. While these insects can be quite destructive to crops they do eat the grasses and plants in natural rangelands much as large grazing mammals do (or did). I also find them quite interning to look at as each has subtle color variations.
Given these were not marching across our hiking trail in plague proportions I enjoyed seeing them on a late fall afternoon moving through the already dry grasses.