People throughout the midwestern U.S. can anticipate the “sudden” appearance of large numbers of grasshoppers. Some people will attribute the sudden appearance to the recent bout of hot weather, which certainly increases rate of development, but the reality is that the grasshoppers have been developing for months.
The younger nymphs of several common species (e.g. red-legged grasshoppers and differential grasshoppers) are green, blending easily with a variety of plants that provide them food and shelter. The earlier stage nymphs respond to potential predators by moving to the opposite side of a leaf or stem. We simply don’t see them.
As the nymphs approach maturity, the later stage, more powerful nymphs molt into green-brown individuals who respond to potential predators by jumping rather than hiding.
Adult coloration, comprised largely of browns and grays, allow the adults to blend more easily into the drying vegetation and foliage that will become more prominent over the next several weeks.