Tuesday, March 22, 2011

Several Signs of Spring

There has been a flurry of activity in the Yellowstone River Valley as days become longer and the earth warms up. Recent weeks have brought the return of belted kingfishers, mountain bluebirds, great blue herons, sandhill cranes, and red-winged blackbirds. The painted turtles have woken up out of hibernation in the deep mud beneath Will's Marsh.

On a recent trip to look at schoolyard wildlife in Pryor, students found several grasshoppers. There are over 400 species of grasshoppers in the 17 western states. Grasshopper embryos suspend growth in the fall and enter a period of diapause (a dormant period). As the earth warms in the spring, the embroys continue growth and hatch out of their eggs. The diapause ends when soil temperatures reach an average of 50 - 55 degrees F. Grasshoppers undergo simple metamorphosis, as opposed to complete metamorphosis seen in butterflies and the majority of other insects. The insect that hatches out of the egg is called a nymph. It looks like the adult except that it is smaller and does not have wings. Young grasshoppers shed their skin as they grow from the nymph stage to adulthood.
Grasshoppers eat primarily grasses, though some species also eat forbs. They can be a destructive force on farmer's crops during years when the population swells. For a complete discussion of this fascinating insect, visit the USDA's online Field Guide to Common Western Grasshoppers.