OBJECT OF THE MONTH - DECEMBER 2006
Grasshoppers in December? in Colorado?
A specimen of Arphia pseudonietana collected in Boulder, Colorado on December 2, 1960 by Gordon Alexander (UCMC 0022862)
Unusual, yes, but not unheard of. Although not typical for Colorado, this male specimen of Arphia pseudonietana, the northwestern red-winged grasshopper, was found in Boulder on December 2, 1960. Clearly, he lived a long life in grasshopper terms. Had this grasshopper not been collected and added to the Museum's collections he certainly would have succumbed to starvation. It is one of just a handful of specimens in our collections that was taken in Boulder in December.
A. pseudonietana are generally 3-4 cm in length and feed mostly on grasses, though they will eat broad-leafed plants as well. They can fly straight and silent, or they have the ability to crepitate in flight (make a clicking or crackling noise). When spooked, they burst into noisy flight. Their path is erratic as they flit and flutter through the air. Then, they dive straight down and disappear into the grass where they sit silently, watching. This animated flight and the bright reddish color of the hindwings make them appear more like butterflies than grasshoppers.
In Colorado (and most of the western United States) there is a closely related species, Arphia conspersa, the speckle-winged rangeland grasshopper. A. conspersa tends to be slightly smaller (2-3.5 cm) than A. pseudonietana, but there is much overlap in size. In fact, it can be difficult to distinguish these two species. The morphological differences between them are subtle. Like A. pseudonietana, they eat primarily grasses, and the adults may also crepitate in flight. In Colorado, some individuals of A. conspera have red hindwings while others have yellow.
Three specimens of two different species of grasshoppers. The specimen on the left is Arphia pseudonietana (UCMC 0013104). The specimens in the middle and on the right are Arphia conspersa (UCMC 0013793 red-winged form) and (UCMC 0013775 yellow-winged form).
It is interesting that two closely related species that live in the same area are reproductively isolated. In the case of these two Aprhia species, it has to do with development. A. pseudonietana adults appear late in the season (August-December?) whereas A. conspersa are adults in April-June. The two species are not adults at the same time.
There are other differences as well. As a species, A. pseudonietana spend the winter as eggs tucked into the soil in groups of twenty or so, hatching into nymphs (juvenile stage) in the spring. A. conspersa on the other hand, hatches in the fall and spends the winter as nymphs. Amazingly, the nymphs do not freeze to death during the winter months, but continue their development into adults once the spring warms and the grasses sprout.
For more information on Colorado's grasshoppers you might wish to look at the following websites:
Grasshoppers of Colorado: Identification, Biology, and Management
Field Guide to Common Western Grasshoppers
Or check out these interesting books on grasshoppers:
Field Guide To Grasshoppers, Katydids, And Crickets Of The United States by John L. Capinera, Ralph D. Scott, and Thomas J. Walker
Locust: The Devastating Rise and Mysterious Disappearance of the Insect That Shaped the American Frontier by Jeffrey A. Lockwood
