Metabolism and thermoregulation in desert and montane grasshoppers.

Temperature regulation and oxygen consumption were examined in two species of grasshoppers: Melanoplus sanguinipes from cold alpine tundra at elevation 3,800 m, and Trimerotropis pallidipennis from hot desert habitats at elevation 250 m. Both species utilized behavioral thermoregulation to keep body temperature (T ) more constant than environmental temperatures (T ) during the day. The difference in average T in the two species was much less than the difference in T 's. Microclimate measurements indicate that temperature regulation is not difficult for M. sanguinipes, but T. pallidipennis must restrict activity for much of the day to avoid heat stress and can easily overheat if it moves into sunlit areas. Oxygen consumption ([Formula: see text]) at average T and total daily energy expenditures are higher in M. sanguinipes than in T. pallidipennis, as is the Q for [Formula: see text]. These differences may be related to different strategies for energy utilization and predator avoidance.