干旱区生态环境知识资源中心

1. To make the most effective use of evaporative cooling, an insect must be in an environment of the lowest humidity.

2. To test the hypothesis that, at temperatures requiring evaporative cooling, grasshoppers were able to select such a favourable environment, we observed the selection of, and time spent in dry (RH less-than-or-equal-to 5%) or humid (RH greater-than-or-equal-to 97%) alternative chambers of a shuttle box at a range of temperatures from 28 to 50-degrees-C, in two species, Schistocerca americana and Romalea microptera.

3. Below 45-degrees-C, both species tended to remain in the chamber in which they began the trial; above 48-degrees-C, they all selected the arid chamber.

4. These findings suggest that grasshoppers can select the environment best for maintaining their body temperature below lethal levels but do not necessarily mean that they can actually sense relative humidity.