Ecology 7th Edition by Manuel Molles

Exercise 19

The body temperature of the seashore isopod Ligia oceanica is 30°C under stones, where the relative humidity is 100%, but 26°C on the surface, where it is exposed to full sun and the relative humidity is 70%. Edney (1953) proposed that the isopods in the open had lower body temperatures because they evaporatively cooled in the open air. Explain why evaporative cooling would be effective in the open air but nearly impossible under stones.