Thermoregulation of an unusual grasshopper in a desert environment: The importance of food source and body size

1. 1. The black cone-headed grasshopper, Poekiloceros bufonius, lives in hot, arid environments. Its diurnal behavior exposes it to direct sunlight. 2. 2. P. bufonius is able to withstand the poisonous sap of its food plants and thus may have an abundant water supply available to it. The sexual dimorphism of the species suggests the 5 × larger females may have an advantage in water storage over the males. 3. 3. Both genders were able to depress their internal temperatures below the higher temperatures of their environment by evaporative cooling. 4. 4. The males lost proportionately more water by evaporation, produced drier feces and may be more constrained by water availability. The females appears to be more profligate with their water reserves which supports the idea that large body mass may be an advantage to an insect in the desert.