The Influence of Starvation on the Thermal Death-Point on Insects

Abstract

Experiments are described in which newly hatched larval lice (Pediculus humanus corporis) and adult C. fatigans were exposed to high temperatures. The humidity was controlled, and the exposures lasted for either 1 or 24 hours. Larval lice, whether fed or unfed, withstood 46.5° C. for 1 hour, while the Culex were much less resistant--they only withstood a temperature of 39° C. The humidity of the air did not affect these results. When exposed for 24 hours, larval lice which had fed withstood 38° C. in moist air. They only withstood 33° C. in dry air, as they were killed by desiccation at higher temperatures. Mosquitoes (C. fatigans) which had gorged gave similar results. They survived 37° C. for 24 hours in moist air, and only 32° C. in dry. Unfed lice or mosquitoes behaved differently, as they could not withstand such high temperatures for periods of 24 hours. This was because they had small food reserves, and at high temperatures their rate of metabolism was so increased that they died of starvation.