TEMPERATURE AND LENGTH OF LIFE IN DROSOPHILA

1. (1) The length of life of Drosophila subobscura adults decreases with rise in environmental temperature. Above 37°C death is virtually instantaneous while at 0°C it is estimated, by extrapolation of the data, that the flies would live 2·7 years. 2. (2) Around 28-29°C appears to be a critical point in the temperature-length of life relationship. Below this point the activation energy of life-shortening (Arrhenius μ) is 22 kcal/mole, while above this point it is 182 kcal/mole. 3. (3) The existence of a critical point in the temperature-length of life relationship indicates that the higher temperatures are life-shortening because they cause events which do not occur at the lower temperatures. The possible mechanisms operating at the higher temperatures are discussed. © 1969.