Adults of a French Drosophila melanogaster strain were kept without food in humid and dry conditions and survival time was measured at nine different temperatures ranging from 5 to 31°C. A temperature decrease resulted in an exponential increase of life duration, as would be expected from a slower utilization of reserves. This phenomenon did not extend over the whole temperature range: below a given threshold (around 11–14°C) the exponential increase was not observed and a reduction of life duration occurred at very low temperatures. This result demonstrates some specific, deleterious effects of cold. In the presence of water, starved males always survived longer than starved females. Under desiccating conditions, females survived longer except at very low temperatures, where males survived longer. Survival with water was always much longer than in dry conditions but the ratio of survival time in humid air over survival time in dry air, which is an accurate estimate of tolerance to desiccation, varied according to sex (it was higher in males) and to temperature (it was lowest at middle temperatures). Weight analyses suggested that at medium temperature (25°C), individuals in the presence of water exhausted about 37% of their initial dry body weight before death and died from starvation. Though desiccated flies used only 12% of their reserves before death, the hourly rate of dry weight loss remained the same in both conditions. At 5°C, death occurred in both conditions before the reserves had been thoroughly used.