STARVATION AND DESICCATION TOLERANCE IN DROSOPHILA-MELANOGASTER - DIFFERENCES BETWEEN EUROPEAN, NORTH AFRICAN AND AFROTROPICAL POPULATIONS

Starvation tolerance (mean survival time with water only) and desiccation tolerance (mean survival with no food and zero % humidity) were measured at 17-degrees-C in adult flies from 3 different geographic populations living in different climates. A fairly large uncontrolled variability was observed and two successive generations of the various isofemale lines were investigated for each population. For desiccation tolerance, a Tunisian population from an oasis was found to be more tolerant than French or Congolian populations. For starvation tolerance, the survival of the Congolian population was about twice the values found for French or Tunisian flies. It is suggested that the Afrotropical flies which live in a hot, humid environment, are poorly protected against desiccation but need a high starvation tolerance because of their high metabolic rate due to the high ambient temperature.