Abstract
By using homozygous or heterozygous flies of two strains of Drosophila melanogaster, the effect of population density and fluctuating temperature on productivity (the number of progeny produced per female) was investigated. The results show that: 1) There were no differences in productivity between strains, but the productivity of homozygotes was smaller than that of heterozygotes in any condition. 2) The decrease of productivity under the fluctuating temperature was slightly larger in homozygotes than in heterozygotes. 3) Productivity was greatly influenced by population density and temperature, i.e., productivity was smaller under the fluctuating temperature and in the higher density than under the constant temperature and in the lower density. 4) Relative viability of homozygous flies measured by Cy/Pm method was stable for several changed environments. 5) There was a positive correlation between productivity and fecundity which is the number of eggs per female per day. From the results, relations between productivity and environments were discussed.
