A test of simple models of population growth using data from very small populations of Drosophila melanogaster

Three simple discrete-time models of density-dependent population growth we re fit to data from eight small laboratory populations of Drosophila melano gaster subjected to either stabilizing or destabilizing food regimes. The e xponential logistic model gave the best fits to data from both types of pop ulations. In contrast, the linear logistic and hyperbolic models did not yi eld good fits, especially in the case of the destabilized populations. Para meter estimates from the exponential logistic model were in close agreement with those from previous studies using very large Drosophila populations s ubjected to the same type of stabilizing and destabilizing food regimes. Ou r results suggest that the simple exponential logistic model can reasonably well capture the major features of the dynamics of Drosophila populations even for very small population sizes where one may expect demographic stoch asticity to play a major role in determining the population size.