Combined effects of two mild stresses (cold and hypergravity) on longevity, behavioral aging, and resistance to severe stresses in Drosophila melanogaster

Mild stresses may have positive effects on aging, longevity and resistance to severe stresses at various ages in Drosophila melanogaster. However, no study has combined two mild stresses to know whether more positive effects would be observed than with each stress alone. Cold and hypergravity (HG) have positive effects on some traits, but negative ones can also be observed, particularly in females. This study combined in the same flies cold and HG exposure. When cold and HG had each positive or negative effects their combination had additive effects but, when only one of the pretreatments had some effect, the effect of their combination usually reflected this effect. Therefore, combining two mild stresses with positive effects on aging and longevity can be more efficient than each stress alone. However, if one of these mild stresses had negative effects and the other one positive effects, the net result of their combination could be the suppression of the positive effect of the second stress. On the whole, if the net result of the combination of two mild stresses would be negative, it would be preferable not to combine them.