Short-term proteomic adaptations serve as an initial line of defence, allowing populations to cope with environmental changes before long-term genetic alterations occur. Using a representative set of genes, we examined how stress affects gene expression variability for different types and levels of abiotic stresses and how this influences population-level adaptation. Our data reveal that, depending on the nature of the stress, two distinct modes of response can be employed. In one, the levels of most proteins vary between individuals, leading to varied fitness levels in the population. In the other, a more limited range of expression is seen, and fitness is more even. This suggests different levels of complexity and plasticity in adaptation to different types of stress.