Data from: Variable stressor exposure shapes fitness within and across generations

Environmental variation has long been considered a key driver of
evolutionary change, predicted to shape different strategies, such as
genetic specialization, plasticity, or bet-hedging to maintain fitness.
However, little evidence is available with regards to how the periodicity
of stressors may impact fitness across generations. To address this gap, I
conducted a reciprocal split-brood experiment using the freshwater
crustacean, Daphnia magna, and an ecologically relevant environmental
stressor, ultraviolet radiation (UVR). I exposed one group to constant and
another group to fluctuating UVR conditions. Despite receiving the same
dose of UVR, the first experimental generation displayed significant
treatment-by-genotype interactions with respect to survival and
reproductive output, as well as a delayed reproductive maturity under
fluctuating UVR conditions. In the following experimental generation
individuals exposed to fluctuating UVR exhibited higher fitness than those
in a constant UVR regime. The ancestral conditions, i.e, maternal
environment, however affected the survival probability and reproductive
output, but did not significantly influence the maturation date. Overall,
I demonstrate that the delivery of a stressor, not just its intensity, can
have profound fitness consequences across generations, with important
implications for seasonal succession of genotype-phenotype patterns in
natural environments.