Data from: Adapting to an increasingly stressful environment: Experimental evidence for ‘micro-evolutionary priming’

In many natural systems animal populations are exposed to increasing
levels of stress. Stress levels tend to fluctuate and long-term increases
in average stress levels are often accompanied by greater amplitudes of
such fluctuations. Micro-evolutionary adaptation may allow populations to
cope with gradually increasing stress levels but may not prevent their
extirpation during acute stress events unless adaptation to low stress
levels also increases their tolerance to acute stress. We tested this
idea, here called ‘micro-evolutionary priming’, by exposing populations of
the monogonont rotifer species Brachionus calyciflorus to four
levels of copper stress (control, low, intermediate and high) during a
multigenerational selection experiment. Subsequently, in a common garden
experiment we exposed randomly selected subsets of genotypes (clones) of
each of these populations to low, intermediate and high copper levels and
assessed their population growth performance across multiple generations.
Compared to populations with an exposure history to copper, genotypes of
control populations suffered strong growth reductions when exposed to
intermediate and high levels of copper, mainly as the result of high
mortality rates. Remarkably, when exposed to low copper levels, fitness
differences between genotypes of control populations and populations
adapted to these low levels were very small, whereas the latter strongly
outperformed the first at intermediate and high copper levels. These
results highlight the potentially strong but hitherto largely ignored
impact of micro-evolutionary priming on the performance of populations in
a changing environment. We discuss potential consequences of
micro-evolutionary priming for the persistence of populations and the
spatial eco-evolutionary dynamics of metapopulations.