Data from: Do mites evolving in alternating host plants adapt to host switch?

A fluctuating environment may be perceived as a composition of different
environments, or as an environment per se, in which it is the fluctuation
itself that poses a selection pressure. If so, then organisms may adapt to
this alternation. We tested this using experimental populations of spider
mites that have been evolving for 45 generations in a homogeneous
environment (pepper or tomato plants), or in a heterogeneous environment
composed of an alternation of these two plants approximately at each
generation. The performance (daily oviposition rate and juvenile survival)
of individuals from these populations was tested in each of the
homogeneous environments, and in two alternating environments, one every
three days and the other between generations. To discriminate between
potential genetic interactions between alleles conferring adaptation to
each host plant and environmental effects of evolving in a fluctuating
environment, we compared the performance of all lines with that of a cross
between tomato and pepper lines. As a control, two lines within each
selection regime were also crossed. We found that crosses between
alternating lines and between pepper and tomato lines performed worse than
crosses between lines evolving in homogeneous environments when tested in
that environment. In contrast, alternating lines performed either better
or similarly to lines evolving in homogeneous environments when tested in
a fluctuating environment. Our results suggest that fluctuating
environments are more than the juxtaposition of two environments. Hence,
tests for adaptation of organisms evolving in such environments should be
done in fluctuating conditions.