Data from: Variation in developmental temperature alters adulthood plasticity of thermal tolerance in Tigriopus californicus

In response to environmental change, organisms rely on both genetic
adaptation and phenotypic plasticity to adjust key traits that are
necessary for survival and reproduction. Given the accelerating rate of
climate change, plasticity may be particularly important. For organisms in
warming aquatic habitats, upper thermal tolerance is likely to be a key
trait, and many organisms express plasticity in this trait in response to
developmental or adulthood temperatures. Although plasticity at one life
stage may influence plasticity at another life stage, relatively little is
known about this possibility for thermal tolerance. Here we used locally
adapted populations of the copepod Tigriopus californicus to investigate
these potential effects in an intertidal ectotherm. We found that low
latitude populations had greater critical thermal maxima (CTmax) than high
latitude populations, and variation in developmental temperature altered
CTmax plasticity in adults. After development at 25°C, CTmax was plastic
in adults, whereas no adulthood plasticity in this trait was observed
after development at 20°C. This pattern was identical across four
populations, suggesting that local thermal adaptation has not shaped this
effect among these populations. Differences in the capacities to maintain
ATP synthesis rates and to induce heat shock proteins at high
temperatures, two likely mechanisms of local adaptation in this species,
were consistent with changes in CTmax due to phenotypic plasticity, which
suggests that there is likely mechanistic overlap between the effects of
plasticity and adaptation. Together, these results indicate that
developmental effects may have substantial impacts on upper thermal
tolerance plasticity in adult ectotherms.