Negative relationship between thermal tolerance and plasticity in tolerance emerges during experimental evolution in a widespread marine invertebrate

Whether populations can adapt to predicted climate change conditions, and
how rapidly, are critical questions for the management of natural systems.
Experimental evolution has become an important tool to answer these
questions. In order to provide useful, realistic insights into the
adaptive response of populations to climate change, there needs to be
careful consideration of how genetic differentiation and phenotypic
plasticity interact to generate observed phenotypic changes. We
exposed three populations of the widespread
copepod Acartia tonsa (Crustacea) to chronic, sub-lethal
temperature selection for 15 generations. We generated thermal
survivorship curves at regular intervals both during and after this period
of selection to track the evolution of thermal tolerance. Using reciprocal
transplants between ambient and warming conditions, we also tracked
changes in the strength of phenotypic plasticity in thermal tolerance. We
observed significant increases in thermal tolerance in the warming
lineages, while plasticity in thermal tolerance was strongly
reduced.