Data from: Distinct cold tolerance traits independently vary across genotypes in Drosophila melanogaster

The ability to cope with low temperature is a critical adaptation in
thermally variable environments. Cold hardiness is comprised of several
traits, including minimum temperatures for growth and activity, ability to
survive severe cold, and ability to recover normal function after cold
subsides. Across species, these traits are correlated and share
physiological mechanisms, suggesting they were shaped by shared
evolutionary processes. However, the extent cold hardiness traits and
their associated mechanisms covary within populations has not been
assessed. We measured five cold hardiness traits – critical thermal
minimum (CTmin), chill coma recovery (CCR), acute and chronic cold
tolerance, and cold-induced changes in locomotor behavior – along with
cold-induced expression of two genes with known roles in cold hardiness
(Heat Shock Protein 70 and Frost) – across 12 lines of D. melanogaster
derived from a single population. We observed significant genetic
variation in all traits, but few correlated across genotypes, and these
correlations were sex-dependent. Further, cold-induced gene expression
varied by genotype, but there was no evidence supporting our hypothesis
that cold-hardy lines would have either higher baseline expression or
induction of stress genes. These results suggest cold hardiness traits
possess unique mechanisms and may have the capacity to evolve
independently.