Data from: Genome size influences adaptive plasticity of water loss, but not metabolic rates in lungless salamanders

Many expressions of phenotype, such as physiological performance,
integrate multiple underlying traits to function. Linking component traits
to adaptive physiology thus gives insight into mechanisms of selection
acting on performance. Genome size (C-value) is a trait that influences
physiology in multiple taxa by exerting a nucleotypic effect, constraining
cell size and cellular physiology such that whole-organism mass-specific
metabolism is reduced with increasing C-value. We tested for this
mechanism of C-value function acting in lungless salamanders, plus an
unexplored potential mechanism of C-value effects constraining water
transport across the body surface to influence cutaneous water loss rates.
We found no evidence for a nucleotypic effect on metabolic rates, but we
demonstrate a relationship between C-value and water loss physiology.
Under warmer experimental conditions, C-value was inversely correlated
with water loss and positively correlated with resistance to water loss,
which demonstrated adaptive plasticity at higher temperatures. We
hypothesize this pattern results from differences in cell size
constraining diffusion and evaporation of water from the skin under warm
conditions when cutaneous perfusion is reduced. Testing this hypothesis
may confirm a previously unappreciated adaptive role for C-value variation
in this group, and reveals the possibility that genome size influences
physiological exchange across transport barriers more broadly.