Data from: Are acute and acclimated thermal effects on metabolic rate modulated by cell size? A comparison between diploid and triploid zebrafish larvae

Being composed of small cells may carry energetic costs related to
maintaining ionic gradients across cell membranes as well as benefits
related to diffusive oxygen uptake. Here we test the hypothesis that these
costs and benefits of cell size in ectotherms are temperature dependent.
To study the consequences of cell size for whole-organism metabolic rate
we compared diploid and triploid zebrafish larvae differing in cell size.
A fully factorial design was applied combining three different rearing and
test temperatures that allowed us to distinguish acute from acclimated
thermal effects. Individual oxygen consumption rates of diploid and
triploid larvae across declining levels of oxygen availability were
measured. We found that both acute and acclimated thermal effects affected
the metabolic response. In comparison to triploids, diploids responded
more strongly to acute temperatures, especially when reared at the highest
temperature. These observations support the hypothesis that animals
composed of smaller cells (i.e. diploids) are less vulnerable to oxygen
limitation in warm aquatic habitats. Furthermore, we found slightly
improved hypoxia tolerance in diploids. By contrast, warm-reared triploids
had higher metabolic rates when they were tested at acute cold
temperature, suggesting that being composed of larger cells may provide
metabolic advantages in the cold. We offer two mechanisms as a potential
explanation of this result, related to homeoviscous adaptation of membrane
function and the mitigation of developmental noise. Our results suggest
that being composed of larger cells provides metabolic advantages in cold
water, while being composed of smaller cells provides metabolic advantages
in warm water.