Temperature constrains diet-induced plasticity in the life-history of an aquatic vertebrate

An experimental study investigating how diet influences the effects of temperature on the life-history of the spiny toad (Bufo spinosus). Warming accelerated larval development and growth while reducing body mass and body condition. Tadpoles fed selectively and assimilated proportionally fewer animal-based resources at warmer temperatures. This behavioural flexibility maintained body length but only partially compensated for the detrimental effects of warming, while shifting body composition by increasing tissue C:N ratio. The nutritional advantages of an animal-based diet observed at low temperature largely disappeared under warmer conditions, demonstrating that increasing temperature constrained diet-induced plasticity across multiple life-history traits. These findings provide experimental evidence that warming canalises life-history trajectories by limiting the capacity of diet to reshape the phenotypic architecture of a vertebrate ectotherm. They suggest that selective feeding can buffer warming effects only within a limited thermal window, beyond which amphibians and other ectotherms may become increasingly vulnerable to climate warming.