Differential effect of natural and pigment‐supplemented diets on larval development and phenotype of anurans

Diet has major effects on development, growth, health, and performance of animals. Photosynthetic pigments, in particular, are key components of the diet of many organisms that can play important roles in their development and performance. Compared to other taxa, we know relatively little about how these pigments impact amphibian larval development. We conducted diet supplementation experiments on tadpoles of two amphibian species, in which we offered various naturally co‐occurring aquatic macrophytes or diet enriched or not with supplement pigments. We evaluated the effect of these diets on developmental period, size, mass, color, and jumping performance of metamorphs exposed or not to risk of simulated pond drying during the larval period. Diet based on Myriophyllum alterniflorum resulted in high mortality rates of Mediterranean tree frog larvae ( Hyla meridionalis ), this macrophyte did not affect survival of Western spadefoot toads ( Pelobates cultripes ), but individuals took longer to reach metamorphosis. Regardless of the macrophyte consumed, spadefoot toad tadpoles speeded up metamorphosis when exposed to reduced water volume, whereas tree frog tadpoles did not show significant responses to simulated pond drying. The three supplemented diets tested—β‐carotene, lutein, and chlorophyll—had positive effects on size and mass of tree frogs; supplemented diet based on β‐carotene improved dorsal coloration of tree frogs and had positive effects on size and mass at metamorphosis of spadefoot toads. Tadpoles fed with supplements did not exhibit significant response to water reduction. Our study highlights the importance of larval diet on phenotypically plastic responses and post‐metamorphic traits in anurans.