Effects Of Dietary Protein Variations At Different Life-Stages On Vocal Dominance Of The African Clawed Frogs

How nutritional conditions during early development affect an organism's phenotype at adulthood is still poorly understood despite a plethora of research on developmental plasticity. The "environmental matching" hypothesis predicts that individuals will have high fitness providing that their adult environment "matches" what they experienced during development. In contrast. the "silver spoon" hypothesis predicts that individuals who obtain better developmental resources will be generally superior. Here we tested these two hypotheses and examined the underlying hormonal mechanisms by manipulating the early dietary protein content of African clawed frogs (Xenopus laevis) for a year with a 2x2 factorial experimental design. We found that only a low-protein food during development enhanced the vocal competition ability of male X. laevis, and that vocal dominance was associated with higher cortisol levels but not related with testosterone content. These results were not congruent with the "environmental matching' hypothesis or with the "silver spoon" hypothesis, suggesting the behavioral plasticity during development is more complex than our expectation in amphibians.