The effects of diet on the development of Túngara frog tadpoles

The larval development of many animals can be influenced by environmental factors including water quality, temperature, food availability and diet. Altering any of these factors can either accelerate or decelerate the developmental rate and growth rate of tadpoles. In this study, we examined how differences in diet would affect túngara frog tadpoles’ growth and time to metamorphosis. Three treatments, with 12 enclosures in each, were set up for a total of 36 enclosures, each containing a single tadpole. The treatments varied in tadpoles being fed with fish flakes (high protein, low fiber), tadpole feed (low protein, high fiber), or a 1:1 combination of both. The length and body mass of the tadpoles was measured periodically before and after metamorphosis. Tadpoles raised on fish flakes metamorphosed first while tadpoles fed with tadpole feed did so last. Growth was similar in the fish flakes and the combined treatments but it was reduced in the tadpole feed treatment. In addition, deformed hind limbs were observed in the tadpole feed treatment only. The increased growth in the fish flakes treatment relative to the tadpole feed may have resulted from higher protein content (almost double) but the lack of reduced growth in the combination treatment indicates that the ideal protein content is intermediate or that other factors (such as fiber content) may have an effect. The observed differences in time to metamorphosis and growth rate demonstrate the importance of diet quality throughout larval development. Identification of the relevant differences between the diets should contribute to husbandry practices and to the current understanding of nutritional requirements of tropical frogs.