Time and energy costs of metamorphosis in the Indian bullfrog Rana tigrina

Abstract

Ran tigirina tadpoles were reared on different foods and rations at diffrent temperatures and larval densities in waters of diffrent qualities and at different aquarium water depths. Time and energy costs of metamorphosis were estimated. With the exception of temperature, none of these factors affect the duration of the metamorphic period, although they influence larval duration. They affects energy density of the frog at the initiation and termination of metamorphosis. Ration, larval density and food quality alter the energy density of the tadpole at climax. The metamorphic events results in loss of tadpole energy and depletion of energy density. Accumulation of 1,500 J by the terminal tadpole is the minimum required energy for successful metamorphosis. A greater accumulation of body (size) energy in the terminal tadminal tadpole is advantageous, as it enhances metamorphic efficiency and reduces metamorphic metabolic rate. High metabolic rate during the larval period is associated with low metabolic rate during the metamorphic period. Metamorphic metabolic rate and energy content of the freshly emerged froglet can be predicted from that of the terminal larva.