Impact of Temperature on Larval Development of the Green Toad (Bufotes Viridis, Amphibia, Anura, Bufonidae) in Captivity

Abstract

Identification of optimal temperature regimes to obtain the best values of productive indicators (reduction of development duration and feed costs, increase in size and survival rate) is the most crucial task for the development of amphibian breeding technologies. The paper presents the results of a study of the effect of temperature on the larval development of the green toad (Bufotes viridis). The offspring of a pair of green toads caught in the Kaluga region (Russia) served as the material for the work. Spawning was stimulated by injections of surfagon. During the transition of larvae to exogenous feeding, 144 individuals were selected from them for further growing. For experiments, containers measuring 39 × 28 × 28 cm filled with 18 liters of water were used. The animals were grown at a density of one larva per liter of water at the following temperatures: 20°C, 23°C, 26°C and 29°C. The larvae were fed daily with “TetraMin Flakes”. When the forelimbs appeared and when emerging from the water, the body length was measured in young toads. It is noted that with all temperature regimes (from 23°C to 29°C), the green toad larvae grew and metamorphosed successfully. Increasing temperature reduces the duration of larval development, but does not affect the size of the young emerging from the water. However, decreases in temperature below 23°C and increases above 26°C contribute to a decrease in survival. Based on the aforesaid, it is recommended that green toad larvae should be grown at 23–26°C to produce juveniles with body lengths of 11.20–20.83 mm and survival rates of 94–100% in 28–59 days.