Impact of water temperature on larval development of the eastern tree frog (Hyla orientalis, Amphibia, Anura, Hylidae) in laboratory rearing

The eastern tree frog ( Hyla orientalis ) is declining at the northern and eastern periphery of its range. Restoration of declining amphibian populations is possible through laboratory breeding and reintroduction. This paper presents the results of a study of larval development of H. orientalis at different water temperatures. Captive-born larvae were reared in 18 individuals in containers of 39 × 28 × 28 cm filled with 18 litres of water. The rearing from the transition of the larvae to exogenous feeding until landing was carried out twice at constant water temperatures of 20°C, 23°C, 26°C, 29°C and 32°C. The juveniles of the eastern tree frog were characterized by a high survival rate (94.4-100%) under all applied temperature regimes. Higher temperatures contributed to a shorter period of larval development and a reduction in the size of juveniles after the end of metamorphosis. The authors believe that a water temperature of 26°C is the most suitable for rearing larvae of this species in artificial conditions, since under these conditions large juveniles grow in a short period of time. The results of the work can be used by conservationists, staff of breeding centers, protected areas and zoos when implementing measures to restore the numbers of H. orientalis .