Effect of temperature on incubation period, hatching rate, and larvae deformity in Severum Heros severus

This study was aimed to determine the optimum temperature, as one of the most important factors in hatching success during incubation time in Severum Heros severus. For this purpose, six thermal treatments, including 24, 26, 28, 30, 32 and 34°C were opted, and each treatment was performed with three replications. After incubation period, four hatching success indices, including incubation period, survival rate, hatching rate and deformed larvae were estimated. The results indicated that the optimum temperature for Severum’s eggs incubation is 28°C. A short incubation period, along with significant decreasing in mortality rate and deformed larvae and high hatching rate were observed in the optimum temperature. The highest hatching rate (94.9±1.4%) and the lowest deformed larvae (0.2%) were observed in 28°C (P<0.05). In the 32°C the eggs were hatched within the shortest period with 79.6±3.1 h, that was significant shorter than others (P<0.05). The results showed that lower or higher temperatures than the optimum, causes an increasing in mortality rate, which the 24°C and 34°C caused a complete loss of eggs.