Development of Piophila megastigmata (Diptera: Piophilida) at seven constant temperatures

In forensic entomology, the time-related growth and development of carrion insects allows for the estimation of the minimum postmortem interval (PMI_min). Piophila megastigmata (Diptera: Piophilidae) is of great significance in estimating PMI_min in the late stage of corpse decay. In this paper, the development of P. megastigmata was investigated under the seven constant temperatures of 16-34 °C. The total development time at each temperature was 970.38, 824.50, 593.13, 498.25, 392.00, 385.63 and 405.87 h, respectively. The isomorphen diagram shows the trend of development during different developmental stages at different temperatures. By using a revised linear regression model, the estimated lower lethal developmental thresholds (T_L) and thermal summation constant (K) were found to be 10.57 °C and 6936.78 degree hours, respectively. According to a nonlinear model, the T_L, upper lethal developmental thresholds (T_H), and intrinsic optimum temperature (T_Φ) were determined to be 7.53, 34.68, and20.43 °C, respectively. Also, logistic function and an isomegalen diagram were constructed according to the continuous changes in larval body length, and illustrates the time required to develop to a certain length at different temperatures. The obtained results offer crucial fundamental developmental information regarding P. megastigmata, which can be applied in PMI_min estimation.