Postmortem interval estimation based on the thermal developmental patterns of Protophormia terraenovae...

Protophormia terraenovae (Robineau-Desvoidy, 1830) is a Calliphorid fly that is widely distributed throughout the Holarctic region with strong adaptability to cold and high-altitude environments. As a common sanitary pest, it is capable of transmitting a variety of pathogens and is one of the species of concern in public health. However, due to its cold-adaptability, it has become an ideal species for estimating the minimum postmortem interval (PMImin) in forensic entomology. Given that there may be developmental differences among P. terraenovae populations in different regions and that the developmental model of this species is still incomplete, this study investigated the developmental patterns of P. terraenovae populations in Northwest China under seven different constant temperature conditions ranging from 16 to 34 °C. Results showed that within the temperature range of 16 to 34 °C, the egg-to-adult development duration of P. terraenovae ranged from a maximum of 713.50 ± 1.1 h at 16 °C to a minimum of 233.25 ± 1.4 h at 34 °C. Based on the developmental events, accumulated degree-hours, and developmental rates of P. terraenovae at these different temperatures, an isomorphen diagram, linear thermal summation models, and nonlinear thermodynamic Optimal SSI models were constructed. Additionally, a revised logistic model was employed to fit the changes in larval length over developmental time at different temperatures, and based on the data generated by the logistic model, an isomegalen diagram model was established. The findings of this study provide a reliable scientific basis for estimating PMImin using P. terraenovae in forensic cases.