Seasonal Time Delays in Fly Oviposition is Genuinely a “Period of Concern”: Pioneer Prototype Human Body Farm Study in India

In medico-legal forensic entomology, the minimum postmortem interval (PMI) is calculated from the development of fly larvae on cadavers. However, the time lapse from natural exposure to egg laying (oviposition), referred to as the pre-oviposition period (POP), is often overlooked. The present study highlights the seasonal variation in POP in the hot and humid tropical climatic conditions of Kolkata, West Bengal, India. In this study, a prototype human body farm set-up (crime scene [CS]) was prepared with unclaimed human body remains. A total of 33 sets of experiments were done with neonatal remains and amputated body parts. For each set of experiment the site was observed once a day at a fixed time to record the day and time of oviposition. The ambient temperature and relative humidity in CS were recorded using an electronic temperature–humidity logger. The maximum POP was recorded in the winter season (80.8 hours) and the minimum in summer (20 hours). In winter, with every drop in ambient temperature, POP increases. This track of POP is extremely important in the context of total PMI estimation through entomological evidence. The data presented in this work is the first of its kind generated from a “body farm” study in India. The generated data could be used as a standard for PMI estimation from outdoor decomposition of human remains in the climatic conditions of the tropical regions of the world.