Analysis of blowfly larvae growth rate in relation to larval massing across three different environmental conditions

Forensic entomology estimates the postmortem interval (PMI) in criminal investigations by analysing the larval growth rate in relation to the surrounding temperature of the crime scenes and the temperature experienced within the larval mass during the development. This relationship can be used to estimate when the dead body is initially colonised by blowfly’s larvae based on larval size and development stages. The size of larvae is commonly measured in terms of length, weight and width. The aim of this research is to investigate the relationship between surrounding temperature and larval massing temperature on the growth rate of blowflies’ larvae at three different environmental locations. The three different locations are the outdoor site, jungle site, and abandoned building site representing three different environmental conditions. In this study, three chicken carcasses, each equipped with a temperature logger, were placed in three different environmental conditions. An additional temperature logger was positioned nearby at each site to record the surrounding temperature. Three replications were incorporated to minimise the error by calculating the average value at the end of the study. Our findings indicate that each location significantly influences the surrounding temperature differently caused by natural or anthropogenic factors. The jungle site has the highest surrounding temperature recorded followed by outdoor site and abandoned building site. The larval massing temperature showed a relationship with the surrounding temperature such as jungle site with higher surrounding temperature has higher larval massing temperatures. In conclusion, the jungle site exhibited the highest growth rates of larvae in length and width due to its optimal environmental conditions, followed by outdoor site while the abandoned building site showed the lowest growth rate most likely due to suboptimal temperatures and less favourable conditions. In addition, Chrysomya megacephala and Chrysomya rufifacies were found to be pre-dominant among the larvae collected for identification. These results provide a basis for further application especially when conducting investigation involving a deceased body infested with larvae at different environmental locations. These findings can enhance the accuracy of PMI estimations, improving the reliability of forensic analysis and entomology. Future studies should include more environmental variables, such as humidity, and larger carcass models to better understand the influence of carcass size on larval growth rates.