Retrospective review of forensic entomology casework in eastern Australia from 1994 to 2022

Forensic entomology can be a crucial source of information for medicolegal investigations, with its most well-known application being for estimating minimum post-mortem interval (mPMI) in death investigations. The analysis of entomological evidence requires robust data on insect ecology, life history, behaviour, and taxonomy. In Australia, substantial basic research on forensically relevant insects has focused predominately in the populous southeast and southwest; however, knowledge gaps remain, most importantly for the tropical north. In addition, there are scant casework data available publicly, which limits the ability of practitioners to make connections between fundamental research and real-world casework and hampers refinement of analytical methods and techniques. To address this gap, this project collated and analysed data from expert forensic entomological casework reports for five eastern Australia jurisdictions (South Australia, Victoria, New South Wales, Australian Capital Territory and Queensland) for a period spanning nearly thirty years (1994-2022). Relevant data extracted from casework reports included species and life stages collected, various decedent and case characteristics, type of opinion requested and estimated mPMI. These data were used to explore associations between species composition and geographical region, surrounding environment, season, and decedent characteristics (e.g., wounds). Additionally, the accuracy and investigative 'value' of mPMI estimates was assessed, which demonstrated that entomology-derived timeframes are largely reliable and highly informative. Finally, we report the first records in Australian casework for several species and highlight several areas that require additional research to fill critical gaps in our knowledge. Overall, this review represents highly practical real-world data that will be of enduring benefit to the forensic community.