Forensic and ecological perspectives on insect succession on vertebrate remains

Entomological evidence is commonly used to estimate a post-mortem interval (PMI) in medicolegal investigations of deceased individuals. A PMI from insect-derived data can be estimated by either examining the thermal development rates of larvae or analysing the carrion insect succession process. The larval development method is well-established and reliable, while the succession method is less reliable as it depends on the predictable sequences of species arriving at a cadaver, which is a highly variable process. The effect of abiotic factors such as temperature and season on succession have been well documented, however the role of biotic factors has received far less attention. For the succession method to be reliably applied to forensic casework, a complete knowledge of all factors driving successional changes in insect communities needs to be known to identify and understand sources of variation. Parallel to developments in forensic science, carrion ecologists have begun to quantify the biological sources of variation in carrion insect succession and identify the role carrion plays in ecosystem function. Importantly, the carrion resource and associated necrobiome have been identified as important ecological drivers of variation in carrion insect succession. Yet these ecological approaches and techniques have yet to be transferred to forensic entomology. For example, pigs are often used as substitutes for human cadavers in forensic entomology despite the relatively unknown effect of cadaver type on carrion insect succession. There is great potential, therefore, to examine how developments in ecology might be used to advance forensic entomology. This thesis aims to learn from carrion ecology to advance forensic entomology by exploring ecological perspectives on how biotic factors such as cadaver type, carrion resource and species interactions drive variation in carrion insect succession. To do this, I conducted an innovative, multi-season experiment using pig and human cadavers at the Australian Facility for Taphonomic Experimental Research (AFTER).