From the Micro to the Macro – Now the Big Guys Move In

Abstract

Which insects are present on a human corpse has been of great interest to detectives and pathologists for many years because it helps them to establish the time of death of a deceased person. One of the earliest researchers in this area (a subject that is part of the wider field of “Forensic Entomology” – Box 6.1) was Jean Pierre Mégnin (1828–1905), a French veterinarian and entomologist. He published many articles and books on his research, especially on the succession of insects that occurs on corpses. One of the main conclusions from his research was that unburied corpses experienced eight waves of insect succession. This illustrates nicely what we’d expect following our studies of corpse microbiology – the environment of the corpse is largely responsible for dictating which insects can live there. In other words, the timing of the appearance of different insects on a corpse is another example of ecological succession. But how do insects know when a corpse is suitable for them? This is largely due to their ability to detect particular chemicals produced by the corpse at the different stages of decomposition. When the corpse is above ground, its appearance and colour are additional indications of its suitability for colonisation by a particular type of insect.