The utility of coleoptera in forensic investigations

Abstract

Forensic entomology is a developing field of forensic science, so there are many avenues to investigate. These avenues include novel directions that have never been addressed, as well as more critical and rigorous research into areas which have already been explored. Most research in forensic entomology has focused on flies, and beetles (Coleoptera) have been at best under-emphasized. A good example of this is the review by Smith (1986), where 70 pages are dedicated to Diptera and only 12 to Coleoptera; this situation has changed little in the subsequent 20 years. To contextualize the neglect, throughout the world there are at least as many species of Coleoptera that may visit a particular carcass as Diptera (Braack 1986; Louw and van der Linde 1993; Bourel et al. 1999; Lopes de Carvalho et al. 2000; Pérez et al. 2005; Shea 2005; Watson and Carlton 2005a; Salazar 2006; Martinez et al. 2007). A common assumption underlying the neglect of Coleoptera is that Diptera locate corpses faster, and thus give a more accurate estimate of minimum Post Mortem Interval (PMImin). Recent observations (Midgley and Villet 2009b) have shown that Thanatophilus micans (Silphidae) can locate corpses and start breeding within 24 h of death, and thus the potential utility of estimates based on this species is equal to that of those based on flies. Beetles form a taxonomically and ecologically diverse part of the carrion insect community (Smith 1986; Braack 1986; Bourel et al. 1999; Shea 2005; Tabor et al. 2004; Watson and Carlton 2005a; Salazar 2006), thus providing a wide spectrum of sources of potential evidence. They are also integral to postmortem biology. For instance, larder beetles can, given ideal conditions of desiccation or even mummification, accelerate the decomposition of a corpse (Schrder et al. 2002), and produce characteristic postmortem changes (Voight 1965) that should be distinguished from antemortem trauma. They also complicate other forensic analyses (e.g. Offelle et al. 2007). This chapter aims to highlight potential uses of beetles in forensic entomology and review the relevant literature.