Future Prospects 1141 Time of Death

To date, entomology still remains the most reliable method of determining the post mortem interval, however, it is anticipated that in the future volatiles associated with a decomposing body, a "chemical fingerprint", could be used to determine time of death and provide the pathologist with important forensic details (Vass et al. 2002; Statheropoulos et al. 2007). As described earlier, decomposition-related volatiles are greatly influenced by a variety of factors such as enzymatic and bacterial activity, temperature, humidity, body size, soil composition, the presence of clothing, as well as stomach content (Vass et al. 2002; Dent et al. 2004). Further investigations are required to account for such variations. Although insect development can also be affected by factors such as s temperature, humidity, and geographical location, these external influences have been studied in great detail in certain species and are thus highly predictable. Despite this, an accurate estimation of the postmortem interval still remains a difficult task (Amendt et al. 2004).

Although there are many parallels, in terms of chemical ecology-related mechanisms, between carrion flies that interact with decomposing bodies, and other insects that interact with plants, the production and release of volatile chemicals are not the same. Nevertheless, it is certain that decomposing bodies release different volatiles at different stages of decomposition. LeBlanc (2008) has found that the change in composition and concentration of volatiles released change in sync with the physical changes noted on the pig often termed Fresh, Bloated, Active Decay, Advanced Decay, and Dry stages of decomposition; therefore, giving information on the physical state of the body. Portable methods of collecting volatiles from a body have already been developed (LeBlanc 2008; Logan et al. 2009). This means that volatile samples from a decomposing body could be collected from the crime scene and analysed in order to gain added information about the stage of decay and the behaviour of the insects on the carcass. While estimating a more accurate PMI is the ultimate goal, it may also be possible to determine volatile compounds which insects have evolved to avoid, providing useful repellents (Pickett et al 1998).

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