All you CSI folk – YOU’RE GETTING IT WRONG!
Collecting insects from dead bodies is a staple of crime shows. CSI Posers also carefully note the internal temperature of the recently expired. Why do they do that?
Blow flies lay eggs within a minute of death, summoned by chemicals with the fabulous names of putrescine and cadaverine. The age of a maggot predicts the time someone began their dirt nap. Elaborate mathematical formulas* are used for calculating maggot age. Plug in the size of the maggots, body temperature, and environmental temperature, and Voila! Estimated PMI, or Post-Mortem Interval.
Just one small problem in this nice, neat methodology. Maggots generate heat as they consume a body. They generate enough heat that there are multiple cases of maggots continuing to develop in refrigerated morgues.
However, the forensic equations used to calculate time of death don’t factor in maggot heat, which could be a problem for accurately estimating PMI. Knowing when someone actually died is kind of critical in crime investigations. A recently published paper attempted to quantify just how hot a bunch of maggots can get:
Quantifying the Temperature of Maggot Masses and its Relationship to Decomposition. Heaton et al. J Forensic Sci. 2014 doi: 10.1111/1556-4029.12396.