Anonymous asked: I first thought a window for time of death could be 4-7 hours as the body is still warm (in what I assume to be 14 degree ambience) and shows only slight rigor mortis. However there are some insect eggs (I assume blowfly eggs) some of which have developed to the first instar larval stage. Surely the time of death can't be much more than 8 hours otherwise the body would be cooler and rigor mortis would be well established. Is there a fast developing Calliphora species for this?
I’m still a student so be prepared for possible inaccuracies here, but here is how I would approach this:
Have you verified that they are definitely 1st instar Calliphora larvae? This will make a difference, so best to get it checked out if not.
Different species of Calliphora show different development rates so probably best to rear them to adulthood to check with species you have and then look up the development rate for that species. There’s a nice list in this paper: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2915.2006.00600.x/full
To give an example, according to Anderson (2000), C. vicina larvae take a minimum of around 41 hours to develop to 1st instar at 15.8 degrees C +/- 0.004 degrees. So at a constant 14 degree environmental temperature, they would take longer than that.
However, the presence of certain drugs and other substances can speed up larval development, as well as factors such as higher temperatures, so it would also be necessary to make sure as far as possible that you definitely have the correct temperature.
Is there a possibility that the cadaver was colonised prior to death (myiasis)? This can happen in cases of abuse and neglect in old people and children, for example.
I don’t think any of the species I have personally worked with would develop to 1st instar in under 8 hours, but I’d advise checking that with someone with more experience if this is for something important.