EPOW Ecology Picture of the Week -- The Crime Scene Time-Keeper

Explanation: Blow flies tend to lay eggs in dead or living flesh wounds of animals ... and of people. Some species of blow flies have been implicated for spreading disease, such as limberneck that affects domestic fowl and that is caused by the bacterium Clostridium botulinum carried by some blow flies.

However, blow flies have proven to be worthy time-keepers in the context of forensic investigations. Because blow flies have a very rapid life cycle, they are used to back-date the time of death of a body in which they lay eggs, eggs pupate, and adults emerge.

This week's star helps determine time of death of a corpse during colder seasons, because this fly can withstand colder temperatures than can other blow fly species. Some sources suggest, also, that this species first inhabits a corpse two days after death, so this time needs to be added to the timing provided by its life cycle.

So here is a wonderful example of how a disease-distributing pest also serves a useful social (forensic) function!

Information:
Delhaes, L., and 8 others. 2001. Case report: recovery of Calliphora vicina first-instar larvae from a human traumatic wound associated with a progressive necrotizing bacterial infection. Am. J. Trop. Med. Hyg. 64(3-4):159-161.
Greenberg, B. 1991. Flies as forensic indicators. J. Medical Entomology 28(5):565-577.

EPOW - Ecology Picture of the Week