Width as an alternative measurement to length for post-mortem interval estimations using Calliphora augur (Diptera: Calliphoridae) larvae

Abstract 

The length of fly larvae collected from corpses is often used to help provide an entomological estimate of time since death. However, ‘head-curling’ by larvae can affect the accuracy of length measurements. To investigate a possible resolution to this problem, larvae of Calliphora augur were grown on sheep's liver at two constant temperatures (20 and 25°C). Replicate samples were collected at set time intervals until pupation. Body length and width were measured for individual larvae and examined as predictors of age. It was found that body width, as measured at the junction of the fifth and sixth abdominal segments, is comparable with body length for age prediction of maggots of C. augur grown at these temperatures. Furthermore, conversion of width to length can be done with 95% accuracy from a simple linear model.

Keywords: Calliphoridae, Blowflies, Calliphora augur, Post-mortem interval, Measurement, Larvae, Forensic entomology