Pupal age estimation of forensically important Megaselia spiracularis Schmitz (Diptera: Phoridae)

In addition to causing myiasis in humans, Megaselia spiracularis Schmitz has also been reported as a forensically important fly. The determination of a minimum post-mortem interval (PMI) often relies on the determination of the age of the larvae and pupae. The pupal stage represents about 50% of the immature development time and the pupal age may therefore serve as an important tool in entomological PMI estimation. The present study focusses on the key developmental processes during the metamorphosis of M. spiracularis pupae at different constant temperatures (21, 24, 27, 30, 33 and 36 °C). The average minimum duration of development from prepupa to adult emergence was inversely related to temperature, ranging from 177.10 ± 1.65 h at 33 °C to 379.68 ± 2.20 h at 21 °C. The pupa could not develop at 36 °C. Some morphological features that change within the puparium could be used as age markers. According to this, the pupal stage of M. spiracularis was divided into 11 stages which were fit for both sexes.