Identification of Diptera Puparia in Forensic and Archeo-Funerary Contexts

Abstract

Diptera identification is fundamental in forensic entomology as well as in funerary archeoentomology, where the challenge is exacerbated by the presence of immature stages such as larvae and puparia. In these two developmental stages, specimens possess a very limited number of diagnostic features, and for puparia, there is also a lack of identification tools such as descriptions and identification keys. Morphological analysis, DNA-based techniques, and cuticular chemical analyses all show good potential for species identification; however, they also have some limitations. DNA-based identification is primarily hindered by the incompleteness of genetic databases and the presence of PCR inhibitors often co-extracted from the puparial cuticle. Chemical analysis of the cuticle is showing promising results, but this approach is also limited by the insufficient profile database and requires specific, expensive equipment, as well as trained personnel. Additionally, to ensure the repeatability of the analysis-a critical aspect in forensic investigations-and to preserve precious and unique specimens from museum collections, non-invasive protocols and techniques must be prioritized for species identification.

Keywords: Diptera; bioarcheology; cuticular hydrocarbons; cuticular lipids; forensic entomology; molecular identification; puparia; species identification; zooarcheology.

Figure 1

Schematic representation of the trend in the number of larvae (dashed line) and puparia (continuous line) since the time of colonization. The slow decrease in the number of puparia with time is related to predation, dispersion, and taphonomic processes.

Figure 2

Diagnostic characteristics of Diptera puparia. Ventral views and anatomical details of a puparium analyzed for the diagnosis of the species are schematically shown. Each element is reliably reproduced from photographs; however, the whole representation is not realistic as the elements are not in scale and have been selected from multiple species.