Identification of Diptera Puparia in Forensic and Archeo-Funerary Contexts.

Simple Summary: In forensic entomology, insects are used to estimate the time since death and to answer other investigative questions, such as determining if the body was moved postmortem or identifying the season of death. In funerary archeoentomology, insects provide information related to the season of death, body transfer, and funerary practices. To obtain this information, the correct identification of specimens collected from the scene is fundamental. In old cases and archeological contexts, the majority of entomological evidence samples found are fly puparia, barrel-like structures formed from the third-instar larval cuticle where metamorphosis takes place. Despite recent publications of identification keys for certain fly larvae and adults, there is still a lack of tools for puparium identification. This problem is exacerbated by the scarcity of diagnostic features present on the puparia. This paper critically reviews the techniques available for puparium identification in addition to traditional morphological analysis. It describes DNA-based approaches and chemical analyses of cuticular lipids and hydrocarbons, highlighting the importance of using non-invasive methods to guarantee the repeatability of the analysis—a key element in forensic science—or to preserve precious and unique specimens from museum collections. 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. [ABSTRACT FROM AUTHOR]