Molecular identification of blowfly species (diptera: calliphoridae) and beetles (coleopterans) of forensic importance associated with pig (sus scrofa) carrion in Nigeria

Blowflies and beetles are among the invertebrate species that are attracted to dead bodies and can provide valid evidence in cases of murder or suspicious death investigation. An important consideration is the quality of the evidence which partly depends on the accurate identification of invertebrates. The morphological identification of blowflies has some limitations, especially in relation to damaged samples, or immature stages of the flies. DNA-based techniques such as the polymerase chain reaction (PCR) and sequence analysis have been applied to overcome the shortfalls of the classical identification methods. The present study combined the use of classical and PCR methods to identify invertebrates associated with pig carrions in Nigeria. Adult invertebrates were collected on and around pig carcasses in Nigeria. A total of 416 invertebrates belonging to Diptera; Calliphoridae (n = 160), Sarcophagidae (n = 26) and Muscidae (n = 72) while Coleopterans; Dermestidae (n = 52), Histeridae (n = 63), Cleridae (n = 25) and Silphidae (n = 18) families collected from pig carrions in Nigeria were identified. The cytochrome oxidase 1 ( cox1 ) gene from selected specimens was amplified and sequenced. Nucleotide sequence analysis and phylogenetic trees confirmed the presence of dipterans and coleopterans of forensic importance in Nigeria. To the best of our knowledge, this is the first report to use the mitochondrial cox1 gene coupled with sequence analysis to identify and characterize arthropods of forensic importance in Nigeria. This study provides reliable baseline data for further use in forensic entomology within the country and other regions where these arthropod species exist.