Forensic Entomology: an inventory of Arthropods collected on the decomposing pig Carrions during the dry season in Warri, Southern Nigeria

Abstract

Arthropods found on the pig carrions in the dry season in the Warri city at 05°32’34.95"N and 05°44’39.834"E from 10th December 2017 to 10th February 2018 studied. Three pigs were killed and their decomposition monitored for 60 days, arthropods were collected with the aid of sweep nets, brushes, handpicking and pitfall traps while the soil below the decaying pig carrions were searched extensively twice daily for the first week and once daily for the remaining weeks. Data analysis was done by Microsoft excel while graphs were used to demonstrate the frequencies of the arthropods in every phase of decomposition, pie chart was used to elucidate stages of putrefaction and their respective periods. The outcome of the study showed five exclusive stages of decay: fresh, bloated, active decay, advance decay and dry decay correspondingly. The fresh stage took shortest days of 2 as the dry decay took longest days of 41. A total of 1495 arthropods were collected, at the fresh stage, there were 244 arthropods, while 213 were Diptera, only 19 were Hymenoptera and 12 were also Coleoptera but at the bloated stage of decomposition, a total of 273 arthropods were recorded, Diptera were 223 as hymenoptera were 21 and Coleoptera were 29 while at the active decay stage of decomposition there were a total of 437 arthropods, 333 of them were Diptera, 29 were Hymenoptera as 75 were Coleoptera but at the advance decay stage of decomposition, there were a total of 438 arthropods, 225 of them were Diptera, 30 were Hymenoptera as 91 were Coleoptera but at the dry decay stage of decomposition, only 195 arthropods were recorded, 96 of them were Diptera, 21 were Hymenoptera and 78 were Coleoptera in that order, for the reason that the Coleoptera and Diptera used the decaying pig carrions for breeding of their offspring, they could be used in the estimation of the time after death hence are of immense forensic importance while the role of the recorded Hymenoptera could also be of great importance as the tears and wears that they created on the carrions could be cause of error in the estimation of the time of death and their predatory role could also give a fake entomofauna documentation data, more researches of this nature are to be carried out in Warri city and other neighboring communities in order to document reliable database of arthropod of forensic importance in the oil rich city.