Effects of Mode of Killing on the Spatial Successional Pattern of Forensically Important Insects in Minna

Abstract

The successional pattern of insect at a cadaver is a key feature in the estimation of the minimum post-mortem interval which is the most widespread contribution of forensic entomology, the decomposition process of 12 pigs carcass (Sus scrofa L) with a mean weight of 23.24 ±1.33kg sacrificed through three methods (stabbing oxygen deprivation and zinc phosphate) were monitored throughout the rainy season of 2013/2014 and 2014/2015 seasons at Niger State College of Education (COE) and Dutsen Kura water board supply unit (DK). There was no significant difference (P>0.05) between the arrival times and duration of stay between the two study sites but there exist significant variation (P<0.05) among the methods of killings. A consistent successional pattern of insect was observed irrespective of the study site, through the consistent insect from the earliest arrival to the latest arrival for oxygen deprived and stabbed pig carcasses was Musca domestica (5.00 to 5.50 ), Lucilla sericata (41.50 to 59.00 1minutes) Chrysomya albiceps (57.50 to 73.50 minutes) C. rufaficies (59.50 to 73.00 4.24), Hermipyrellia Liqurriens (5.00 to 5.50 hours), Sarcophaga carnaria (1.00 to 2.00 days), Ophyra aenacens (3.00 days), Hermitia illucens (3.00 to 3.50 ) and coleopterans (5.50 to 6.00 days). The insect in the order calliphoridae stayed on the carcass at the range of (9.00 to 10.00 days) Muscidae (16.50 to 17.00 days) and coleopteran (22.00 to 57.50 days). The pigs sacrificed by poisoning only with witnessed the presence of musca domestica and lucilla sericata at (4.50 to 5.50 hours) and 7.00 to 7.00 hours respectively. The findings of this study suggested that the successional pattern of forensic insects in the two sites in Minna is sequence and can be used to predict post mortem interval (PMI) and can also serve as a database information for future forensic research in Niger State.