Obun Cletus, Onyejike Darlington Nnamdi, Esomonu Ugochukwu Godfrey, Egwu Ogugua Augustine, Dimkpa Chiwendu Modesta
Department of Anatomy and Forensic Anthropology, Faculty of Basic Medical Sciences, University of Cross River, Okuku, Nigeria.
Department of Forensic Medicine, School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa.
J Forensic Sci. 2025 Jul;70(4):1603-1608. doi: 10.1111/1556-4029.70067. Epub 2025 May 25.
The rising homicide rates in Nigeria underscore the necessity for comprehensive post-mortem interval (PMI) estimations to enhance the reliability of forensic investigations. This study investigates the impact of Marabunta ants (Hymenoptera: Formicidae) on the decomposition process and PMI estimation in pig carcasses during the wet season in Okuku, Nigeria. Using two juvenile domestic pigs, we employed a controlled experimental approach at the Department of Anatomy and Forensic Anthropology Research Facility. The study spanned 30 days, with systematic observations of postmortem changes, insect activity and environmental conditions recorded at specified intervals. Results indicated pronounced effects of Marabunta ants on decomposition dynamics. Notably, the presence of these ants altered the expected insect succession patterns, delaying the colonisation by blowflies, which typically dominate the initial decay stages. By the second day, marked ant activity was observed, leading to distinct bite marks on the carcasses, while the other carcasses exhibited standard decomposition without any interference. Accumulated degree days (ADD) and total body scores (TBS) demonstrated a parabolic relationship, revealing rapid initial decay followed by a stabilisation phase as skeletonisation progressed. This research confirms that environmental conditions and insect activities significantly influence decomposition rates and PMI estimations. The findings suggest a need for forensic practitioners to recognise the role of Marabunta ants in decay processes and the potential misinterpretations of ant-induced marks as perimortem injuries. Future studies should explore seasonal variations in decomposition and insect succession to refine forensic entomological methodologies.
尼日利亚不断上升的凶杀率凸显了进行全面的死后间隔时间（PMI）估计以提高法医调查可靠性的必要性。本研究调查了在尼日利亚奥库库的雨季，行军蚁（膜翅目：蚁科）对猪尸体分解过程和PMI估计的影响。我们在解剖学和法医人类学研究设施使用了两只幼年家猪，采用了对照实验方法。该研究持续了30天，在特定间隔对死后变化、昆虫活动和环境条件进行了系统观察。结果表明行军蚁对分解动态有显著影响。值得注意的是，这些蚂蚁的存在改变了预期的昆虫演替模式，延迟了通常在初始腐烂阶段占主导的丽蝇的定殖。到第二天，观察到明显的蚂蚁活动，导致尸体上有明显的咬痕，而其他尸体则呈现出没有任何干扰的标准分解状态。累积度日（ADD）和总体评分（TBS）呈现出抛物线关系，表明随着骨骼化的进展，最初腐烂迅速，随后进入稳定阶段。本研究证实环境条件和昆虫活动会显著影响分解速率和PMI估计。研究结果表明，法医从业者需要认识到行军蚁在腐烂过程中的作用，以及将蚂蚁造成的痕迹误判为生前损伤的可能性。未来的研究应探索分解和昆虫演替的季节性变化，以完善法医昆虫学方法。
