Forensic entomology is one of the most important branches of forensic sciences that contributes significantly to solving criminal cases. It is based on studying insects associated with decomposing bodies and identifying their succession patterns. Since insect colonization follows a predictable timeline, investigators can use it to estimate the post-mortem interval (PMI) and reconstruct the circumstances of death.<br /><br /><br />---<br /><br />I. Stages of Body Decomposition<br /><br />After death, the human body undergoes several decomposition stages, the speed of which depends on environmental factors such as temperature, humidity, and soil type. The main stages are:<br /><br />1. Fresh Stage<br /><br />Begins immediately after death.<br /><br />Features: cessation of circulation and respiration, rigor mortis, skin pallor.<br /><br />Internal bacteria start releasing gases, leading to bloating.<br /><br /><br /><br />2. Bloating Stage<br /><br />Accumulation of gases inside the body.<br /><br />Foul odors emerge.<br /><br />Fluids begin leaking from natural openings.<br /><br /><br /><br />3. Active Decay Stage<br /><br />Tissue breakdown intensifies, and skin ruptures.<br /><br />Strong release of decomposition fluids into the environment.<br /><br />Peak insect activity occurs.<br /><br /><br /><br />4. Advanced Decay Stage<br /><br />Reduced odor compared to earlier stages.<br /><br />Remaining dried tissues and cartilage.<br /><br />Noticeable decline in insect abundance.<br /><br /><br /><br />5. Dry or Remains Stage<br /><br />Only bones, hair, and dry tissues remain.<br /><br />Minimal odor.<br /><br />Very few insects present.<br /><br /><br /><br /><br /><br />---<br /><br />II. Insects Associated with Decomposition Stages<br /><br />1. Fresh and Bloating Stages<br /><br />Blowflies (Calliphoridae).<br /><br />Green bottle flies.<br /><br />These species arrive quickly to oviposit around body openings.<br /><br /><br /><br />2. Active Decay Stage<br /><br />Maggots (larvae of blowflies and other dipterans).<br /><br />Carrion beetles (Silphidae).<br /><br /><br /><br />3. Advanced Decay Stage<br /><br />Dermestid beetles.<br /><br />Spiders and mites feeding on insect remains.<br /><br /><br /><br />4. Dry Stage<br /><br />Bone beetles (Trogidae).<br /><br />Moths and mites feeding on hair and dried skin.<br /><br /><br /><br /><br /><br />---<br /><br />III. Forensic Importance<br /><br />Estimating Time of Death (PMI): Insect succession provides a more precise timeline than decomposition alone.<br /><br />Locating the Death Site: Some insects are habitat-specific (rural vs. urban).<br /><br />Detecting Body Relocation: The presence of insects inconsistent with the discovery site can indicate movement of the body.<br /><br />Toxicological Evidence: Larvae can reveal drugs or toxins ingested before death.<br /><br /><br /><br />---<br /><br />Conclusion<br /><br />The study of body decomposition stages and associated insects is a vital forensic tool. Insects act as “small investigators,” offering crucial evidence that assists forensic scientists and legal authorities in solving complex cases. Their predictable life cycles and ecological roles make them indispensable in reconstructing timelines and circumstances of death<br /><br /><br />Al-Mustaqbal University – the first university in Iraq.<br/><br/><a href=https://www.un.org/sustainabledevelopment/ar/education/ target=_blank>Goal 4</a>