Autopsy & forensics

Types of injuries

Forensic entomology

Editor-in-Chief: Debra L. Zynger, M.D.
Lance Van Truong, D.O.
Priya Banerjee, M.D.

Last author update: 2 February 2021
Last staff update: 2 February 2021

Copyright: 2021,, Inc.

PubMed search: Forensic entomology [TI] pathology

Lance Van Truong, D.O.
Priya Banerjee, M.D.
Page views in 2023: 421
Page views in 2024 to date: 185
Cite this page: Truong LV, Banerjee P. Forensic entomology. website. Accessed July 13th, 2024.
Definition / general
  • Forensic entomology is the study of insects / arthropods pertaining to its applications to medicolegal and criminal death investigations
  • Predictable sequence of insect colonization on a decomposing body is known as insect succession (PLoS One 2018;13:e0195785)
  • Insect succession depends on whether physical obstructions to oviposition are present and if conditions are suitable for oviposition (PLoS One 2018;13:e0195785)
  • Insect succession patterns, developmental age of immature insects and environmental data are used to estimate the postmortem interval (Forensic Sci Int 2011;211:67)
  • Blow flies are regarded as the primary and most accurate forensic indicators of time of death (J Med Entomol 1991;28:565)
  • Larval stages of flies are called maggots
  • Maggot movement through bodily fluids, especially prior to pupation, adult fly meal regurgitation and adult fly waste products may confound bloodstain pattern interpretation at the crime scene or during autopsy (Forensic Sci Int 2003;137:152)
Essential features
Antemortem insect feeding
  • Not all forensically important insects wait until death to feed (Forensic Sci Int 2004;146:S195)
    • Medical conditions and wounds can produce chemoattractants and provide substrates for necrophagous insects to feed (e.g. diabetes, ulcers, sores, wounds) (J Forensic Sci 2002;47:542)
  • Larval myiasis can be fatal (Forensic Sci Int 2004;146:S195)
    • While a low number of maggots can be used therapeutically to debride wounds, a large enough maggot mass can damage and destroy healthy tissue through buildup of larval waste products and secondary invaders in the form of predators, which may introduce harmful microorganisms into the wound site (Trends Parasitol 2001;17:176)
    • Some fly species have larva that may opportunistically switch to feeding on living tissue to overcome feeding competition within a large enough maggot mass (Forensic Sci Int 2004;146:S195)
  • Indicator of neglect or abuse
  • Complicates the use of the period of insect activity in the calculation of a postmortem interval (Forensic Sci Int 2004;146:S195)
Postmortem insect feeding
  • Insect feeding activity can modify decomposition process
    • Activity and metabolism in a maggot mass create heat (up to 25 °C above ambient air temperatures), accelerating both the decomposition process and the rate of feeding activity (J Med Entomol 1991;28:565)
    • Insect activity is temperature dependent; warmer temperatures increase rate of tissue consumption (J Med Entomol 1991;28:565)
    • Maggots release digestive enzymes, contributing to rapid localized breakdown of cadaveric tissue (Acta Trop 2013;128:686)
    • A heavy maggot load can counteract the preservative effects of refrigeration prior to autopsy; thus, a timely postmortem examination is advised (Int J Legal Med 2007;121:90)
  • Effects on skin and other soft tissue:
  • Effects on bone:
    • Beetles, moth larvae, wasps and termites can bore into bone and create microscopically visible, star shaped patterns and linear etchings, replicating the damage caused by bullets (Int J Legal Med 2019;133:307)
  • Effects on hair:
Procedural recommendations for the forensic pathologist
  • A multidisciplinary approach is recommended in death investigation; collection of insect evidence and workup is best conducted in collaboration with forensic entomology technicians or forensic entomologists (Int J Legal Med 2019;133:307)
  • In lieu of trained personnel, a thorough investigation and presentation of entomological evidence is still possible when following published guidelines
    • Best practice in forensic entomology - standards and guidelines by Amendt et al. is a resource developed by the European Association for Forensic Entomology (EAFE) for practical guidance in collection, preservation and documentation of insect evidence in medicolegal death investigations (Int J Legal Med 2007;121:90)
  • At the scene:
    • Complete photograph documentation and scene description should include body position, clothing, doors, windows and light positions to identify entry / exit points for insects and possible hiding places for pupating maggots (Int J Legal Med 2019;133:307)
    • The ambient temperature and humidity should be noted; this data is best when taken at the scene in addition to noting recent local weather station data (Int J Legal Med 2007;121:90)
    • The temperature of any maggot mass, if present, should be noted (Int J Legal Med 2007;121:90)
    • Collection of the insect evidence is best taken at the scene; always check the corpse and the surroundings for entomological evidence (Int J Legal Med 2007;121:90)
      • It is strongly recommended to collect entomological evidence from the surrounding area before the removal of the remains and under the remains immediately after removal (Int J Legal Med 2007;121:90)
      • Example sampling sites may include natural orifices, traumatic wounds, pleats of clothes, pockets, carpet and windowsills (Int J Legal Med 2007;121:90)
      • Collect living and dead specimens of every shape and size and sample flying insects, if present, with an insect net (Int J Legal Med 2007;121:90)
  • At the autopsy:
    • Inspect and sample the insects from within the body bag, clothing and body (Int J Legal Med 2007;121:90)
    • Compare clothing and position from the scene with lividity and site of injuries (Int J Legal Med 2019;133:307)
    • Sampling of suspected postmortem artifact for histological review is useful to confirm the postmortem nature of the lesion, notably the absence of congestion, inflammatory reaction and fibrin deposition (Int J Legal Med 2019;133:307)
  • Preserving insect evidence:
    • Store dead specimens immediately in 70 - 95% ethanol and avoid formalin / formaldehyde use, as insect specimens are less well preserved for morphological and molecular identification (Int J Legal Med 2007;121:90)
    • Recommended guidelines by the EAFE for storing living specimen varies by life stage and investigational goals (Int J Legal Med 2007;121:90)
      • Place eggs on moistened tissue paper within aerated vials that do not allow the escape of newly hatched larvae for transfer to an expert for rearing within 24 hours; otherwise immediate killing and preservation of all egg specimens by placing them in 70 - 95% ethanol is recommended (Int J Legal Med 2007;121:90)
      • Store larva in vials lined with coarse sawdust in a controlled humidity and temperature environment, preferably 2 - 6 °C for transfer to an expert for rearing within 24 hours; otherwise larval specimens should be quickly killed by 30 seconds of immersion in very hot but not boiling water (> 80 °C) and placed in a vial with 70 - 95% alcohol to best preserve morphological features (Int J Legal Med 2007;121:90)
      • Store pupae in vials with airflow under controlled temperatures and humidity, preferably 2 - 6 °C (Int J Legal Med 2007;121:90)
      • Preserve adults by freezing at -20 °C for 1 hour, then store in 70 - 95% alcohol or alternatively pinned to simplify identification (Int J Legal Med 2007;121:90)
      • Insect remnants, such as empty puparia and frass, can be stored under completely dry conditions in vials or in 70 - 95% ethanol (Int J Legal Med 2007;121:90)
    • EAFE standards recommends the killing of all sampled specimens when the use of insects is ambiguous at the time of collection or when rearing is impossible (Int J Legal Med 2007;121:90)
  • Submitting evidence for identification:
  • Use in toxicology workup:
    • Insect specimens may be used as a source of reliable toxicology samples in cases of severe decomposition and where conventional tissue or fluid samples are no longer available (J Forensic Leg Med 2019;67:28)
    • Chitin, the chemical which makes up the insect cuticle, accumulates and forms highly stable bonds with many drugs and toxic substances; puparial casings, which are rich in chitin, may be used in place of hair in toxicology assays in specific preparations (J Forensic Leg Med 2019;67:28)
    • Insect growth, morphology and activity can be modified by ingestion of trace amounts of drugs or toxic substances found in cadaveric tissue, complicating the calculation of the postmortem interval (J Forensic Leg Med 2019;67:28)
  • Use in identification of human DNA:
    • Mitochondrial DNA sequences have been retrieved from the dissected gut of a maggot that fed on human tissue (J Forensic Sci 2001;46:685)
Clinical images

Contributed by Priya Banerjee, M.D.
Ant feeding artifacts

Ant feeding artifacts

Ant feeding artifact along clothing

Ant feeding artifact along clothing

Beetle frass

Beetle frass

Images hosted on other servers:

Circular maggot feeding artifacts

Irregular ant feeding artifact

Board review style question #1

External examination of a decedent reveals a multifocal, orange-pink, linear lesion along the shirt collar. No petechial conjunctival hemorrhage is noted. Anterior neck dissection reveals no area of hemorrhage in the underlying soft tissue and the hyoid is intact. Microscopic examination of the lesion demonstrates absence of the epidermis without hemorrhage. What is the most likely cause of the lesion?

  1. Decomposition
  2. Excoriation
  3. Postmortem ant feeding
  4. Strangulation by shirt collar
Board review style answer #1
C. Postmortem ant feeding. Ants are known to feed along clothing lines and are generally limited to the epidermis.

Comment Here

Reference: Forensic entomology
Board review style question #2

External examination of a decedent yields the findings above. What does this artifact represent?

  1. Beetle frass
  2. Chemical burn
  3. Contact gunshot wound
  4. Electrical injury
Board review style answer #2
A. Beetle frass. Beetles typically feed late in decomposition and leave waste, called frass, which appears as whitish ribbons.

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Reference: Forensic entomology
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