Haemorrhagic Artefacts Produced by Ant Activity on Human Cadavers in the Early Post-Mortem Period

Abstract

Forensic entomology is primarily focused on using carrion blow flies and beetles (Diptera and Coleoptera) to estimate the time since death. However, insect artefacts, such as footprints, defecations, regurgitations, and splatters are also considered within the disciplines of bloodstain pattern analysis (BPA), and ants (Hymenoptera: Formicidae) have been studied in forensic pathology for their potential to alter bodies. Although ant activity has been mostly reported as “dry marks” (abrasions) on decomposing bodies, their colonisation of congested or hypostatic anatomical regions can produce alterations that mimic active or recent haemorrhages. Therefore, if a body exhibits external haemorrhage/s without any apparent origin, artefacts caused by insects, such as ants, should be considered. This study describes ten cases of post-mortem ant activity observed in the Andaman and Nicobar Islands (India), and analyses the resulting external haemorrhagic artefacts, which exhibit different patterns of morphology, distribution, and location. The study proposes a classification system to aid in identifying bloodstain patterns caused by ant activity, assisting in determining the mechanism/s of the lesions, the original position of the body, and any subsequent interactions with the surrounding environment. Ultimately, this classification can improve the accuracy of reconstructing the events that occurred during the early post-mortem period, as well as the circumstances surrounding death.

Ant bite artifacts in a case of hanging

“…Multiple components contribute to the general appearance of these artifacts. The fundamental physical characteristics of blood, such as its viscosity, surface tension, and ability of blood to coagulate, play a crucial part in the formation of the postmortem bleeding artifacts [4]. In addition, the size and depth of punctures caused by ant mandibles differ depending on the type of ant that bit and the force with which the bite was distributed [8].…”

“…The literature suggests that for droplets to maintain their shape, they should be exposed to the outer environment and need to be formed on a flat surface parallel to the ground. A droplet pattern can be produced depending on the final position of the body, which may include sitting, stooping, kneeling, or lying, provided that the individual is clothing‐free, flat, and parallel to the ground [4]. In this case, the deceased was found partially hanged in between stooping to kneeling position in which the lower part of the leg and ankle, where most of the droplet lesions were located, were almost parallel to the ground.…”

“…Stripe patterns can also be caused by the breakage of droplet tension [9]. Stripe patterns have been reported in hanging cases over the areas of the genital region and lower limbs [4]. In this case, the stripe pattern was mostly present on the front of the leg on the upper part and over the lateral aspect and back of the leg as these parts became oblique to the ground in between stooping to kneeling position, enabling the blood to travel in a stripe pattern.…”

“…However, in the congested body regions and areas of hypostasis, postmortem bleeding lesions have been documented [3,4]. This type of postmortem bleeding artifact is less frequent as compared to non-bleeding type [4]. Four types of postmortem bleeding artifact patterns due to ant bites have been documented in the literature: droplet pattern, stripe pattern, pool pattern, and mixed pattern [4].…”

“…This type of postmortem bleeding artifact is less frequent as compared to non‐bleeding type [4]. Four types of postmortem bleeding artifact patterns due to ant bites have been documented in the literature: droplet pattern, stripe pattern, pool pattern, and mixed pattern [4]. This case reports the mixed pattern (droplet pattern and strip pattern) of postmortem bleeding artifacts along with usual excoriated lesions due to ant bites in a hanging case.…”