Studying Ant Bites on Cadavers May Advance Criminal Investigations
by Douglas Ankney
Forensic entomology generally focuses on the activity of blowflies and beetles in estimating the time of death. But Professor Paola Magni of Australia’s Murdoch University is a leading forensic entomologist urging forensic professionals to consider the activity of other insects, including ants.
Magni is the lead author of a new study appearing in Forensic Sciences that examined 10 real cases of ant activity on cadavers during the early postmortem period. The deaths occurred between 2015 and 2021 in the Andaman and Nicobar Islands, Union Territory, India. The cases had an estimated postmortem interval of between four hours and one day.
The study proposed a classification system of four categories that would assist in identifying, inter alia, the position of the body at the time of death and whether the body was moved postmortem. The four categories are:
(1) Droplet Pattern—According to the study, “blood droplets can result from the abrasions of ant mandibles on the skin or mucosal surfaces of a cadaver.” Droplets maintain their shape by forming “on a flat surface parallel to the ground and exposed to the air. Therefore, the presence of droplets suggests the body position has remained undisturbed since the insect activity, providing a stable flat surface for the formation and maintenance of such patterns.”
(2) Stripe Pattern—“Stripe patterns are common in hanging cadavers, and can be found with a mixed pattern of droplets.” Observation of the shape and distribution of the stripe pattern aids in determining the position of the body at the time of death. Examiners must account for the initial location of the ant bites and the possibility of clothing or other items affecting the stripe pattern.
(3) Pool Pattern—“When ants are active in a confined area of the body, they may produce a large number of blood droplets that merge into small pools or large blood stains.” Pool-pattern analysis considers multiple factors. The shape, diameter, and depth of blood in the pool—along with the texture and the porosity of the surface on which the pool formed—aids in determining the timing of the hemorrhage and provides insights into the time of death and the posture of the body in relation to the surface.
(4) Mixed Pattern—“[A] mixed pattern exhibits characteristics of two or more of the other bloodstain patterns, and can occur when the crime/death scene was highly dynamic—such as a struggle or altercation or the body was moved postmortem, for example, by first responders.” Mixed patterns often develop “as a consequence of natural events and on the posterior regions of bodies due to nonstandard recovery procedures.”
The authors of the study believe this area of research “is ongoing due to the changing nature of ants and insects as invasive species continue to make their impact across the world.” Magni said: “We continue to learn more about the impact of blowflies, beetles, and ants in the postmortem period but ants in Australia are changing, so what does that mean for long-term criminal investigations? We are now looking into how these changes in species will have a different impact on cadavers as there will be ongoing implications in the forensic space.”
Source: forensicmag.com
As a digital subscriber to Criminal Legal News, you can access full text and downloads for this and other premium content.
Already a subscriber? Login
