Entomology-based methods for estimation of postmortem interval

Abstract

Forensic entomology involves the use of insects and other arthropods to estimate the minimum time elapsed since death, referred to as minimum postmortem interval (min PMI). This is based on the assemblage of insects found in association with remains, and most often, the time required for development of the first colonizing insects to develop to their size/ life stage at time of collection. This process involves the accumulation of appropriate data for the development of the species of insect at a variety of relevant temperatures and consideration of the other biotic and abiotic factors that may affect developmental rate. This review considers the approaches to the estimation of min PMI, focusing largely on the age estimation of specimens collected from remains and the limitations that accompany entomology-based PMI estimations. Recent advances and newly developed techniques in the field are reviewed in regard to future potential.

Are animal models predictive for human postmortem muscle protein degradation?

“…PMI estimation in later stages is usually even more difficult as the range of available methods is far smaller. In postmortem periods, starting from approximately 72 hpm, forensic entomology, the analyses of developmental stages of cadaver-feeding insects, can sometimes provide information about the minimum PMI [ 13 ]. But also, this method is limited in many cases, e.g., by insect accessibility (bodies discovered indoor, drowned, or covered bodies, etc...), or certain threshold temperatures for the development of different species [ 12 , 14 ].…”

Modeling Temperature Variations Using Monte Carlo Simulation: Implications for Estimation of the Postmortem Interval Based on Insect Development Times*†

“…The positive association of insect development with temperature is well established (1,2). It is this association that allows for insect development to be used as a proxy in the estimation of the postmortem interval (PMI) of bodies where time of death is unknown (3,4).…”

“…One of the commonly applied methods in estimating the time since death is the use of accumulated degree‐days (ADD) or hours (ADH) (5). This method utilizes the physiological energy budget required for development with an assumed linear regression which predicts development based on different temperatures over the developmental history of the larva (2,3). The average development per hour or day is added together to provide an accumulated effect of temperature and time, and is thus also known as the thermal summation model (2).…”

“…This method utilizes the physiological energy budget required for development with an assumed linear regression which predicts development based on different temperatures over the developmental history of the larva (2,3). The average development per hour or day is added together to provide an accumulated effect of temperature and time, and is thus also known as the thermal summation model (2). This method therefore requires precise recordings of temperatures and time to improve the accuracy of the PMI estimation.…”

“…When the collection of insect evidence is only performed at the time of the autopsy (6,7), or even after the autopsy (8), there are a number of factors that must be considered. Firstly, the temperature of the death scene and the time that the body was removed are essential pieces of information (2). Secondly, information regarding the storage of the body prior to the autopsy (time and temperature of refrigeration) (1) and, lastly, when the body was removed from the refrigerator are additional data that must be recorded.…”