Date of Award
Master of Arts
Jill D. Pruetz
Forensic anthropology is often connected with the identification of human skeletal remains using various skeletal analyses. However in a medicolegal context, forensic anthropologists aid investigators by collecting information on the condition of skeletal remains. Little research has been conducted on the differences in decomposition rate between subjects in outdoor and insect restricted environments in central Iowa. Limited accessibility to appropriate facilities in the Midwest for a comparison between indoor and outdoor decomposition rates has prevented comprehensive research with human or swine remains from being conducted. A study on the impact insect restriction has on the decomposition process and how subject condition interacts with other variables is needed to determine the degree of differential decomposition.
The research described in this thesis models a forensic context and serves as an introductory study of decomposition and skeletonization of insect restricted remains. The study was conducted in a rural field in central Iowa between July and October 2008. The primary variables examined for the study were insect restriction, duration of containment and temperature differences between conditions. Documented through daily notes and photographs, five male juvenile swine were placed in predetermined conditions, one as a control outside while the remaining four were sealed in plastic totes to be opened on set days until study conclusion after 100 days.
During daily observations or at container opening, each subject was given a predetermined numeric score based on the degree of decomposition exhibited. These scores served as dependent variables during analyses, with independent variables being time since death, temperature, relative humidity, accumulated degree days and insect restriction. Temperature and humidity levels at the site were recorded using HOBO data loggers.
Comparisons between subjects allow for statements to be made concerning insect restriction. Results show between conditions that containment in plastic totes significantly slows the rate of decomposition of remains. The greater difference in decomposition is observed between the control subject 5 and subjects 2 and 1, opened at day 40 and 80 respectively. Also notable is that the containment of subject 4 produced only a slightly slower rate of decay than the control, whereas the sealed subjects decay rates were significantly affected. It appears that the sealed containment conditions produced an increase in temperature and relative humidity as well as restricted insect access to the remains, therefore slowing the decomposition process. Further research is necessary to determine the precise sources of the differential decomposition rates.
Elizabeth K. White
White, Elizabeth K., "Boned up: differential decomposition of child-sized swine remains to model a forensic context" (2009). Graduate Theses and Dissertations. 11062.