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Seasonal Effects on Carrion Decomposition and Insect Colonization

Award Information

Award #
Funding Category
Competitive Discretionary
Congressional District
Funding First Awarded
Total funding (to date)

Description of original award (Fiscal Year 2017, $50,000)

Insect colonization of carrion is a continuous, overlapping series of trophic interactions and ecological successions. Insect scavengers, predators, and parasitoids appear to follow predictable colonization patterns governed by a multitude of biotic and abiotic factors, including species competition, decomposition state, weather, and temperature.

Due to its predictable nature, the principles of successional ecology can be applied by forensic entomologists to estimate the period of infestation in decedents. This estimated period of time can then serve as a proxy for time elapsed since death in criminal investigations. Despite its strong ecological foundations, succession based forensic entomology is still a developing field of research. This may negatively affect its reliability for use by expert witnesses.

For successional work, statistical confidence has been hampered by factors such as pseudoreplication and observational-based emphases. These weaknesses can at least partially be attributed to the problematic length of multi-year seasonal studies. The scope of this work fills the need for a multi-season and year successional analysis.

Accordingly, the researchers placed five pig carrion in the University of California, Davis Riparia Reserve each season for two consecutive years. For each carrion, the researchers sampled insects present and recorded state of decomposition over the course of a full year. Additionally, the researchers recorded both historical and concurrent NOAA weather data from the nearby University of California, Davis Experimental Farm. The intent is to analyze annual and seasonal variation of insect succession, diversity, decomposition, and weather through multiple regression analyses.

Finally, the researcher will attempt to coalesce these factors to a form a predictive model of insect succession in decedents. Ultimately, we seek to strengthen the potential utility of successional ecology for expert testimony by forensic entomologists.


Date Created: September 29, 2017