Blind validation of insect age estimates for Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae)

Knowing the age of insects collected from human remains can be informative in death investigations, and when certain assumptions are met, can be useful for estimating the postmortem interval (PMI). Such estimates often are based on species-specific development data that are temperature-dependent, can be highly variable, and therefore prone to error. Legal and professional pressures have been placed on forensic disciplines to develop a more scientific approach to forensic sciences. One area within forensic entomology in need of restructuring is the approach to understanding error associated with making PMI estimates. Because of this potential error, the methods employed for making such estimates must be validated to quantify the associated error. Validation studies are useful tools for determining accuracy and precision of laboratory and field data. However, few development data sets have been validated. Validation of such data sets is one approach for refining uncertainty associated with insect age estimates and therefore meets the criteria for admissibility in court. Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae) is a primary colonizer of remains in the southeastern USA, and is therefore of great importance in forensic investigations. The objective of this study was to determine the accuracy of estimating the postcolonization interval when applying laboratory-based development data for C. macellaria. This is the first validation of development data for C. macellaria.