Nonconsumptive Effects of Predatory Chrysomya Rufifacies (Diptera: Calliphoridae) Larval Cues on Larval Cochliomyia macellaria (Diptera: Calliphoridae) Growth and Development

Forensic entomologists often rely on development data associated with a given species to estimate when it colonized human or other vertebrate remains. In most instances, these development studies are based on single species reared in isolation in the laboratory. Not surprisingly, the current study found Ch. rufifacies ES did not impact the development of first- or second-instar C. macellaria, which are typically not preyed on by Ch. Rufifacies; however, development of third-instar C. macellaria, which do experience predation, was impacted. First, larvae were longer than those in the control (deionized water, dH2O). Filtering the ES and removing the associated bacteria and byproducts >0.2 µm dampened the previous impact observed by the unfiltered ES on third-instar C. macellaria. Second, third-instar C. macellaria treated with unfiltered ES completed pupariation 8 h quicker than the controls. Filtering the ES lessened this effect by 50 percent. Finally, third-instar C. macellaria treated with filtered or unfiltered Ch. rufifacies ES reached adulthood ~5 h faster than controls treated with dH2O. The study concludes that these data have large ramifications for forensic entomology, since multiple species being present on decomposing remains is not uncommon. Understanding the impact of associated ES produced by interspecific cohorts on associated development could lead to more precise estimates of the minimum postmortem interval for forensic investigation of decomposing remains. (Publisher abstract modified)