CIDSAC Crimes Against Persons Practice Test 2026 – Complete Exam Preparation

In forensic entomology, estimating the time since death relies on the development stage of insects that colonize a body. For the very early days after death, the first instar larval stage is the most informative because it sits at an early, well-defined point in the blowfly life cycle and has well-documented, temperature-dependent growth data. Eggs may be laid within hours, but their exact age is hard to determine because oviposition can occur over a stretch of time and environmental conditions affect egg development in ways that add uncertainty. Once eggs hatch into the first instar, you enter a short, predictable window before molting to the next stage, and there is robust reference data linking larval size and developmental timing to age under different temperatures. By applying degree-day calculations to the first instars, you can estimate how long they’ve been developing since oviposition, which aligns closely with time since death in the initial days. Later stages, like second instar larvae or pupae, reflect longer intervals and thus provide broader, less precise PMI estimates for those early postmortem days.