What is the significance of a maggot mass in PMI estimation?

• A. Mass heat from dense larval aggregations can accelerate development, so PMI calculations must account for mass effect and local temperature
• B. Mass only matters for identification, not PMI
• C. Mass has no effect on development
• D. Mass decreases growth due to crowding

Answer: (B)

Dense maggot masses generate heat through the collective metabolism of many larvae, so the temperature inside the mass can rise above the surrounding environment. Since larval development rates are strongly temperature-dependent, this higher mass temperature speeds growth compared to what ambient temperature alone would predict. As a result, PMI estimates that ignore the mass effect can be biased, often underestimating the actual time since death because the larvae develop faster than ambient-based models anticipate. To estimate PMI accurately, investigators try to assess the temperature experienced by the maggot mass (or use development data that incorporate mass effects) and apply a thermal model that uses that corrected temperature. This concept matters more than any notion that mass is only useful for identification or has no impact on development.