Minimum PMI (Period of Insect Activity)
Definition
The elapsed time since the first insects colonised the body. Because access may have been delayed, this is a lower bound on the true PMI, not the PMI itself. Also written mPMI or PMIMIN.
- Also written
- mPMI or PMI(min)
- Measures
- Time since first insect colonisation
- Bound type
- Lower bound, not the true PMI
- Limitation
- Colonisation access delay is usually unknown
Common questions
Why can't entomological evidence give the exact time of death rather than a minimum?+
Insects must first locate and access the body, which can be delayed by factors such as burial, wrapping, an indoor location, or time of day at death. Since this access delay is rarely known precisely, the insect-derived clock can only be trusted as a floor on elapsed time, not the true value.
How do investigators account for the gap between minimum PMI and actual time of death?+
They combine entomological minimum PMI with other evidence, such as scene circumstances, witness statements, and pathology findings, to bracket a plausible range rather than relying on the insect evidence alone to fix a single time point.
Does a longer minimum PMI always mean a more reliable estimate?+
Not necessarily. Reliability depends more on how well the insect species, developmental stage, and temperature history were documented than on the length of the interval itself. A shorter, well-supported minimum PMI can be more defensible than a longer one built on uncertain species identification.
Related terms
- Access Interval
- Any period after death during which insects could not reach the body, whether through concealment, refrigeration, submersion, or wrapping. The access interval...
- Colonisation
- The event when gravid female blow flies (or other pioneer species) locate the body and deposit eggs or first-instar larvae. The entomological...
- Larval Age Method
- Estimating mPMI by identifying the oldest, most developed insect stage present, staging it against a developmental timeline corrected for local temperature, and...
- Post-Mortem Interval (PMI)
- The time elapsed between death and discovery or examination of remains. PMI estimation draws on multiple disciplines: soft tissue decomposition stage, insect...
- Succession Method
- Estimating elapsed time from the species assemblage on the body by matching it to a local succession sequence: a known ecological progression...