Killing Sample
Definition
The portion of collected insects killed immediately in hot water and then fixed in 70-80% ethanol. It preserves the exact developmental instar present at collection and forms the permanent voucher specimen.
- Method
- Killed in hot water, fixed in 70 to 80% ethanol
- Preserves
- Exact developmental instar at time of collection
- Role
- Permanent voucher specimen
- Evidence type
- Entomological evidence
Common questions
Why is a killing sample necessary alongside live-reared specimens at a scene?+
Live specimens reared to adulthood in the lab confirm species identification but grow past the stage they were at when collected, so a killing sample fixed immediately preserves the exact size and instar present at the scene, which is what the post-mortem interval estimate actually depends on.
Why hot water before ethanol rather than ethanol alone?+
A quick hot-water kill causes the larva to die extended rather than curling defensively, keeping an accurate body length for age estimation, and it also helps prevent the tissue-hardening and shrinkage artefacts that can occur if ethanol is applied to a still-living specimen.
Related terms
- Accumulated Degree Hours/days (ADH/ADD)
- A temperature-corrected measure of thermal energy available for insect development, calculated by summing the degrees above a species-specific base temperature over time....
- Maggot Mass
- A dense aggregate of larvae feeding collectively, often at body openings or wounds. The mass generates its own heat, sometimes 10 degrees...
- 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...
- Rearing Sample
- Live larvae placed in a rearing container with fresh liver or meat, kept at a controlled temperature until adults emerge. Adult morphology...
- Succession Wave
- A cohort of insect species arriving at a body as one decomposition stage creates the conditions they require. Each wave modifies the...