Bed bugs, Cimex lectularius: Undercover agents in forensic investigations

Area of Science:

• Forensic Entomology
• Molecular Biology
• Genetics

Background:

• Insects are crucial in forensic science for estimating time since death and linking individuals to crime scenes.
• Bed bugs (Cimex lectularius), ectoparasitic insects feeding on vertebrate blood, have potential forensic applications.
• Previous studies demonstrated successful autosomal short tandem repeat (STR) profiling from human DNA in bed bugs.

Purpose of the Study:

• To evaluate the forensic utility of bed bugs for rapid stain identification (RSID™) of human blood.
• To determine the limitations of using bed bugs for Y-STR profiling.
• To assess the impact of time post-blood meal (PBM) on DNA quality and profiling success.

Main Methods:

• Bed bugs were fed human male-only or pooled (female:male) blood for 30 minutes.
• Samples were collected at 12-hour intervals up to 108 hours PBM.
• RSID™ testing and Y-STR profiling were performed on bed bug carcasses.

Main Results:

• RSID™ testing for human blood was successful irrespective of blood meal type and collection time PBM.
• Complete Y-STR profiles were obtained from bed bugs collected within 60 hours PBM.
• DNA quantity decreased, and the degradation index increased with time PBM.

Conclusions:

• Bed bugs can serve as a valuable source of human blood for forensic DNA analysis.
• Y-STR profiling from bed bugs can link individuals to a crime scene or exclude male suspects.
• Further research with larger sample sizes and diverse donors is recommended.