Scientists in Malaysia recruit bed bugs to help solve crimes

Scientists in Malaysia have found that bed bugs might help police identify suspects after discovering that the household pest can preserve human DNA for weeks.

In a controlled laboratory at the Science University of Malaysia (USM) in Penang, scientists have been raising colonies of tropical bed bugs, Cimex hemipterus, to study how long the insects retain genetic material from a blood meal.

Their experiments show that DNA extracted from the bugs can provide information about a person’s physical traits for up to 45 days after feeding.

Quoting entomologist Abdul Hafiz Ab Majid, AFP reported that the insects, usually dismissed as “the enemy in the blanket,” could also act as “spies” at crime scenes.

According to him, analysing blood inside the bugs could help determine details such as gender and features like eye, hair and skin colour. Researchers used STR and SNP markers — DNA sequences typically examined in forensic labs — to identify these traits.

In the USM lab, bed bugs are kept in mesh-covered containers wrapped in dark plastic to mimic the conditions they prefer. Paper strips inside give the insects something to climb. The room is maintained at around 23–24 degrees Celsius, and each bug consumes a tiny amount of blood, less than a full droplet, during feeding.

The study, titled “Human profiling from STR and SNP analysis of tropical bed bug, Cimex hemipterus,” appeared in Nature’s Scientific Reports two years ago and marked the first recorded forensic work involving this species.

Hafiz said bed bugs may be more reliable than mosquitoes or flies because they cannot fly and tend to stay within a short distance of their feeding spot, roughly six metres, making them potentially valuable if other evidence has been removed. The insects also hide well, meaning they may survive attempts to clean up a scene.

Postdoctoral researcher Lim Li, part of the same team, has even offered her own arm during trials. She joked that she had been a “willing victim” while testing how quickly human DNA inside the bugs breaks down.