Bedbugs May Be Humanity's First Urban Pests, Genomic Study Reveals

A new genomic study published in Communications Biology suggests that bedbugs may have been the earliest urban pests to form a symbiotic relationship with humans—predating rats and cockroaches by several thousand years.

Originally feeding on bats, some bedbug populations began adapting to human hosts around 245,000 years ago. This host shift gave rise to two genetically distinct lineages: one that remained bat-associated and another that followed humans into their homes. Researchers from Virginia Tech analyzed the genomes of 19 bedbug specimens and identified two major population booms in the human-associated lineage—approximately 13,000 and 7,000 years ago—coinciding with the emergence of sedentary lifestyles and early urban civilizations such as Sumer.

In comparison, German cockroaches and black rats only began cohabiting with humans around 2,000 and 5,000 years ago, respectively. Some researchers have proposed that lice, fleas, or follicle mites may also have early urban pest credentials, though studies in these areas remain limited.

The study also found that bedbugs adapted morphologically to human environments, with changes in body size, hair, and limb structure. Modern bedbugs have further evolved genes that confer resistance to insecticides, underscoring their rapid adaptation to human pest control efforts.