Bedbugs: Humanity’s First Urban Pests Traced to Rise of Ancient Cities.

Bedbugs may hold the distinction of being one of the first insect pests to thrive in human-made urban environments. A recent study published on May 28 in Biology Letters sheds light on how these persistent parasites surged in population as the first cities emerged thousands of years ago.

The common bedbug (Cimex lectularius), which currently infests homes around the world, originally fed on bats. Around 245,000 years ago, a lineage of these insects began feeding on humans—likely starting with Neandertals—and has remained closely tied to people ever since. This shift in diet laid the foundation for their eventual rise as urban pests.

A decade ago, a team led by urban entomologist Warren Booth at Virginia Tech sequenced and studied the genomes of both bat-associated and human-associated bedbug lineages. Their goal was to understand how species evolve alongside human developments. When Lindsay Miles, also from Virginia Tech, later analyzed the genetic data to reconstruct historical population trends, the team uncovered unexpected results.

Both bedbug lineages experienced population declines around 19,000 years ago, likely due to habitat disruptions caused by the retreat of Ice Age glaciers. However, around 13,000 years ago, the human-associated lineage rebounded sharply, leveled off, and then spiked again approximately 7,000 years ago. The bat-associated lineage, by contrast, continued to decline.

Booth and his team believe this population surge aligns with the birth of the earliest cities in western Asia. As human communities transitioned from nomadic to settled lives and began living in close quarters, they created ideal conditions for bedbugs to thrive. The insects interbred, multiplied, and adapted to the new urban ecosystem, marking them as likely the first insect pests to fully exploit city living.

While other urban pests like house mice have been linked to humans for over 15,000 years, they can still survive independently. In contrast, human-associated bedbugs are completely dependent on humans for survival. German cockroaches and black rats joined the urban pest roster much later, around 2,100 and 5,000 years ago, respectively.

Mark Ravinet, an evolutionary biologist at the University of Oslo, who was not involved in the study, highlights the broader significance. He sees bedbugs as a valuable model for understanding how rapidly species can evolve to fit human-altered environments. Ravinet also suggests that similar adaptations may have occurred independently in different regions of the world.

Source: https://www.sciencenews.org/article/bedbugs-first-urban-pests

This is non-financial/medical advice and made using AI so could be wrong.