The First Pests

Rats and cockroaches take the top spot as the main urban pests plaguing city dwellers. 

But a new genetic study suggests that bed bugs may have been one of the first to irritate humanity since the very first cities popped up thousands of years ago. 

For their study, researchers analyzed the genomes of 19 bed bugs collected in the Czech Republic – nine from human homes, and the rest from bat roosts. Their goal was to trace how these pests evolved and spread. 

The team found that bed bugs originally fed on the blood of an unknown host more than 100 million years ago before adapting to bats. Then their lineage split around 245,000 years ago when some of them began feeding on cave-dwelling humans. 

The bugs eventually split into two genetically distinct populations that have curiously not yet diverged into separate species.  

However, researchers found that the insects have faced some hard times since the last ice age, some 20,000 years ago. 

“Initially with both populations, we saw a general decline that is consistent with the Last Glacial Maximum; the bat-associated lineage never bounced back, and it is still decreasing in size,” said lead author Lindsay Miles in a statement. “The really exciting part is that the human-associated lineage did recover and their effective population increased.” 

That recovery appears to have started around 12,000 years ago and their populations skyrocketed roughly 8,000 years ago – timing that matches the rise of large permanent settlements, such as Çatalhöyük in modern-day Turkey and Uruk in ancient Mesopotamia. 

Co-author Warren Booth said it’s likely that the parasites latched onto their human hosts when our ancestors decided to leave their cave abodes. 

“When we started to live in cities … (people) had their own bedbugs with them,” Booth told the Guardian. “And then, as civilization spread across the world, the bugs spread with them to the point where they’re now ubiquitous in human society.” 

While some scientists are skeptical of crowning bed bugs the first true urban insect pest – head lice, for example, have been with humans far longer – the authors say the findings highlight how closely human history has been intertwined with the bed bug. 

The study also lays the groundwork for future research into how bed bugs have adapted to city life and developed resistance to modern pesticides.