They’re six-legged, hairy home invaders that just won’t die, no matter how hard you try.

Cockroaches are experts at surviving indoors, hiding in kitchen pipes or musty drawers. But they didn’t start out that way.

A new study uses genetics to chart cockroaches’ spread across the globe, from humble beginnings in southeast Asia to Europe and beyond. The findings span thousands of years of cockroach history and suggest the pests may have scuttled across the globe by hitching a ride with another species: people. 

“It’s not just an insect story,” said Stephen Richards, an assistant professor at Baylor College of Medicine who studies insect genes and was not involved with the study. “It’s an insect and humanity story.”