It’s a terrifying pest, a menacing insect that can ruin your home and compromise your sanity. The species Cimex lectularius L, commonly known as bed bugs, is on the rise across the United States, and TU researchers are working to prevent further infestation. TU Assistant Professor of Biology Warren Booth recently published his latest findings on the origin of bed bugs in the science journal Molecular Ecology.
“Bats are considered the ancestral zoophilic host of bed bugs, but the association with humans likely is much more ancient, going back to the time when humans and bats sheltered together in caves,” Booth said.
Widespread use of DDT and other powerful pesticides nearly eradicated bed bugs in the 1940s and 1950s, but Booth said today’s resurgence points to many factors including the bug’s evolution of insecticide resistance, increased national and international travel, global commerce and the growth of thrift shops.
Booth and his team of biology students investigated more than 700 individual bed bugs collected from human dwellings and bat roosts at multiple locations in 13 countries. Gene fragments were analyzed for commonalities between the bed bugs found on bats and those in human quarters. The study revealed two defined genetic groups; one of bat-associated bed bugs and another strictly associated with humans.
“Our research supports the existence of two host-associated races in bed bugs based on significant genetic divergence of populations on two sympatric host species,” Booth said. “The data suggests the ancestral host of bed bugs was bats, with one or more human lineages diverging, following the movement of humans out of shared cave domiciles.”
TU research empirically supports the theory that human bed bugs evolved into an independent race of parasites from those found feeding on bats. Also, bed bugs derived from bats reported approximately 2.7 times more gene variations than those associated with humans. The results suggest an ancestral founding event where a limited number of genetic variants established the human associated-lineage, which could provide insight into the stability of bed bug populations, Booth said. “Population establishment, high turnover and extinction events are common with little opportunity for the introduction of new adaptations, likely due to human-mediated movement and frequent interventions through pest control.”
Armed with this new information of bed bug ancestry, Booth and his research lab will continue studying the parasite’s origin and behavior. The removal of bed bug populations in human dwellings costs residents and business owners millions of dollars each year, and treatment often is not guaranteed. Although earlier studies have proven bed bugs are not disease carriers, Booth said further research is needed to permanently eliminate populations.