Cockroaches evolve in 5 years to avoid poison bait
Study finds the pests adapt quickly to recognise the sweet taste of glucose used in poison baits, an evolutionary aversion that saves their lives
People have been getting rid of cockroaches for decades by laying bait mixed with poison. But in the late 1980s, in the test kitchen of a flat in Florida, something went very wrong.
A killer product stopped working. Cockroach populations there kept rising. Mystified researchers tested and discarded theory after theory until they finally hit on the explanation: in a remarkably rapid display of evolution at work, many of the cockroaches had lost their sweet tooth, rejecting the corn syrup meant to attract them.
In as little as five years, the sugar-rejecting trait had become so widespread that the bait had been rendered useless.
"Cockroaches are highly adaptive and doing pretty well in the arms race with us," said North Carolina State University entomologist Jules Silverman, who discovered the glucose aversion in that Florida kitchen.
The findings illustrate the high-speed evolutionary prowess that has helped make cockroaches so hard to stamp out that it is jokingly suggested they could survive nuclear war.
In a study published on Thursday in the journal Science, Silverman and other researchers explain the workings of the genetic mutation that gave some roaches a competitive advantage that enabled them to survive and multiply.
The key is certain neurons that signal the brain about foods.