Unlocking the Keys to Cockroach Resilience

The German cockroach "Blattella germanica" one of the world's most intrusive species, likes to live indoors with us. And it appears to be increasingly unphased by common insecticides.

Scientists have been studying certain strains of B. germanica to see how they develop pesticide resistance. They've discovered that several strains have a unique, membrane-bound protein called esterase, which detoxifies some insecticides. Roaches with the enzyme can withstand a whole lot more insecticide than their unprotected relatives can.

Another key mechanism responsible for roach persistence pertains to what's called knockdown resistance, or kdr. This is caused by mutations in nervous system proteins of some insects. Researchers have identified a gene mutation associated with kdr in 83 percent of German cockroach field populations surveyed. And they've also found two new mutations that make the roaches more resistant to pyrethroid and related insecticides.