Cockroaches 101: How To Kill One On the Run

Having recently tipped you off to the most effective way to swat a fly, Lab Notes is now proud to share the secret to killing a skittering, running-for-its-life cockroach. Thanks to research on animals’ predator-escape mechanisms (which we’re sure has relevance to deep mysteries about neural circuitry, or evolutionary biology, or something), it can now be revealed that the best way to smoosh a roach is to aim for a 90-degree angle from where the thing is currently headed (that is, figure it’ll make a sharp right or left turn) or a 180-degree angle (that it’ll reverse course).

Yes, you might need assistance to cover all three possibilities. A 3-to-1 ratio of humans to roaches is about the right show of force, given how the things have outsmarted and out-reproduced us for so long.

As scientists led by Paolo Domenici of Italy’s Istituto per l'Ambiente Marino Costiero report in Current Biology, cockroaches fleeing predators seem to choose an escape route at random. “By using one of a number of possible trajectories,” said Domenici, “cockroaches may behave with sufficient unpredictability to avoid the possibility that predators will learn their escape strategy. The predator is made to guess.” But roaches do not run in random directions. Instead, find the scientists, they select an escape route at only a few fixed angles from the threat: a 90 or 180 degree angle from the attack. “This is where squashing could be aimed,” Domenici said, “although we like cockroaches and would recommend no squashing.”

Each to his own.