Poisoned Baits Drive Cockroach Evolution

Evolution is cleverer than you are. Orgel’s Second Rule

A little bit of tempting treat
That smells and tastes so glucose-sweet
Is what a cockroach loves to eat
And so it will, perhaps.
But human beings, as of late,
Present the bugs a different fate
By sweetening the poisoned bait
They’re using in their traps

Appetitive behavior means
There’s coding somewhere in the genes
That link sensilla (small machines
For chemical detection)
With action—bugs approach or flee
If foods are sweet or bitter, see?
Our mixing poison now is key:
A pressure for selection!

But insect populations vary;
Roaches may or may not carry
Genes that make them glucose-wary,
Acting on their brains
If, in our anti-cockroach war
We use these sweetened poisons more,
Such genes will be selected for
Creating different strains

And so, although the people’s goal
Was ultimately pest control
It seems that nature found a hole
And made its own solution
The roaches that we tried to kill
By poisoning their sweetened swill
Outsmarted us—and always will,
Cos such is evolution!

In Science, just out today (yes, I am just that good), a story on rapid evolution of behavioral aversion to glucose in cockroaches, as a response to a strong selection pressure of sweetened poison baits. Behaviorally, these roaches are now avoiding foods with glucose. Physiologically, their gustatory response neurons have changed–sugar-GRN and bitter-GRN respond differentially to glucose and to caffeine in wild-type cockroaches, but in roach population with a history of exposure to sweetened poison baits, glucose stimulates the bitter-GRN response.

Mind you, selection takes place at the level of behavior, so this may or may not be the only proximal mechanism behind the change in behavior. Any change that selectively gets roaches to avoid poisoned baits will be strongly selected for.

We’ve seen this before–our best efforts to eliminate a pest are seen by evolution as just another selection pressure among many. And in the long run, we see time and time again… evolution is cleverer than we are.

And isn’t it beautiful?


  1. had3 says

    Reminds me of a Bloom County cartoon where the roach is bragging about surviving a nuclear war and states they can survive anything. In reply, Opus squishes the roach with his shoe (I don’t remember if I thought it, or it was implied or stated, but the implication was “evolve around that!”

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