Eideard

Cockroaches lose sweet tooth to survive – Evolution rocks!

with 3 comments

For decades, people have been getting rid of cockroaches by setting out bait mixed with poison. But in the late 1980s, in an apartment test kitchen 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…

In a study published Thursday in the journal Science, entomologist Jules 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.

In normal cockroaches, glucose excites neurons that tell the brain “Sweet!” In the mutant insects, glucose activates neurons that say “Sweet!” and ones that say “Yuck!” The “Yuck!” neurons dampen the signal from the others, so the brain gets the message the taste is awful. This unusual nerve activity appeared in glucose-hating cockroaches collected from Puerto Rico as well as descendants of the Florida insects…

The new work is nifty science. But does it explain why you can’t get rid of the little buggers in your kitchen?

Probably not, said Coby Schal, another study author at North Carolina State…

Frankly, if the bait you put out isn’t working, it’s probably because you’re using it incorrectly, suggested Schal, who said he consults to the pesticide industry free of charge…

It’s not clear when the Florida cockroaches first encountered bait with glucose or how quickly they ditched their taste for the sugar, he said. But he said it’s reasonable to estimate that it took maybe only five years for that glucose aversion to spread to so many cockroaches that the bait was no longer effective. That’s about 25 generations of German cockroaches, which can reproduce about one to three months after they’re born, Schal said.

The glucose aversion may have arisen in an individual cockroach in response to bait. Or it may have already been present in just a few individuals when the arrival of the bait suddenly gave them an advantage for surviving and reproducing. Their offspring would inherit the trait and increasingly replace other cockroaches.

Yup. It surely helps that the scientists devising methods to counter cockroach infestation needn’t wait and rely on evolution – even the fast-paced variety – to invent their responses to natural selection.

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Written by Ed Campbell

May 25, 2013 at 8:00 pm

3 Responses

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  1. Reblogged this on Living out of Eden and commented:
    Even cockroaches do better with poison, than us.

    Living out of Eden

    May 25, 2013 at 8:55 pm

  2. Oh great, even cockroaches now evolved enough to avoid corn syrup. That’s more than I could say about most of us.

    List of X

    May 25, 2013 at 11:22 pm

  3. Hmmm… food for thot, alright. I’m either gonna have to move to the frozen north, or start learning the language of the victors to survive. *picks up cockroach dictionary and begins conjugating verbs*

    sisteranan

    May 26, 2013 at 4:58 pm


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