German Cockroaches Evolve to Avoid Sugar Traps

Posted on May 26, 2013

BBC News reports that a strain of German cockroaches has evolved to avoid glucose, a sugar that is a popular ingredient in roach-bait poison. North Carolina State University entomologists discovered that some German cockroaches are repulsed by glucose.

The scientists say in a release that normal German cockroaches have a sweet tooth for these sugars. However, Glucose-averse German roaches that were forced to taste glucose refused to ingest the sugar, sort of like a human child who spits out bitter-tasting food. The glucose-averse roaches were happy to consume fructose.

Dr. Coby Schal, the Blanton J. Whitmire Distinguished Professor of Entomology at NC State and the corresponding author of the paper, says in a statement, "We don't know if glucose actually tastes bitter to glucose-averse roaches, but we do know that glucose triggers the bitter receptor neurons that would be triggered by caffeine or other bitter compounds. That causes the glucose-averse roach to close its mouth and run away from glucose in tests."

In the video of the experiments some German cockroaches can be seen tasting jam and then backing away from it. Take a look:

The study was published here in the journal, Science.



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