NEW
YORK (AP) — 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.<br><br>
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.<br><br>
In as little as five years, the sugar-rejecting trait had become so widespread that the bait had been rendered useless.
<br><br>
"Cockroaches are highly adaptive, and they're doing pretty well in
the arms race with us," said North Carolina State University
entomologist Jules Silverman, discoverer of the glucose aversion in that
Florida kitchen during a bait test.<br><br>
The findings illustrate the evolutionary prowess that has helped make
cockroaches so hard to stamp out that it is jokingly suggested they
could survive nuclear war.<br><br>
In a study published Thursday in the journal Science, 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.<br><br>
The key is certain neurons that signal the brain about foods.<br><br>
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.<br><br>
The research focused on the German cockroach, a small kind that can
hitch a ride into your home in a grocery bag, not that big lunk known as
the American cockroach. Such finicky eating habits have also been seen
in these smaller roaches in Southern California, Cincinnati, Indiana,
South Korea and Russia. Scientists are now looking to see if other kinds
of cockroaches show aversion to glucose.<br><br>
The new work is nifty science. But does it explain why you can't get rid of the little buggers in your kitchen?<br><br>
Probably not, said Coby Schal, another study author at North Carolina State.
Tests show that the glucose-hating cockroaches are happy to eat most
types of bait these days, suggesting that manufacturers have removed the
glucose or masked it, he said. (Bait ingredients are a trade secret.) <br><br>
What's more, the researchers found glucose-hating cockroaches in only
seven of 19 populations they sampled from various locations.<br><br>
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.<br><br>
Still, he said, the new work has potential to help many consumers. By
studying how cockroaches evolve to evade our poisons, scientists may
find clues to designing bait that the pests cannot resist.
<br><br>
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.<br><br>
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.<br><br>
Michael Scharf, an entomologist at Purdue University who studies
urban pests but wasn't involved in the new work, noted that since the
1950s, cockroaches have shown they can also evolve resistance to
insecticides. He agreed the latest results should help scientists
develop better products to control roaches.<br><br>
NOTE: Remember Aspartame has changed it's name to further deceive consumers, it is now also called Amino Sweet
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