Can We Win the War on Cockroaches?

Cockroaches are, if nothing else, admirably persistent -- they can spring back from a 90% population loss just a couple generations. Learn how hardy they are in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff.
Lauren Vogelbam here with great news. Cockroaches are quickly becoming
resistant to several different insecticides all at the same time.
Cool cool, cool one. Michael Scharf, a professor in the
Department of Entomology at Purdue University, along with his team

(00:23):
found that these pests are developing cross resistance to multiple
classes of exterminators insecticides. The team's work was published in
the June twenty nineteen issue of Scientific Reports. The problem
is that each class of insecticides works differently to kill
these critters, so exterminators frequently mix them or switch them
up to combat infestations. Cockroaches are resistant to multiple insecticides, well,

(00:48):
you can see where this is going. Scharf and his
team used apartment buildings in Indiana and Illinois that had
infestations of German cockroaches as their experimental grounds. First, because
tomor g is very glamorous, they caught some of the
roaches and tested them to see which insecticides had the
lowest resistance on the roaches. Low resistance means the roaches

(01:09):
would be more vulnerable to the treatments which the scientists
went on to use for six months. Scharf said in
a press release, if you have the ability to test
the roaches first and pick an insecticide that has a
low resistance, that ups the odds. But even then we
had trouble controlling populations. The researchers rotated three different insecticides.

(01:31):
That method kept the roach population stable over six months,
meaning it neither increased nor decreased. When they mixed two insecticides,
the roach population flourished, according to the press release, flourished
being just about the last verb anyone wants to hear
when talking about cockroaches. When the team used just one
insecticide for the entire six months and the roaches had

(01:53):
low resistance to that particular insecticide, they were nearly wiped out. Well, great, right,
Not really, because if even ten percent of the roaches
had resistance to that insecticide, the population would increase, Scharf said,
quote four to sixfold in just one generation. We didn't
have a clue that something like that could happen this fast.

(02:14):
During this test, the roaches also developed resistance to several
other kinds of insecticides, even if the new generations had
never been exposed to them before. So now what Scharf said.
He recommends combating roaches with more than chemical warfare, including
traps and vacuums. Quote. Some of these methods are more

(02:34):
expensive than using only insecticides, but if those insecticides aren't
going to control or eliminate a population, you're just throwing
money away. Oh and hey, you've probably heard that roaches
can survive a nuclear blast, and the terrible news is
that that appears to be true. Remember the show MythBusters.
Their team set up an experiment that exposed German cockroaches

(02:57):
to different levels of radiation. One group was exposed level
similar to those omitted by the bomb dropped on Hiroshima.
For a month, ten thousand rads, ten percent of the
group was still alive. Maybe we should just go ahead
and bow to our cockroach overlords now. Today's episode was

(03:18):
written by Kristen hall Geisler and produced by Tyler Clay.
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