My New Level Of Hell Just Opened Up

I'm afraid of roaches.  Terrified to the point of paralysis.  Absolutely cannot deal with them on any level.  I'll burn my house down around one rather than face it.  I've set off a bug bomb in my car because one sneaked in through a cracked window.  I've thrown away heirlooms without hesitating because they were spotted making themselves at home inside...

It's called Katsaridaphobia.

This is why I have cats.  They just love to take them down on my behalf, like my own personal Army of Darkness.

Now, news of their evolution, (especially against me in particular as I choose to believe because they hate me and know I'm afraid) has hit the airwaves.

In the ongoing battle between humans and cockroaches, a new study finds that roaches evolved their taste buds to make sweet insecticide baits taste bitter.  Now, the roaches avoid the baits and thrive, to the chagrin of homeowners and fearful humans everywhere.

Plenty of insects evolve resistance to pesticides; they gain the ability to break down poisons without dying. German cockroaches, on the other hand, evolved what's known as a behavioral resistance to baits.  They simply stopped eating them because they have sensitive taste buds.

German cockroaches are the small, scuttling roaches frequently seen in human habitats, including homes and restaurants.  They grow to be about a half-inch (1.27 centimeters) long and are omnivorous, scavenging everything from grease to starch and creeping us out for decades.

Beginning in the 1980s, many pest control companies switched from using spray insecticides to control cockroaches to using baits.  The baits combine sugars with insecticide so that roaches eat them, thinking they are sugary snacks, return to their nests and die.  Ideally, the other cockroaches in the nest then cannibalize their dead relative, getting a dose of the poison, too.

This worked for a while.  But in 1993, several populations of German cockroaches around the world were thriving in spite of the baits. The roaches were refusing to eat the glucose, or sugar, that was supposed to make the bait appealing.

Pest control companies switched up the sugars in their baits to keep them working, and for years, no one knew how the roaches had developed their glucose aversion.

In normal roaches, some of the cells in the taste hairs respond to bitter tastes and others to sweet tastes.  In roaches that avoided glucose, however, there was one change.

"The system was perfectly normal, except for the fact that glucose was being recognized not only by the sweet-responding cell, but also by the bitter-responding cell," one scientist said.

In other words, the glucose-averse roaches tasted sweet things as bitter and thus avoided them.  (Even cockroaches have standards, it seems.)

Roaches could have evolved this response simply because people started poisoning them with sweet baits.  It's also possible that the trait goes way back in cockroaches' 350-million-year history.  Some plants produce toxic bittersweet compounds that roaches would have needed to avoid before humans came around.  Once humans started building dwellings and roaches moved in, they may have lost this sugar-avoidance ability in order to snack on humans' leftovers.  When people started developing sugary baits, the pre-adapted anti-sugar trait may have re-emerged.

Either way, the finding has implications for pest control. The industry has replaced glucose in baits with another sugar, fructose, but evidence already suggests that roaches are evolving to avoid fructose, too.  The industry needs to vary baits frequently and make multiple types at once to stay a step ahead of the roaches.

God help us all!