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Cockroaches, who needs ’em?

Entomologists estimate there to be around a quintillion individual insects on the planet–and that’s just insects. Bugs are everywhere, but how much do we really know about them? Jeff Lockwood to the rescue! Professor Lockwood is answering all your bug questions–one at a time, that is. Send your question to him care of blog@oup.com and he’ll do his best to find you the answer.

Would there be any negative repercussions to wiping out all cockroaches?

A world without cockroaches would pretty much keep on doing what it’s doing now. Probably. At least if by “all cockroaches” you mean the 30-or-so species that share our homes. That would still leave about 4,470 species in the wild to gobble up the detritus of the natural world.

Of course, it is possible that eliminating 30 abundant species could trigger an ecological cascade that would diminish important “ecosystem services” (the new-fangled catchphrase that ecologists use to describe all of the processes in the biological world that make the Earth habitable—even comfy—for humans). Any imaginative ecologist could come up with a series of events that might follow the elimination of pesky cockroaches and make the world less to our liking. For example, without cockroaches to feed the rats in the sewers, the hungry rodents take to the streets, becoming more aggressive and attacking babies. That’s rather outlandish, but if some Hollywood producer is reading this blog and wants a screenplay based on my idea, I’ll flesh it out a bit further.

Some years ago, Paul Ehrlich—a really smart ecologist from Stanford (where most people are supposedly brilliant, although one must wonder about a school that thought the color “Cardinal” should be plural and believes that a foam rubber tree is a compelling mascot, but I digress) made the comparison of ecosystems to airplanes. Here’s how it works. Imagine that you’re flying at 30,000 feet and some rich guy from First Class comes back into the Economy section and offers everyone $100 for a single rivet on the left wing.

Image Credit: ‘Cockroach, Insect, Bug, Pest’, Photo by Republica, CC0 Public Domain, via pixabay.

Well, everyone knows that airplanes are over-engineered and losing one rivet surely won’t be a problem. So, you agree. He passes out the cash and a rivet pops out of the wing. And all’s well. So the rich guy repeats his offer. Everyone figures that two rivets won’t be a big deal. You can where this is heading. At some point, the next rivet becomes very valuable, and nobody is willing to take any amount of money. Think of species as biological rivets. For some ecosystem it could be the case that a popping a roach-rivet would result in a wing falling off, and things would go to ecological hell in an entomological hand-basket.

Setting aside the possibility that a cockroach-free world would have bad consequences for our physical well being, there is another reason why wiping out species—even ones that seem repulsive—might have negative repercussions. In fact, I rather favor this argument. In short, cockroaches are beautiful and it is a moral virtue to protect beauty. Of course, cockroaches aren’t pretty (at least for the most part—but check out some of the Australian species). However, when one learns about their incredible evolution and fantastic biology, a deep kind of wonder and aesthetic appreciation emerges.  The earliest cockroaches skittered through forests of the Carboniferous, so these creatures are the product of 350 million years of evolution. Today, some cockroaches weigh more than an ounce and reach a length of nearly 4 inches. There are species that eat wood and digest the cellulose using symbiotic protozoa. Sound familiar? It should, as this is how termites consume wood—and the early cockroaches gave rise to the termites. Consider that if all the offspring of a single German cockroach (which is actually from Africa, as is the American cockroach; there is no African cockroach—go figure) survived and reproduced for 1 year, we’d have 3.2 billion insects that would stretch 28 miles end-to-end. I could go on and the cockroaches most assuredly will.

My point is that these are marvelous creatures with a remarkable story. I know this is hard to keep in mind when turning on the lights and finding a cockroach confab in your kitchen (I earned my PhD in entomology from Louisiana State University and lived in a Baton Rouge mobile home park, so I had my share of encounters). But if we were to wipe out all of the cockroaches, we would lose something beautiful—and there would be negative repercussions to our character. In some way (maybe only a very small way, but humility might be among the most needed of the virtues these days), we would be diminished.

Featured Image Credit: ‘Insect, Cockroach, Eye, Animal’, Photo by ddouk, CC0 Public Domain, via pixabay.

Recent Comments

  1. Bryan

    Hi Jeff, I agree with you after reading what you wrote in the article. I also believe it’s impossible to wipe out any single cockroach species right? I’m not actively seeking to wipe them out but I do take a lot of effort to prevent them from entering my house.

    I’m gonna have to disagree with the beauty of cockroaches though, maybe except the cute little Madagascar hissing cockroach :)

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