What is it about cockroaches that fills us with such dread and fascination all at once?

Is it because, as much as we want to deny it, we share so many qualities with them?

When scientists recently mapped their genetic code, they found a stunning 20,000 genes. Guess who else has about that many genes?

We also share a wonderfully symbiotic relationship over one of the most defining traits of modern civilization: trash.

We like to make it. Cockroaches like to make babies in it.

Maybe we’re so tight with roaches because deep down inside, when the world comes tumbling down, cockroaches are the only ones that will stand at our side. Yes, insect species are on a devastating downward trajectory — a recent study suggests more than 40 percent of the world’s insect populations are in swift decline. But the same report suggests the cockroach population is likely to boom despite the chemical bombardment we’ve subjected them to.

Our blind and futile drive to poison roaches may have taken a terrible toll on other insects — and maybe even our own health. (Photo: SiNeeKan/Shutterstock)

The world may not end with a bang. It may not end with even a buzz. But there will always be the pitter-patter of tiny cockroach feet across the trash-strewn ruins of a post-Apocalyptic world.

At least, as long as there are humans to make that trash. Because one thing that cockroaches, for all their genetic gifts, cannot withstand is the loss of us — and our dirty habits.

After all, their entire civilization came to dominance on the back of our own.

“They have gone from the caves to our agricultural societies, to exploring the world on ships, to flying around on airplanes,” Dini Miller, an urban entomologist at Virginia Tech, tells Mashable. “They have just come with us the whole way.”

What’s more, cockroaches may have picked up on the best parts of human society along the way. Studies suggest they recognize each other as individuals and family members. They talk to each other. And they make decisions as a group that will benefit their entire clan. They’re a micro-model of the civil society we could only hope to be.

(Some may have even watched a few Bruce Lee movies.)

That stalwart dedication to humanity — the shared experience of civilizations rising in parallel — may certainly account for the fascination we might feel towards them.

But how about that dread? Why does one only have to rear its twitching antennae to incite a mad squishing spree from any nearby human?

Most of the cockroaches we live with — the American or Germanic varieties — don’t sting. They don’t even stink when you squish them (which you really shouldn’t.) And, most importantly, they’re not nearly as disease-y as we make them out to be.

While studies have found that by eating our excrement, cockroaches may spread pathogens, a 2008 World Health Organization review concluded “definitive evidence that cockroaches are vectors for human disease is still lacking.”

But maybe that last fact is also why deep down inside, cockroaches fill us with such existential dread. They take such good care of us because we’re sort of like livestock to them.

“They don’t want to hurt our populations,” entomologist Tim Kring tells Mashable. “In a way, they’re farming us by not spreading disease to us.”

So whether you consider them friends to humanity or its secret overlords, there’s one abiding truth to our relationship. We’re going to be with each other until the very end.

And in this increasingly hostile world, that kind of loyalty should count for something. Let’s be good to each other.

Related on MNN:

How to stop worrying about cockroaches and learn to love our 6-legged overlords

As long as there are humans, there will be cockroaches.