Cockroaches don’t have a lot of good press. They’re regarded as dirty and invasive. Even the scientific name for their order, Blattodea, feels like it’s getting grubby footprints all over your nice clean kitchen when you say it.
But that name simply means “avoids the light” in Greek and Latin. Even “cockroach” is an Anglicised version of the Spanish “cucaracha”. There are 4,000 species of cockroach around the world, but only a dozen are thought of as pests. Perhaps their reputation is ill-deserved?
Cockroaches are old – really old. As a species they’ve seen the dinosaurs come and go. Is it a surprise that they can eat just about anything? You don’t get to survive for 350 million years by being picky about your food. Like us, they love sweet and savoury things, but when it’s crunch time they’ll scarf down paper, glue, even hair – and when those run out, some roaches can go without food for a month.
In New Zealand you’re most likely to run into a Gisborne cockroach, a species introduced from across the Tasman. That’s the one with the dark carapace and the two paler stripes down each side. It’s relatively clean-living, and unlike its German or American mates you won’t be picking them out of your food supplies.
There are a lot of legends about how tough cockroaches are, and these are well-deserved. As mentioned, they can go without food for a long time. They can survive sub-zero temperatures. And yes, some species can live for a short time after being beheaded.
The most famous story is about how they’re so hard to kill that they could survive a nuclear blast. This one might not stack up. A big bang like that releases a lot of radiation, and cockroaches can tolerate only six times more of that than humans can.
(For the real nuclear champs, you should look at fruit flies: six times? “Hold my overripe avocado” – try three hundred.)
Our Gisborne cockroach may be everywhere but it doesn’t have any claims to fame. We have to leave things like that to – unsurprisingly – the Australians. Their burrowing cockroach is the biggest and heaviest of the whole order: it’s the length and weight of a K Bar. You can tell when one is in your house because all your furniture is being knocked over.
The Madagascar hissing cockroach, as well as being humungous, is one of the only insects to make sounds by expelling air. In 2007 a Russian cockroach gained the honour of becoming the first animal to get pregnant in space. They’re a diverse bunch and they’ll keep surprising you in interesting ways.
If you find one in your house, you’re much better off chucking it outside than you are squishing it, and the tough little survivor will thank you for it too.