Flying Cockroaches! Heat Sends Your Favorite Pests Soaring
The summer heat may give American cockroaches like this one enough energy to take to the skies.
Summer weather can make for hot, sticky and uncomfortable days. And if staying cool and keeping hydrated aren't enough to worry about, heat waves could cause cockroaches to take to the skies. Yes, you read that right. Flying cockroaches.
"Cockroaches, like all insects, are cold-blooded, meaning their activity rate increases with temperature," said Jules Silverman, an entomologist and professor at North Carolina State University, in an interview with Live Science. (Cold-blooded creatures are ectothermic, which means they depend on external heat to keep their bodies warm.)
This also means that the species of cockroach that are able to fly (and most of them are capable) are probably more likely to do so in warmer places, said Silverman. [Alien Invaders: Photos of Destructive Invasive Species]
If you think that flying cockroaches are especially horrific, you probably live somewhere with a colder climate and a denser human population. Flying cockroaches in the subways of New York have garnered some headlines, but "flight of the cockroach" is not so common up north, said Michael Bentley, staff entomologist for the National Pest Management Association. People in the southern states are likely to miss what all of the fuss is about. "Down in Florida, they fly a lot more," Bentley told Live Science. "They have to cover a greater distance to find food."
In big cities, these insects have ample access to food that doesn't require aerial travel. As a result, the muscles the roaches use to fly aren't as primed. Sweltering summer heat, however, can give them enough energy to spread their wings. They may fly for various reasons, including to find mates, to find food or to escape a predator (or a stomping foot).
No matter where you live, don't expect cockroaches to fill the skies. They aren't exactly ace flyers. "It's relatively controlled, but not as graceful as something like a butterfly," said Bentley. What they do is more of a controlled glide, although their wings do flap. The distance and heights they reach are more akin to those of a cricket than a bird, according to Bentley.
Another important point, said Silverman, is that the cockroaches with which many people are most intimately acquainted can't fly. The small roaches that often live in homes, called German cockroaches, have wings, but they are unable to get airborne. American cockroaches, a less common and much bigger pest, can fly.
If you have a run-in with a flying roach, don't get too concerned: Although it's unnerving, they aren't trying to attack you. "There is nothing dangerous about flying cockroaches, other than an irrational fear driving people to distraction," said Silverman.
by Taylor Kubota
Are cockroaches RADIATION proof?
Reputation: Yuck. Cockroaches are filthy, immortal scavengers that are unaffected by radiation. In a post-apocalyptic world, it will be these dirty little critters that survive. We would be better off without them.
Reality: There are almost 5,000 species of cockroaches, of which only around 30 have any pest-like tendencies. These few malign a group of insects that boasts an astonishing, enriching diversity of forms. Cockroaches are pretty well toasted by radiation.
The sight of a cockroach scuttling across the kitchen floor is distinctly unsavoury. This emotional truth has led most of us to believe that all cockroaches must be similarly repugnant.
But not George Beccaloni, curator of orthopteroid insects at the Natural History Museum in London, UK. He is on the side of the cockroaches. "People have a very biased view of the group," he says.
Cockroaches are found on all continents apart from Antarctica, from rainforests to deserts
Less than 1% of the 4,800 known species of cockroach cause humans any bother, yet few of us give the 99% a second thought. This is manifestly unfair, says Beccaloni.
He points out that there are about as many cockroach species as there are mammals. So writing off all cockroaches, based on our dislike of 30 or so species, "is like encountering a mouse or a rat and then branding all mammals as disgusting vermin," he says.
I take the point, but remain unconvinced. Mammals are spectacularly diverse. I think back to a childhood holiday in Sardinia, where our flat was plagued by cockroaches. How different can the rest of cockroaches be? Beccaloni takes the next half hour to enlighten me.
For a start, they live in a huge range of habitats.
"Cockroaches are found on all continents apart from Antarctica, from rainforests to deserts," says Beccaloni.
The appealingly-named Megaloblatta blaberoides boasts a whopping wingspan of over 7in (18cm)
The abundance of species is greatest in the tropics, and at low altitudes where temperatures are high. However, there are those can cope with extremes. Eupolyphaga everestiana is a montane specialist that lives on Mount Everest at well over 16,400ft (5,000m) above sea level.
Since they live in so many diverse environments, it is not surprising that cockroaches should come in many different shapes and sizes.
The smallest species on record is the ant cockroach, which lives in the nests of leaf-cutter ants in North America. At just a few millimetres long, it is dwarfed by its hosts.
In contrast, the appealingly-named Megaloblatta blaberoides boasts a whopping wingspan of over 7in (18cm).
Larger still is the giant burrowing cockroach from Queensland, Australia. It is wingless, about 3in (8cm) long, and can weigh over 1oz (30g).
Cockroaches of the Perisphaerus genus can roll up into an armadillo-like defensive ball
This cockroach, which would easily occupy most of your palm, might sound alarming. But it could not care less about humans. "The huge rhinoceros cockroach only feeds on bark and dead leaves," says Beccaloni.
Most cockroaches have taken on similar ecological roles, feeding on decaying organic matter and thus making nutrients available to other organisms. "There are indications that the ecological significance [of cockroaches] is massive," says Beccaloni.
For many species, even some humans, cockroaches are also a sought-after snack. This helps explain why many in the group have evolved nifty ways to avoid being eaten.
The banana cockroaches (Panchlora) have opted for a simple camouflage approach: they are green and this helps them to blend in.
Cockroaches of the Perisphaerus genus can roll up into an armadillo-like defensive ball.
The females churn out perfect clones of themselves without any need for males or copulation
The Prosoplecta species have evolved the same distasteful red-and-black colouration as ladybirds. In order to achieve the rounded shape of a ladybird, Beccaloni says, each of their hind wings rolls up at the ends "like an umbrella around itself".
Some species can fire out a defensive spray, like the Pacific beetle cockroach.
Others, like the Madagascan hissing cockroach, make startling noises when disturbed, presumably to unsettle any would-be predators.
Perhaps inevitably, cockroaches have also come up with a plethora of ways to make more cockroaches.
"Cockroaches as a group are one of the most if not the most varied of all insect groups, in terms of their reproductive biology," says Beccaloni.
A few species appear to be wholly parthogenetic. The females churn out perfect clones of themselves without any need for males or copulation. In others, the females can flip between sexual and asexual modes of reproduction depending on the conditions.
The nymphs have razor-sharp mandibles, which they use to slice into her cuticle and feed on her blood
However, in most species the female produces an egg sac. Some simply lay it and move on, but others incubate the egg case in a brood pouch in their body, effectively giving birth to live young.
Pacific beetle cockroaches have abandoned egg cases altogether. The female deposits eggs directly into her brood pouch. There she nurtures them on a milk-like secretion – "the most nutritious energy-rich protein that's yet been discovered," according to Beccaloni – before giving birth to live, well-developed young.
If this sounds familiar, it should. "It's a very similar situation to the placenta of a mammal," says Beccaloni.
In a few cases, the female even cares for her offspring after birth.
For instance, a Thorax porcellana mother carries her babies huddled beneath her forewing. It sounds almost cute, until you learn that the nymphs have razor-sharp mandibles, which they use to slice into her cuticle and feed on her blood. "They are like little vampires," says Beccaloni.
With so many extraordinary adaptations, it would not come as much of a surprise to find that cockroaches really could survive a nuclear blast. But tolerance of radiation is one talent they lack.
There are about as many cockroach species as there are mammals
"It's mostly an urban myth," says Beccaloni.
A human will usually be killed outright by a dose of 10 Grays. "Cockroaches are only about five times more resistant," says Beccaloni.
At first glance that might sound impressive, but it actually means they "are at the lower end of radiation tolerance for insects," he says. Other species can survive doses of radiation ten times as intense, or even higher
By Henry Nicholls
Why are roaches so hard to SQUISH?
Have you ever stomped a roach, just to have it skitter away unscathed?* Or seen one disappear into an impossibly small crack?
Now scientists have figured out how they do that, and the results are terrifying.
The American cockroach (Periplaneta americana, aka “the big ones”) can squeeze through a crack the height of two stacked pennies in about a second—a fact newly discovered by two brave scientists who are probably still seeing roaches squeezing under the doors of their nightmares.
Not only can roaches fit through tight spaces by flattening their flexible exoskeleton and splaying their legs to the side, the researchers found, they can keep running nearly as fast while squished, the team reports Monday in the Proceedings of the National Academy of Sciences. (In roach terms, top speed is 1.5 meters, or 50 body lengths, per second. Scaled up, that’s equivalent to a human running 200 miles per hour.)
Robert Full and Kaushik Jayaram at Berkeley built tiny tunnels and used a roach-squishing machine to test the animals’ limits. (No roaches were harmed—Full says “we only pushed them to 900 times their body weight, and they could still do that without being hurt.” In fact, they ran just as fast afterward.)
“We find them just as disgusting and revolting as everybody else,” Full says. But he also thinks they’re amazing, and is designing roachy robots that can squeeze and scuttle just like the real thing. The robots take inspiration from roaches’ jointed exoskeletons, with a design similar to folded origami.
Full sees roaches and other arthropods—insects, spiders, and the like—as the next big thing in robots inspired by nature. Unlike other soft robots inspired by worms or octopuses, insect-bots with hard exoskeletons and muscles could run fast, jump, climb, and fly, while still remaining flexible.
“We know that cockroaches can go everywhere. They’re virtually indestructible,” Full says. For roaches, being able to scuttle quickly through small spaces has allowed them to spread into virtually every habitat imaginable and outrun their competition. Other insects probably have their own versions of these super-squishing superpowers, too, he says.
The new roach study “transformed how I view a seemingly ‘hard’ animal,” says Daniel Goldman of Georgia Tech, who studies the physics of animal movement.
“Their idea to create a “soft” robot out of deformable “hard” parts is great, and should transform how we think of creating all-terrain robots,” Goldman says.
by Erika Engelhaupt