The Fascinating Truth About the World's Oldest Pests: Cockroaches
When Cockroaches Were King
Most people will look with disgust upon a cockroach but as for myself, I have to stare at them with wonder. They are one of nature's most perfect creations. How do I know? Because the oldest cockroach fossil ever found was 350 million years old. To put that in perspective they predated the very first known dinosaurs by 150 million years and were around not only to watch their demise but also remain in our world today in a nearly unchanged form. In fact they've needed to evolve so little in all this time that fossils of the Mylacris species are nearly identical to living specimens found today.
By the time the Carboniferous Era came along, some 220 million years ago, cockroaches were so dominant a life form that paleontologists affectionately nicknamed this time period the Age of Cockroaches. At the time they were busy evolving to be the first living things on earth to master powered flight. They did this through the use of two sets of soft wings. This may not sound like much but it was a big step. Flight made traveling fair distances easier and the sky was free from competition and predators. They still ate the vegetation at the time and grew pretty big. In 1999 a student at Ohio University, Carly Easterday, unearthed a fossil of Arthropleura pustulatus, the largest cockroach fossil known. It dated back 300 million years and measured three and a half inches long, with a wider body than most modern roaches. The find was a great discovery as insects rarely preserve well in fossils (because of their lack of bones or hard shells.) This specimen was so detailed that its mouth, antennae, and the veins on it's wings could be clearly seen. Because of the problems insects have with fossilization this might not have been the largest cockroach living at the time. Indeed we are still finding bigger dinosaurs than in decades past.
Large size in these early cockroaches was for good reason. At the time they were likely the main course for many large amphibians, early reptiles, and other insects. Other insects had the same idea and centipede ancestors could grow up to five feet long and a foot wide. It paid to be large and flighted.
Modern Day Cockroaches
There are over 3,500 species of roaches currently believed to be living on earth today. Of these only 57 species reside within the US and only 20 or so species are equipped to live in manmade environments, that's less then 2% of all roaches. Not to fear though, where roaches leave off the termites will pick up. Termites are believed to have evolved from roaches around 70 million years ago.
Still cockroaches thrive where other species usually die off. None are known to be listed as endangered. Giant Cave Cockroaches are the largest known living species and can grow up to 4 inches in length, but they are not a pest species. Numerous pest species however are the fastest known runners on earth in comparison to their size. They have been clocked at 12 feet per second, quite an athletic feat! Even more amazing is their ability to live off the scantest of food. Several species even eat their own shed skin and empty egg cases. Cardboard seems a delicacy to many. However the most amazing fact about them lies in their tenacious ability to live through almost anything. Most people think it's an urban legend that cockroaches can live a week without a head, a little joke spread around by someone who was fed up with having too many of them in their home. However, this is not a myth. Death Head Cockroaches have six brains spread out through their bodies which regulate their biological needs, only one of these is in their head. The rest are in their legs. Since roaches do not have lungs (they breath through spiracles within each of their body segments that deliver oxygen straight to their bodies without the need of blood) and they do not have mammalian blood pressure (that would lead to a death from bleeding to death) they can indeed live, hypothetically possibly as much as month without their head. They will however eventually die to dehydration or possibly starvation, the cost of not having a mouth. Since they can live on such scant food (being cold blooded and all) then they can last for quite awhile. Interestingly cockroaches also have the highest tolerence for radiation known to any living species of animal, being able to absorb and live through 6-15 times the dose needed to kill a human.
Cockroaches today come in more than 4,000 colors, shapes, and sizes. Most live in tropical regions and many still retain the ability to fly, although there has been some improvements in their wings. Now instead of two soft pairs of wings they have one soft pair used for flight and one stiff pair used to protect the soft pair. Some have lost their wings alltogether. The heaviest of the known roach species, the Rhinoceros Cockroach, can live in excess of ten years, far beating out most of the insect species on the planet in longevity. It also weighs in at a hefty 33.5 grams.
Cockroaches as Pests
Cockroaches can be more than just pests, they can be a devastation to a manmade structure. People have been battling several roach species for hundreds of years since they brought them home as unsuspecting castaways on ships from tropical climates. The names of the pest roaches reveal much about our own psychology. You can bet with confidence that the loathed German Roach was not named by Germans, nor were the Oriental Roaches named by anyone of Asian decent. In fact most of the pest species are named after countries they didn't originally come from. Still, they provide an easy scapegoat don't they?
German cockroaches are probably the widest known simply because they can make rabbits look like they're not trying (in relation to their reproductive abilities.) They gain sexual maturity at a younger age than most species and also lay more eggs, which the females carry on their back and protect from things that might kill an abandoned egg sack. Since they are communal creatures they will set up a metropolis under your counters faster then you can say Supercalifragelistic Expialidocious. Since they can eat anything including soap, cardboard, and wood, they can also cause quite a bit of damage.
Most people think cockroaches are filthy, but actually cockroaches spend much of their time preening. However this fact should be weighed in with the fact these are also animals who could probably live off eating nothing but rat droppings and pieces of rancid meat that has rolled under the stove. This is why they spread disease.
It's funny to think that the same roaches people claim will inherit the earth someday are the same species that will likely perish without our constant companionship. Being tropical most pest species would die if we didn't heat our home year round.
Domesticating the Roach?
Roaches are now being bred purposely in captivity. The first of these roaches were probably Madagascar Hissing Roaches that were bred in laboratories to do radiation testing. However the laboratory proved to be only one of many niches they filled. With the growing popularity of reptilian pets many people started importing various tropical roach species to breed in captivity as food for their lizards, frogs, and various other reptilian and amphibian pets. Some cultures had already taken to breeding them for human consumption but this is something that has gained little popularity in the West. Finally roaches started being bred as pets themselves. Many of the imported species were ill-equipped to live feral within households making them ideal for domestication.
Roaches can come in all sorts of parrot-like colors and since many aren't capable of biting they were seen as good first pets for children. Their diet might as well been free (table scraps) and their slow metabolism made cage cleaning a practically annual ritual. Madagascar Hissing Roaches are still the best known pet species as they are large and exhibit a hissing behavior when they are threatened that seems to entertain curious onlookers. These cockroaches are also watched like fish by insect enthusiasts who often put at least three males in with a colony of females so they can see the 'satellite' behavior of the less dominant males. Males in this species can be easily distinguished by a bump on their head. Since they are wingless all that is needed to keep them in an open container or aquarium is a ring of Vaseline around the top of the container (so if they climb up they'll slip back down.)