[Creative Cultivation Program] One cockroach can reproduce 10 million? Why are cockroaches so fertile?

How terrifying is the reproductive ability of cockroaches?

I recently read a piece of news that said: If cockroaches are in an environment with suitable temperature and abundant food, they can form a large family of about 10 million cockroaches in a year! Seeing this, many friends may be shocked. No wonder there are so many cockroaches in our home! Some friends are skeptical. If this is the case, cockroaches would have occupied the world long ago! So, what is the truth? Today, let's talk about the super reproduction ability of cockroaches.

When it comes to reproductive capacity, we must first distinguish the types of cockroaches. In fact, cockroaches are not a type of insect, but a class of insects. In taxonomy, all insects belonging to the class Insecta and the order Blattodea can be called cockroaches. There are currently 4,300 known species, with more than 250 species in China. The two most common cockroaches in urban environments are the German cockroach and the American cockroach.

The German cockroach is generally about 1.5 cm long, with a yellowish-brown body and two black stripes on the pronotum, which is an easily identifiable feature. It is also commonly called "cockroach" or "northern cockroach."

The American cockroach can reach a length of more than 3.5 cm. Its body is usually reddish brown, with a light yellow pronotum and a pair of dark brown spots in the middle. Some people also call it "Da Qiang" or "Southern Cockroach".

So, can a cockroach reproduce 10 million offspring in a year? Generally speaking, small animals tend to have stronger reproductive capacity because they develop in a shorter time and mature faster. The reproductive capacity of the German cockroach is indeed much higher than that of the American cockroach, so let's take the German cockroach as an example, hereinafter referred to as Xiaoqiang.

Most insects, such as cockroaches, have chosen the R strategy of biological survival, which is to reproduce many offspring, exchanging quantity for survival probability. Each offspring is relatively fragile. Although many are born, many die. In contrast, the K strategy generally produces very few offspring, which are carefully nurtured. The number of offspring is small, but the survival rate is high. Primates, represented by humans, mostly adopt the K strategy.

Insects reproduce by laying eggs. To improve reproduction efficiency, female cockroaches only need to mate once to store sperm in their bodies for use whenever they want, and no longer need males. Insects usually leave their eggs alone after laying them. Crickets and mantises that lay their eggs in the soil or wrap them in foam are considered model mothers, but cockroaches are one step ahead. They use a special egg sheath to drag the eggs behind their buttocks. Generally, there are 16-40 eggs in an egg sheath, so cockroach mothers can carry these eggs everywhere until they hatch, thus preventing the eggs from being eaten by other animals.

In a suitable environment, the life span of an adult cockroach can reach nearly 200 days, and it can reproduce 5-8 generations. Each generation of larvae can become adults after more than a month, and then the cycle repeats... If we simply calculate theoretically, assuming that a German cockroach can lay 40 eggs per litter, half of which are female, then in a year, one cockroach will become 67,368,460. This is an astronomical number.

But this is only the ideal situation. In reality, there are many restrictions on the reproduction of cockroaches. Otherwise, the earth would not be able to accommodate so many cockroaches!

Cockroaches are at the bottom of the food chain and are fed by many animals. They are always in danger of losing their lives. Moreover, although they give birth to many cockroaches, not all of their offspring survive. For example, mantises, tiger beetles, and geckos all regard cockroaches as delicacies. Parasitic wasps lay eggs in cockroaches' bodies, and the larvae feed on cockroaches' flesh and blood after hatching. Cockroaches can die from accidentally ingesting cockroach medicine or crawling into cockroach houses while looking for food. Fungi and viruses can also kill cockroaches at any time. When food is scarce, cockroaches will even eat each other, and adult cockroaches will eat their own young as dry food.

Therefore, even in a breeding farm, a pair of German cockroaches can only produce about 20,000 to 30,000 offspring a year. Other large cockroaches reproduce even more slowly, with a pair of American cockroaches producing about 10,000 offspring a year. There is even a species of Cryptocercus spp. that reproduces very slowly, with baby cockroaches taking 5-6 years to grow up and needing to be raised by their parents for more than 3 years. Adult cockroaches secrete a milk-like liquid to feed the baby cockroaches.

In order to survive, Xiaoqiang also developed a set of survival skills, such as:

The cockroach has very long legs and runs very fast. It can move about 50 times its body length in one second. If humans could run that fast, its speed would be 300 kilometers per hour. The cockroach has very developed tentacles, many cold limbs, and caudal whiskers on its tail. These organs have very developed sense of touch, and the cockroach relies on them to sense changes in the surrounding situation in the dark. The antennae and caudal whiskers can also feel the subtle vibrations of the air around them, and infer whether there are other objects approaching. This is one of the reasons why it is difficult for us to hit it. The cockroach's body is flat, which allows it to squeeze its body into gaps, but the cockroach is not satisfied. The different parts of its body can "slide", which means that the cockroach can make itself flatter and squeeze into even the narrowest gap. And thanks to this structure, its body can absorb some of the force when it is impacted, so we may not be able to kill it in one hit when we hit it with slippers.

There are also rumors that cockroaches can still live for a long time after being beheaded. This is also true, because their important organs are concentrated in the abdomen, and the ganglia that control the limbs are in the chest. Cutting off their heads will not have much impact on the cockroach's ability to run around, except that it will lose sight and eat, and it can still live for a while.

In short, cockroaches do have a strong reproductive capacity, and they are able to spread all over the world. Although the claim that they reproduce 10 million per year is a bit exaggerated, they are well-deserved of the name "Xiao Qiang".

Author: Li Weiyang