The first time a northern kid saw a flying cockroach, he cried for more than half an hour!!!

Audit expert: Li Weiyang

Well-known science writer

Cockroaches are magical creatures.

Since the term "Xiao Qiang" appeared in Stephen Chow's movie "Flirting Scholar", this nickname for cockroaches has spread like wildfire and reached every household. But to be honest, calling them "Xiao Qiang" is the most appropriate, because as the name suggests, they are really strong.

To be precise, the word cockroach does not refer to a single insect, but rather to thousands of species of the order Blattaria (excluding termites). The "cockroaches" that cause trouble in our daily lives mainly include the black-brown cockroach, the American cockroach, the German cockroach, the Japanese cockroach, and a few others, while the rest mostly live in the wild.

1

The north and south are different in size and strength

During evolution, although the appearance of cockroaches has not changed much, different species of cockroaches have gradually developed differences in body shape.

Taking my country as an example, the cockroaches in the north and the cockroaches in the south are not in the same league.

Most cockroaches in the south are American cockroaches, Australian cockroaches and brown-spotted cockroaches. They like warmth and humidity, are large in size, can fly, are widely distributed in tropical and subtropical regions, and are often found in cracks outdoors or indoors. They are the nightmare of many northern friends who have just arrived in the south.

Screenshot of netizens' comments

Source: Weibo

Because cockroaches in the south are so huge, there is even a spoof picture on the Internet saying "Guangdong cockroaches are very worried about you."

Source: Internet

The southern cockroaches are not only tougher than that. Because of their strong vitality, they will not die on the spot even if they are sprayed with insecticide. They can even escape with insecticide all over their bodies.

I even tried the cockroach gel bait and packed some away.

Source: Station B

As for cockroaches in the north, they are much inferior. Not only are they small in size, but they are also not resistant to pesticides and slippers.

Most northern cockroaches belong to the German cockroach, which is about the size of a melon seed or peanut. Although small in size, they are highly adaptable and widely distributed, and can be found in almost all human settlements around the world.

As long as there is a little suitable food, German cockroaches can basically survive and even reproduce. And compared with southern cockroaches such as American cockroaches, German cockroaches have another advantage, that is, they are more cold-resistant.

The German cockroach is not afraid of cold and has a high reproduction rate, making it the most difficult cockroach to control.

Common cockroach species

Source: Youchong.com

‍2

Xiaoqiang, the real strong man

If we trace the origin of cockroaches, they are much older than humans. Fossil evidence shows that the earliest members of the order Blattata appeared in the Carboniferous period more than 350 million years ago, which can be said to be one of the oldest members of the insect family.

Surprisingly, although cockroaches were born early, their appearance has not changed much after hundreds of millions of years of evolution. Even ordinary people without a background in biology can recognize the insect in the fossil at a glance. It is the "cockroach" that everyone hates in life.

In the long evolutionary process, they have been witnessing the changes of the world in an inconspicuous corner. They have a strong reproductive capacity. A female cockroach only mates once or twice in her life, and they can store sperm after mating and keep it for later use.

When cockroaches lay eggs, they wrap them in a special secretion, which becomes a brown hard shell when it dries, called an ootheca. They look like red beans, are resistant to high temperatures and dryness, and even ordinary pesticides cannot do anything to them. The ootheca protects the eggs inside from harm, which is one of the reasons why the cockroach population is so strong.

Cockroach egg case

Source: Tencent

What's even more amazing is that some cockroaches (such as the American cockroach) actually have a trick of "parthenogenesis"! When the living conditions are harsh or mating is impossible, these female cockroaches can also lay eggs that can hatch on their own. And these little cockroaches without a father are also female cockroaches, and their genetic information is exactly the same as that of the mother.

Cockroaches are not afraid of anything that comes their way, and they will eat anything that comes their way. Rotten meat, feces, leftovers, books, clothes, hair, soap, wires...most of the garbage produced by humans can be a feast for cockroaches.

In addition to their good appetite, they also have a strong motor nervous system. According to scientists, cockroaches can run 50 times their body length per second, which is equivalent to a human running at a speed of 330 kilometers per hour! Cockroaches also have a strong ability to balance, and can still run fast on uneven and bumpy surfaces. Inspired by this, scientists use cockroaches as the best sports model. For example, the design inspiration of the six-wheeled Mars rover was obtained from cockroaches.

3

Small but powerful uses

The Book of Zhou states: "The five medicines are plants, insects, stones and grains." Using insects as medicines to treat diseases has a history of more than 2,000 years in my country. Today, there are more than 300 species of medicinal insects in Chinese medicine, including ants, bees, cockroaches and other insects.

In traditional medicine and ethnic minority cultures, cockroaches are used to make medicines, and modern medicine has also used cockroach extracts to make medicines. The main active ingredient of the "Rehabilitation Solution" used to treat wounds and ulcers is the American cockroach extract. Cockroach extracts may even be used to treat AIDS.

Some studies have also found that there are three substances in cockroaches that can delay the death of human brain nerve cells and even regenerate new brain nerve cells. This means that in the future, humans may be able to use cockroaches to fight aging and treat Alzheimer's disease.

In addition to being used as medicine, cockroaches have other uses. In the eyes of pet breeders, they are excellent feed that can make tropical fishes colorful; in the eyes of engineering experts, they are the best sports models and have given radio experts many inspirations; in the eyes of cockroach lovers, they are pets that are low-key, quiet and docile; however, in the eyes of most people, although cockroaches have many uses, they are still not "good things".

4

Cockroach control strategy

There are many cockroach medicines on the market, which can be roughly divided into the following four categories:

Spray: It is effective in places with high cockroach density, but it is easy for cockroaches to develop drug resistance and pollute the environment.

Powder: The agent can easily enter the gap, but it is easy to become ineffective in a humid environment;

Aerosol: It can kill mosquitoes and flies, but it is dangerous to use and pollutes the environment. You need to open windows for ventilation after use.

Glue bait: safe and easy to use, high killing rate, not easy to produce drug resistance, no pollution to the environment, and can kill insects continuously.

For cockroaches, glue bait is like a delicacy mixed with poison. The Shanghai Center for Disease Control and Prevention once conducted a test on common glue bait products on the market. The results showed that the three mainstream ingredients - fipronil, sulfluramid and imidacloprid - had similar effects, with a 72-hour lethality rate of 90% to 100%.

9 different types of bait and their contents

Source: "Effects of 9 cockroach-killing gel baits on the killing of German cockroaches in the wild"

However, the little cockroaches are elusive and hard to spot. Where are they hiding? Pay attention! The following three places may be the worst-hit areas.

A place with plenty of food, usually the kitchen.

Source: Dingxiang Life Research Institute

Warm and humid places, around small appliances, sockets, stoves, radiators, etc.

Source: Dingxiang Life Research Institute

Places with many cracks and holes. Dead corners and gaps that are rarely cleaned may harbor cockroaches.

Source: Dingxiang Life Research Institute

In summary, in addition to buying the right medicine, you also need to know how to use it to achieve the desired effect. However, it should be noted that long-term use of the same medicine will cause cockroaches to develop drug resistance. It is recommended to rotate the use of different brands of cockroach medicine. In addition, the carcasses after killing must be handled in time, and the family must be cleaned regularly.

In short, knowing yourself and your enemy will ensure victory in every battle. Do a good job of daily hygiene and keep the environment clean, and you can say goodbye to cockroaches!

Source: Digital Beijing Science Center