It’s cockroach season again! Why can’t we kill or eradicate these “little cockroaches”?

The higher the temperature, the faster cockroaches reproduce. With hot weather appearing all over the country, it is the season for cockroaches to appear again.

Cockroaches live in dark corners, not only chewing up objects and contaminating food, but also spreading diseases such as dysentery and typhoid fever. As one of the "four pests" that everyone hates (the other three are mosquitoes, flies, and rats), cockroaches are called "the indestructible cockroaches."

We have tried pesticides, sprays, sticky insect boards, etc., but the "cockroaches" are getting more and more. They can't be killed or eradicated, and this summer is destined to make many people worry.

No.01

There are differences between cockroaches in the north and south

Cockroaches belong to the order Blattodea of ​​the class Insecta. Their scientific name is Blatta. In the south, they are also called "oil-stealing women". "蠊" is a special word, mainly used as a formal name for cockroaches, which shows how big its "face" is.

Cockroach, one of the “four pests” (Source: Global Information Network)

Like mice, cockroaches are typical "night owls" , hiding in the corners of wardrobes, cupboards, sewers, power strips and other places during the day , and coming out to look for food at night. They also like warm places, which is one of the reasons why the kitchen has become a disaster area. What's worse, cockroaches hide in computer motherboards and printers. When the machine is turned on, their bodies act as conductors, causing short circuits and damaging the machine (mainly northern cockroaches).

Due to different climates and eating habits, cockroaches in southern and northern China are different in shape and habits. Cockroaches living in the north are mainly German cockroaches, which are small in size, with an adult body length of more than 1 cm, short wings but cannot fly; cockroaches living in the south are mainly American cockroaches and Australian cockroaches, which are relatively large in size, with an adult body length of more than 3 cm, wings and can fly short distances. If the German cockroach in the north is compared to a newly hatched chick, then the American cockroach and Australian cockroach in the south are adult hens. Therefore, many northerners are often frightened by the large and flying cockroaches when they first arrive in the south.

The difference between northern and southern cockroaches (Source: Cockroach Network)

There are also differences in the way cockroaches in the north and south raise their young. After cockroaches mate, a bean-pod-shaped egg sheath will grow at the end of the female cockroach's tail. This special gelatinous sac produced by secretions is slippery, hard, and waterproof. Each female cockroach produces between 10 and 100 egg sheaths. After the German cockroach lays its eggs in the egg sheath, it will drag it with it until all the larvae are hatched before throwing it away. This "responsible" attitude leads to a high survival rate for the larvae, making it more difficult to kill cockroaches in the north. After the American cockroach and the Australian cockroach lay their eggs in the egg sheath, they find a corner and throw it away. This "irresponsible" attitude makes them more capable of survival. Studies have shown that the American cockroach can live for more than half a month without drinking water (eating very little food), and can live for more than a month without eating food (drinking appropriate water).

Egg sheaths of different cockroaches (Source: Global Information Network)

No.02

Life is more tenacious than you can imagine

Cockroaches are not only one of the oldest animals in the world, but also the most tenacious animals in the world. Cockroaches have lived on Earth as far back as 350 million years ago, earlier than the appearance of dinosaurs. They successfully escaped the asteroid collision that caused the extinction of dinosaurs and are still alive today, almost everywhere in the world. There are more than 6,000 species, mostly wild, with fewer domestic species. The main cockroaches in China include German cockroaches, American cockroaches, and Australian cockroaches.

There are three main reasons why cockroaches are impossible to kill or exterminate and have such tenacious vitality: they are omnivorous, have strong reproductive ability, and have special body shape and organs.

Omnivory is the most prominent feature of cockroaches. In addition to meat, vegetables, fruits, and beverages eaten by humans, cockroaches also eat leather, soap, glue, paper, food residues, animal excrement, etc. Eating paper is its most special hobby, so study rooms, libraries, etc. must pay attention to regular cockroach disinfection.

Strong reproductive capacity is a common feature of the "four pests", and it is more profound in cockroaches. Cockroaches have a strong reproductive capacity beyond imagination: they can produce several or dozens of eggs after mating once. They lay forty or fifty eggs each time, and can produce hundreds of cockroaches in their lifetime. What's more, some female cockroaches can lay eggs and hatch offspring without mating with male cockroaches. The scientific name of this phenomenon is "parthenogenesis", which mainly exists in some more primitive animals, such as hammerhead sharks, aphids, etc. The fact that cockroaches have the ability of parthenogenesis means that it is more difficult to eliminate them. Therefore, the saying that "if you find a cockroach at home, it means there are at least hundreds of cockroaches at home" is scientifically based.

Cockroaches hatch through egg sheaths (Photo source: Cockroach Network)

The unique body shape and organs are another reason for the strong vitality of cockroaches. This mainly includes two aspects: one is the flat body shape and hard bones; the other is the special respiratory organs.

The flat body shape allows cockroaches to enter very narrow places, such as the gaps in cabinets and the sockets of power strips. It is convenient for hiding and escaping. The hard exoskeleton of cockroaches can protect them from external impacts. The simplest example is that when you step on a cockroach, it may appear to be dead, but it is actually still alive. If you don't deal with it in time, it will escape.

Unlike other animals, cockroaches breathe through spiracles. Spiracles are small holes on their bodies. This shows that cockroaches do not need high blood pressure, their blood vessel network does not need to be too large, and their heads are not as important as those of other animals. Therefore, when the cockroach's head is chopped off, the blood in the wound coagulates quickly, and the spiracles on its body can still breathe, and it will not really die until a week later. In other words, although headless cockroaches cannot run within a week, their reproduction and other functions still exist. The reason they die after a week is that they cannot eat and are starved to death.

The pores on a cockroach are called spiracles (Image source: Cockroach Network)

NO.03

How to scientifically kill cockroaches

Many people are at a loss as to what to do about the indestructible cockroaches. There are many ways to kill cockroaches online, such as using cockroach baits and sprays. At first, the effect seems good, but after a while, cockroaches appear again. This goes on and on, which is exhausting and frustrating.

Picture of killing cockroaches with cockroach bait (Source: Life Common Sense website)

If there are a lot of cockroaches in your home, especially when they appear in the kitchen and other places during the day, it is recommended to find a professional pest control company to eliminate them.

If there are few cockroaches in your home, it is recommended to clean the cupboards and wardrobes, fill small gaps, and use cockroach baits to disinfect cockroaches. Whether you hire a professional company or disinfect cockroaches yourself, you must pay attention to the cleanliness of the room. A clean house is the key to keeping cockroaches away. Especially in summer, wash dishes and clean up food in time after meals; take out the garbage once or twice a day, because the garbage can is a happy place for cockroaches.

In addition, the most critical method to eliminate cockroaches is to remove the egg case. However, the egg case is small and hard, so it is not easy to remove. For example, after a cockroach is crushed to death with a shoe, it may carry the cockroach egg case in its body, and drugs cannot kill the eggs in the egg case. Putting dead cockroaches in the trash is equivalent to releasing the larvae. The correct way is to burn the cockroach corpse with fire to prevent the egg case from hatching.

In short, once cockroaches appear in the room, we must not take them lightly. In the summer when the reproduction capacity is extremely fast, we should pay more attention to them and use scientific methods to eliminate them. Who says it is an indestructible "cockroach"?

References:

1. "Cockroach Control: The Harm, Morphological Characteristics and Life History of Cockroaches", by Jiang Zhikuan and Wu Guanghua, "Chinese Hygiene Insecticides and Equipment", Issue 1, 2009

2. "Study on the Biological Characteristics and Medicinal Value of American Cockroach", by Feng Linlin and Zhang Zhongxian, Journal of Capital Normal University (Natural Science Edition), July 2015

3. "Fossil cockroaches of China", by Lin Qibin, Acta Entomologica Sinica, No. 21, 1980

Author: Wei Deyong, member of Shenzhen Writers Association, Guangdong