（IC photo / 图）
When the school day came, many freshmen left their hometowns and went to distant cities to start university life. One side of the water and soil to support the other side, leaving their long-term living environment, it is inevitable to feel unaccustomed, so there are many exchange posts on social media about the differences between life in the north and the south.
Some students said that from the south to the north, they were extremely unaccustomed to the dry climate and the heavy taste of the meals, and they were not mentally prepared to bathe with others in the large bathhouse. Some students also shared that from the north to the south, every day experienced dampness and sweltering heat, roommates actually bathed every day, and did not know how to do without heating in winter.
It seems that the new students in the south and the north are very different in their living habits, and they need considerable time to adjust and adapt, but they unexpectedly reach a common view on one thing: the big cockroaches in the south are too scary, they are not only big, but also fly. Even people who have lived in the south for many years have a hard time calmly coping when cockroaches suddenly appear in front of them.
<h1 class="pgc-h-center-line" data-track="19" > why the southern cockroach is particularly large</h1>
Maybe it is really difficult for northerners to understand why someone who sees a cockroach will be scared to scream, or even cry, just like southerners are also difficult to understand, why some people see cockroaches, do not pick up the slippers at the first time, and shoot it to death. Without comparison, the cockroaches in the south and the north are basically two different species.
The most common type of northern cockroach is called the German cockroach, which is about 12 mm in size, has wings but cannot fly, and reproduces very quickly. The common species in the south is called the American cockroach, with an average length of about 4 cm (that is, 40 mm), which is two or three times larger than the size of the German cockroach, which can fly a distance with its wings, and is the largest of the common "semi-domestic" cockroaches.
In addition to the obvious difference in body shape, the living habits of the two are also different. American cockroaches have a mixed appetite and prefer to stay in dark and secluded environments, both indoors and outdoors. In contrast, German cockroaches are a bit "picky eaters", preferring food in residential households and willing to stay in a warm environment.
Originally born on the African continent, american cockroaches followed ships around the world with the onset of the Age of Discovery in the 16th century. For too long, scientists have tried to figure out why the cockroach has traveled from warm, humid Africa to a variety of climates around the world, but still survives smoothly.
In 2018, researchers at the Chinese Academy of Sciences deciphered the DNA of the American cockroach and found that the American cockroach has almost more DNA than all other insects, second only to the subspecies flying locust. Moreover, the genome of the American cockroach has 3.3 billion DNA bases, which is comparable to that of humans, and some of these genes have acquired superior survivability.
In general, chemical sensors made up of substances such as proteins can help insects perceive things around them. With 154 olfactory genes and 522 taste receptors, the American cockroach has the unique advantage of distinguishing between food and harmful things in their natural environment.
As the super foodies in the insect world, cockroaches can find something to fill their appetite anytime, anywhere. According to data released by the World Health Organization, cockroaches drink milk, nibble cheese, eat meat, especially chocolate, and have a preference for sugar and starch. At the same time, they also eat strange things, such as cardboard, books, shoe soles, their own molts, dead companions, and the nails of sleeping babies.
Researchers believe that it is the expansion of the cockroach gene family that has increased the plasticity of the sense of smell and taste for this species, and they have been able to adapt to each complex environment and spread their footprints around the world.
<h1 class="pgc-h-center-line" data-track="76" > can't play "coexistence"</h1>
Although american cockroaches can live outdoors, in some cases, they will take the initiative to enter the house and become people's "neighbors".
On the one hand, the weather, I don't know if everyone has noticed, after several days of heavy rain, the number of cockroaches in the house will always suddenly increase. Many cockroaches usually live near sewers and drainage ditches, they do not really swim, they will only float on the water, when the waterways and streets are full of rain, there is no way to go, they will run into people's homes to get together.
On the other hand, food, American cockroaches can eat a lot of things, but sometimes they eat too much outdoor materials, but also want to taste a little "taste of home". In addition to the items mentioned above, cockroaches will also stare at leather, plants, dirty clothes, cosmetics and soap, etc., and their appetite is beyond imagination.
Combined with the above two points, the most likely place in the home to meet with cockroaches is the kitchen, and other warm, humid places that can provide food sources, such as bathrooms and sewers, may also become cockroach territory.
I believe that many people have had such a life experience, when the lights are turned on in the middle of the night, they are suddenly startled by the big cockroaches on the walls of the room, or, in the dark, they go to the toilet, and vaguely hear the small sound of the things being turned over. If you don't want to be frightened in your daily life, the best way is to find out as soon as possible and solve it as soon as possible.
In fact, long before the cockroaches appeared, you can pay attention to some corners of the house in advance to see if there are any traces left by them. The first key inspection site is the kitchen, especially near the kitchen utensils, and the cabinet where the food seasoning is stored, and carefully observe whether there are some black, dense dots, which are most likely cockroach feces.
Second, you can easily recognize those brown oval cockroach egg sheaths, but it's hard to spot them. Because cockroaches generally hide their eggs in hidden places, such as the back of a large sofa, between the cracks in the walls, between the wardrobe and the corners of the walls, and so on.
There are rumors that when you find a cockroach egg, it means that you find a nest of cockroaches, which is true. A mature female cockroach can produce a new egg sheath every month in more than a year, and each egg sheath can hatch 8 to 12 cockroaches, and the growth rate is quite amazing.
The experience of life tells us that it is impossible to kill all the cockroaches in the house only through one means of killing, and more often, we only reduce the number of cockroaches to a more acceptable range through killing, and we can't see it and don't bother. But habits like keeping your house clean, disposing of kitchen waste in a timely manner, sealing food with packaging, and fixing leaky pipes can all help keep cockroaches from coming into your home.
Finally, and most importantly, when it is time to kill, kill immediately, whether it is slippers or spray, can kill only one.