It is said online that "riding a cockroach is as fast as taking the high-speed train". Is it true or false?

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The picture accompanying this article shows cockroaches

Where in China has the most high-speed railways? It may be Shandong , which has the longest total mileage, or the Beijing-Shanghai High-Speed ​​Railway , which has the largest passenger flow, or the Xuzhou-Xinjiang High-Speed ​​Railway , which has the longest route. Longer tracks mean more trains!

After hearing this, the Cantonese people raised their hands with pride and fear: We can also apply to fight .

A screenshot has been circulating online in recent days, which roughly says that cockroaches are the fastest six-legged animals, with a speed of up to 322 kilometers per hour - a speed comparable to that of high-speed trains ! In a sense, Guangdong has the most high-speed trains in the country, the world, and the universe!

I know this is a joke, but I still want to dispel a rumor. While striking at the perverted sense of hometown pride of some Guangdong friends, I also want to protect some Guangdong friends who are screaming.

N Mistakes of "Cockroaches Racing on High-Speed ​​Rail"

The conclusion that "cockroaches can run across high-speed rail" has several flaws. Let's talk about them one by one.

First of all, cockroaches can't run that fast .

In 1991, an American cockroach (a large cockroach more commonly seen in the south) at the University of California, Berkeley, set a world record of 5.4 kilometers per hour [1]. Have you ever seen a high-speed train that runs at 5.4 kilometers per hour? Have you ever seen a high-speed train pulled by a group of mules?

Besides, this is a world record after all. Not all cockroaches are so strong . After all, not everyone can run like Su Bingtian or Bolt. What’s more, the American cockroach is the big one in the cockroach family, and the German cockroach (a small cockroach that can be found in both the north and the south) runs even slower .

Common cockroaches in the home, small ones tend to run slower than big ones丨wikimedia commons

Secondly, the instantaneous speed does not mean the speed that can be maintained stable for a long time .

Friends who have cockroaches at home should have this experience: when you turn on the light when you get home at night, the cockroaches will whoosh from the open space into the gaps in the furniture - the speed at this moment is quite fast, but once they hide in the gaps, they will not move (and they may even gasp for breath from exhaustion for a while).

Our high-speed trains can run for hours at a time. How can a cockroach run for more than ten hours at a time ? Is there any cockroach that can run for only one minute at a time?

This tells us that we should not pursue momentary passion, stable output is more important!

Finally, cockroaches are not the fastest six-legged animals !

The subphylum Hexapoda includes the classes Insecta and Entomostomes. Here we will just discuss the fastest insects. According to the Guinness official website, the fastest insect is the Australian tiger beetle , which can move at a speed of up to 9 kilometers per hour[1]. Of course, this is also the instantaneous speed.

It is said that because the Australian tiger beetle moves so fast, it cannot see the objects around it clearly when running[2]. It is so powerful and cute.

I'm so fast, I'm also so confused丨youtube/Smithsonian Channel

Is the data in the screenshot wrong?

Judging from the subtitles on the screenshot, this data is obviously wrong.

Is it possible that the screenshot was taken out of context? Unfortunately, I didn't find the source of this video screenshot, so I can't verify it.

However, we can guess that the speed of "cockroach racing against high-speed train" may have used a common method: converting it into human size .

The above study says that the American cockroach can reach a maximum speed of 5.4 kilometers per hour, which is 1.5 meters per second, equivalent to 50 times its body length;

The speed mentioned in the screenshot is 322 kilometers per hour, which is 89 meters per second. 1/50 of 89 meters is 1.79 meters, which is equivalent to the height of a tall human.

It turns out that this speed is calculated based on the speed per second relative to the body length, and then applied to human height! Everything makes sense!

The English subtitle in the screenshot means "equivalent to 200 miles per hour". The "equivalent to" here should have a premise, and it is speculated that the screenshot missed it.

But there is still a problem: cockroaches crawl straight on the ground, so their moving distance and speed can indeed be compared with their body length; we humans generally do not crawl straight on the ground and move forward, so the method of converting cockroach speed to human speed is still quite problematic .

Unless you move like this | giphy

Rumors about cockroaches

The rumor that cockroaches can run faster than high-speed trains has been dispelled. There are many other sayings about cockroaches on this planet, let's talk about them together.

You see one, but there are 20,000 at home?

Not quite true

This is probably one of the most famous rumors about cockroaches: If you find a cockroach in your home, it means that there are 20,000 cockroaches living in your home in invisible corners.

the truth:

This data comes from a study conducted more than 30 years ago: American researchers placed cockroach sticky boards in the homes of low-income groups. One day later, there were an average of 42.3 cockroaches on each sticky board. After Jiangjiang Nianniang's calculations, the researchers believe that half of the houses have 13,000 cockroaches, and the worst case is 18,000 cockroaches - less than 20,000, we are saved!

Okay, let me comfort you.

"More than 30 years ago" and "low-income groups" are both relatively extreme situations. According to data from China in 2015, an average of 0.104 cockroaches can be caught in a room of 15 square meters per night . How many 15 square meters are there in your home?

Cockroach medicine no longer effective?

real

Sadly, cockroach medicine is becoming less and less effective.

Researchers in the United States conducted an experiment on three cockroach populations for six months to test their resistance to several common insecticides. The results showed that it was of no use and the cockroaches remained as numerous as before [3].

Other studies have further found that commonly used pesticides are effective against cockroaches born and raised in laboratories, but have little killing effect on real-life cockroaches . Even if they are caught, placed in a sealed container and sprayed directly with insecticide spray, the mortality rate of cockroaches does not reach 100% [4].

This is partly because cockroaches reproduce so quickly that genes that confer resistance to pesticides can be quickly passed on to the next generation and become increasingly stronger.

The above research subjects are all German cockroaches. To be on the safe side, we will assume that the same is applicable to American cockroaches.

If insecticides don't work, just clean your house well so that cockroaches can't live in it.

Do cockroaches love candy?

Not quite true

I have the impression that cockroaches love to eat sugar, so we would mix insecticide into the sugar and wait for them to take the bait.

the truth:

However, as the war between humans and cockroaches continues, the number of cockroaches that die because of their love of eating sugar is decreasing, and they cannot leave offspring. Those cockroaches that do not like eating sugar have gained survival and reproduction advantages. Now many cockroaches do not like eating sugar either , and sugar with added pesticides has lost its appeal to them.

Hmm... How about trying something salty? A salty-sweet perpetual motion machine!

Will cockroaches take revenge?

Fake

Some netizens said that you should kill all cockroaches, otherwise if they see their fellow cockroaches being killed by slippers, they will come to you with their families to seek revenge.

the truth:

Cockroaches are indeed intelligent among insects, but not so intelligent that they would feel the desire to avenge their fellows. In fact, the bodies of dead cockroaches emit specific pheromones composed of fatty acids, telling their fellows, "Don't come! You'll die!"

Even if a bunch of cockroaches come to you, what can they do? They are just living in your house without paying rent. Don't be afraid.

Can cockroaches come back to life?

Fake

Some people also say that the bodies of cockroaches that are killed by being slapped will mysteriously disappear and then make a comeback, earning them the title of "the indestructible cockroach."

the truth:

Most likely it’s because you didn’t kill the cockroach at all, and the cockroach just ran away on its own after it recovered .

Cockroaches are very good at transforming, changing from a standing height of 12 mm to a squashed height of 3 mm in just 300 to 800 milliseconds; and they can withstand vertical pressure of 900 times their body weight.

You think you have killed the cockroaches, but you may have just squashed them. The lethality of using a paper tube is even lower.

In addition, cockroaches can also pretend to be dead, even for several days. When you leave, it will get up, shake its head to wake itself up, and become a good roach again.

I am very distressed when writing this: I have summarized various rumors about cockroaches, some true and some false, and the conclusion that becomes clearer the more I debate is that I feel like there are a few cockroaches in my trouser legs now...

References

[1]https://www.guinnessworldrecords.com/world-records/70631-fastest-insect-on-land

[2]https://museumsvictoria.com.au/article/lunar-new-year-10-australian-tigers-cn/

[3] Fardisi M, Gondhalekar AD, Ashbrook AR, et al. Rapid evolutionary responses to insecticide resistance management interventions by the German cockroach (Blattella germanica L.)[J]. Scientific reports, 2019, 9(1): 1-10.

[4] Gordon JM, Eva MJ, Gaire S, et al. Common consumer residual insecticides lack efficacy against insecticide-susceptible and resistant populations of the German cockroach (Blattodea: Ectobiidae)[J]. Journal of Economic Entomology, 2024, 117(5): 2051-2059.

Author: Li Xiaokui

Editor: You Shiyou

This article comes from GuokrNature (ID: GuokrNature)

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