Zero distance
Another major scientific contribution of Chinese scientists to the world
16 years of locust plague chasing murderers
It is hard to imagine that even today in the 21st century, the "locust plague", a disaster that seems to have raged on mankind for thousands of years, has not disappeared with the progress of human society and the highly developed technology.
Since the beginning of this year, locust plagues across the world have once again sounded the human alarm: “East Africa is experiencing the worst locust plague in 70 years”, “South Asian country India is hit by locust plagues again, and some cities are on alert.” “Locust plagues are approaching China’s Yunnan. Yellow-ridged bamboo locust disasters occur successively in various places"...The food security issue that concerns the foundation of human beings is directly threatened.
Locusts, these small insects the size of fingers, seem harmless to humans and animals. Why do they become disasters once they gather in groups? People were puzzled, and once thought that the locust attack was a "natural disaster." The cause of the locust disaster cannot be found, and it is hard to say that the job of human beings is practical.
The academician of the Chinese Academy of Sciences and researcher of the Institute of Zoology of the Chinese Academy of Sciences led a team of 16 years of follow-up research, and finally found the mystery of locust swarms. On August 12, this major scientific discovery was published in the top international academic journal Nature.
1 square kilometer locust swarm eats 35,000 people's rations in one day
When the locusts hit the sky and the earth, it will bring a scene that will cover the sky and the sun, and no grass will be left wherever it passes. For this reason, locust plagues are considered to be the three natural disasters in my country that are as famous as droughts and floods, which have caused serious agricultural and economic losses.
Among them, the two locust disasters, desert locust and migratory locust, are considered to be one of the main biological disasters of mankind.
Kangle told the China Youth Daily and China Youth Daily that the migratory locust is the most widely distributed locust in the world and a major agricultural pest in Africa, Asia, the Middle East and Australia. The historical records of our country for more than 2000 years show that there have been more than 800 large-scale locust plagues. Unlike migratory locusts, although desert locusts are only distributed in Africa, the Middle East, Southern Europe and South Asia, the records of their harm can be traced back more than 5,000 years.
To this day, this hazard continues. Ge Feng, a researcher at the Institute of Zoology, Chinese Academy of Sciences, said that an average of locust plagues occur around the world every five years.
Just from 2019 to June 2020, the desert locust outbreak spread from the Horn of Africa to southern Iran and the border between India and Pakistan to more than 20 countries and regions. According to the judgment of the Food and Agriculture Organization of the United Nations, the desert locust plague affected an area of more than 260,000 hectares, with a scale of once in 25 years. A locust swarm of 1 square kilometer can eat 35,000 people a day, and the food supply of 11.9 million people along the way is affected. Direct threat.
Ge Feng said that in recent years, Russia, North America and South America have also encountered local locusts. Worldwide, locust plagues still pose a major threat to agriculture, economy and the environment.
A century of unsolved scientific problems
Although the locust plague has been accompanied by the history of human development for a long time, people have less than a hundred years of scientific understanding of the cause of the locust plague.
In 1921, Yuvalov, an internationally renowned entomologist known as the "father of locust studies," discovered that migratory locusts can become plagues because locusts can transform from a low-density scattered type to a high-density group type. He was awarded the title of knight by the British Royal Family for his outstanding contributions to locust research.
To put it bluntly, scattered locusts, because of their low density, do not migrate, and can be considered harmless. Once the gregarious locusts form, they are likely to cause locust plagues.
So, how did the scattered locusts form locust swarms, and what is it that plays a key role?
In the past 80 years, scientists have put forward many hypotheses about this, such as food, breeding grounds, sexual maturity, cluster pheromone, climate and other hypotheses. However, which factor plays the main role, and what is the mystery and mechanism? No one can really make it clear.
It was not until the 1970s that scientists gradually realized that clustering pheromones may be the most critical factor in locust gathering.
Since then, after more than 50 years of continuous efforts by several generations of scientists, several compounds are considered to be the clustering pheromone of locusts. These pheromones have been named locust alcohol, locust phenol and so on.
"However, none of these compounds can meet all the criteria for clustering pheromone, especially there is no evidence of field population verification." Kangle said, for example, some are effective in the laboratory, but they are not effective in the field population verification. Some are effective against female locusts, but not against male locusts.
Who is the real culprit that caused the locusts to swarm? Chinese scientists have embarked on the road of "chasing the murderer."
It took 16 years to find the real culprit
In 2004, Kangle led the scientific research team to study the molecular mechanism of locust variant gene expression regulation and epigenetic regulation. After 16 years, they finally found a key chemical substance that lures destructive clusters of locusts-4-vinyl anisole (hereinafter referred to as 4VA).
"This is a compound with low release but very high biological activity." Kangle told reporters that the scientific research team found it in 35 compounds by analyzing the body surface and fecal volatiles of gregarious migratory locusts and scattered migratory locusts .
What’s interesting is that this chemical is very attractive to both gregarious migratory locusts or scattered migratory locusts, whether female migratory locusts or male migratory locusts, whether migratory locust larvae or adults. In response to changes in the population density of locusts, it increases as the population density increases.
The recreation team also discovered that only 4-5 scattered migratory locusts are needed to gather, and this kind of pheromone can be produced and released, which in turn promotes the formation of huge locust swarms.
"This shows that it has a very low induction threshold." Kang Le said. In other words, in the wild, it may only be necessary to gather locusts in a small area to release 4VA, and then attract more locusts to join in, making the locust team bigger and bigger.
Of course, this is only the result of the laboratory. Scientists have to go to the natural environment for further verification.
Researchers arranged the lure containing 4VA in the field. Through outdoor grass double selection and trapping experiments, it was proved that 4VA is very attractive to laboratory populations outdoors.
Furthermore, they deployed the lure core directly to Tianjin Beidagang, an area where locusts occur in the wild. The large-scale block experiment once again proved that 4VA can not only attract wild populations, but also is not affected by the background density of locusts in the natural environment.
So far, the recreation team judged that one of the "true culprits" that caused the locusts to swarm was 4VA.
In Kangle's view, this research is the first to comprehensively and fully assess the pheromone of migratory locust colonies from multiple levels including chemical analysis, behavior verification, neuroelectrophysiological recording, olfactory receptor identification, gene knockout, and field verification. After identification and verification, it was discovered and established that 4VA is the pheromone of migratory locusts, but other compounds reported in the past do not have all the conditions for the pheromone.
During the review of the article, three "Nature" reviewers spoke highly of the article. Two anonymous reviewers thought: "This research is an impressive, high-tech , In-depth research" "Research focuses on a very attractive biological problem, and has made very important progress in this field."
A transparent reviewer is an internationally renowned neurobiologist, academician of the National Academy of Sciences, and Rockefeller University professor Leslie Voshall. She clearly stated in her review comments: “This work has made an exciting He found a locust swarm pheromone molecule that people have been looking for for a long time. I give unconditional support. This outstanding work should be published in the journal Nature without any delay."
Green prevention and control of locust plague becomes possible
For a long time, people have mainly relied on large-scale spraying of chemical pesticides for the prevention and control of locust plagues. In an interview with reporters after the press conference, Kangle said that this study not only revealed the mystery of locust colonies, but more importantly, it made possible the green and sustainable prevention and control of locusts.
"We found that 4VA comes from plants eaten by locusts. It is very easy and cheap to synthesize 4VA artificially." Kangle said that the use of synthetic pheromone can monitor the dynamics of locust populations in the field for a long time and serve for forecasting; trapping can be designed The belt traps locusts, and uses chemical pesticides or biological agents to eliminate them in the trap belt, thus greatly reducing the use of chemical pesticides; antagonists can also be designed according to the structure of 4VA to prevent the aggregation of locusts.
According to him, researchers have also discovered specific receptors for 4VA among hundreds of locust olfactory receptors. After knocking out this receptor using gene editing technology, 4VA’s attraction to migratory locusts and migratory locusts The response behavior of 4VA is lost.
"This tells us that this mutant migratory locust can be cultivated and released into the wild for a long time, so that it is possible to establish a population of locusts that cannot live in groups in the hardest-hit areas. In this way, a certain number of locusts can be maintained in the wild. It also achieves the purpose of sustainable control, and organically combines environmental protection with pest control." Kangle said that the discovery of 4VA and its receptors will greatly change the countermeasures and technologies for locust control.
"This is a huge contribution made by Chinese scientists to international entomology and locust control." Xia Jingyuan, director of the Plant Production and Protection Department of the Food and Agriculture Organization of the United Nations, sent a congratulatory letter specifically for this achievement. He said that this is the first time scientists have truly confirmed the clustering pheromone of migratory locusts after 50 years of long exploration; the discovery of 4VA will greatly improve the prediction and control of locust plagues, and develop new locust plague control methods for people. Provide important clues.
From a simple review, we can see that humans’ understanding of locust swarms and disasters has experienced several important breakthroughs so far: The first is the famous locust transformation theory proposed by Yuvalov. After this theory was proposed, approximately The 10 most dangerous locusts have morphing phenomena. The second important breakthrough is the team led by British scientist Simpson, established in the 1990s, the behavioral discriminant mode and physiological characteristics of desert locust colony and diaspora. The third important breakthrough is the study of the molecular mechanism of the locust variant gene expression regulation and epigenetic regulation mechanism initiated by the Kangle academician team in 2004. Based on this, the team has now discovered the pheromone of migratory locust swarms. Reveal the mystery of migratory locust swarms.
Yang Huanming, academician of the Chinese Academy of Sciences and chairman of the Shenzhen BGI Institute of Genetics, said that this is another major scientific contribution of Chinese scientists to the world after participating in the Human Genome and Rice Genome Project.
China Youth Daily · China Youth Daily reporter Qiu Chenhui Source: China Youth Daily