Recently, the region of East and West Asia in Africa is now experiencing a very serious locust crisis, hundreds of billions of locusts are frantically nibbling on all edible plants and other crops on the way, and more than 11 million people in East Africa alone are facing food shortages caused by locusts.
How could a little locust leave so many people without food to eat? Let's take a look at it together.
Locust migration paths
<h1 class= "pgc-h-arrow-right" > terrible plague of locusts</h1>
Locusts, judging from the name, are the "emperor" of insects. The plague of locusts has been one of the representatives of the great catastrophe in human culture since ancient times, and this little locust was so terrible in the minds of the ancients that in many legends they are depicted as the devil representing famine, as recorded in the book of Revelation in the Bible.
In our country's ancient books, records of locust plagues also abound. The Spring and Autumn Period, the Book of Han, the Zizhi Tongjian, and so on all have records of locust plagues. The occurrence of locust plagues is related to the fundamentals of our agricultural power - food. Therefore, the emergence of locust plagues since ancient times has received great attention.
The reason why locusts are terrible is their strong reproductive ability, feeding speed and ability to migrate. In the case of the desert locusts, for example, their numbers increase exponentially when conditions are right: 20-fold after three months, 400-fold after six months, and 8,000-fold after nine months.
A one-square-kilometer locust colony can reach 80 million, and these locusts can eat the equivalent of 35,000 people's daily rations in a single day.
When an area has run out of food, locusts spread their wings in search of new feeding grounds. The speed at which locusts migrate is related to the speed of the wind, and they can fly over a distance of 150 kilometers in a day.
Locusts that cover the sky
<h1 class="pgc-h-arrow-right" >What kind of locust is it? </h1>
Some friends will ask: Aren't locusts just "grasshoppers" bouncing around in the garden? Why can a small grasshopper cause so much harm? How capable is it?
So let's first reveal the bottom of the locust. Locusts belong to the order Orthoptera and are close relatives of crickets and crickets. The common locusts around us are cotton locusts, flying locusts, rice locusts, negative locusts, sword horn locusts and so on.
Nymphs of negative locusts
In China, the main locust species that form a locust plague is the East Asian flying locust (Locusta migratoria), which is a subspecies of the locusta migratoria.
East Asian locusts live solitary
The locust that caused the plague in Africa was the Desert Locust (Schistocerca Gregaria), which looked a bit like a flying locust. At the time of the locust outbreak, the desert locust can fly to an altitude of about 2,000 meters above sea level and fly with the wind, and there have been reports that some desert locusts have crossed the Atlantic Ocean with the wind to reach the Caribbean.
Desert locust
In general, the harm caused by the desert locust is mainly in the west, north, east Africa, middle east, west Asian countries, Pakistan and India in Africa.
When the plague of desert locusts was at its worst, they spread over an area of more than 280,000 square kilometers, affecting 65 countries, accounting for about 20% of the world's land area and one-tenth of the world's population.
They also reached a maximum area of 16 million square kilometers during the recession, affecting 35 countries in Africa, the Near East and Southwest Asia.
Locusts like arid and hot environments, when drought makes the living space of locusts reduced, locust population becomes dense, bioinformatics will make locusts gather together, migrate in groups to find new places to feed, and locust plagues will also occur.
<h1 class = "pgc-h-arrow-right" > powerless predator</h1>
When a locust plague occurs, why can't the natural enemies of locusts eat them all?
There are many reasons, first of all, the locust plague occurs quickly, and the original insectivores are not enough to eat all the locusts. There was not enough time to breed more insectivores, and the locusts that had eaten all the local plants had already migrated to other places.
In addition, there are two types of these plagued locusts: diaspora and social, and these two types can be converted to each other.
The scientific research team led by Academician Kang Le of the Institute of Zoology of the Chinese Academy of Sciences found that when locusts become gregarious, phenylacetonitrile is produced in the body, which will make insectivorous birds have a strong dislike, and they do not like to prey on locusts anymore.
If hungry birds insist on preying on these social locusts, the locusts will also quickly convert phenylacetonitrile into toxic hydrocyanic acid, further avoiding predators.
Gregarious locusts produce chemicals that are disgusting to birds
<h1 class="pgc-h-arrow-right" > respond to locust infestation</h1>
Because of the great harm and difficulty of controlling locust plagues, for a long time in the history of our country people were powerless against locusts, believing that locusts were "god worms" and building temples to pray for blessings.
Since the Song Dynasty, people have begun to have a more scientific understanding of locust plagues, and have summarized methods to combat locust plagues, such as the method of singing gold to drive away, the method of catching and striking, the method of burning fire, the method of deep burial in ditches, the method of digging seeds (digging locust eggs), and the method of catching locusts with utensils when the temperature is low in the morning.
Ancient method of locust extermination, from the Qing Dynasty "Tips for Catching Locusts"
Modern people use airplanes to spray pesticides to kill locusts, in recent years, China uses unmanned aerial vehicles to spray matrine, neem, green zombie bacteria and other biological pesticides, not only the locust killing effect is ideal, the environment is also more friendly, the effect is far better than before.
There are also breeding chickens and ducks in Xinjiang and other places in China to control locust plagues, but this method is more suitable for locust species that have no migration habits and locusts (locust nymphs) that have not yet feathered, and are somewhat inadequate for flying locusts and desert locusts that can carry out long-distance migration.
At the same time, a small number of chickens and ducks is also a drop in the bucket for hundreds of thousands or even tens of millions of locusts per square kilometer.
Also, although locusts are rich in protein and can be used as a delicacy for us humans, the cost of catching and transporting them to the market is very high in the face of such rapidly migrating locust populations.
Often before people can bring their utensils to catch, swarms of locusts have eaten the fields and gone high.
However, the use of capture to deal with some small-scale locust plagues is very effective, both eliminating locusts and satisfying people's appetites.
Fried locusts and scorpions
Could this locust plague affect us?
Experts say that at present, the locust plague is less likely to affect China.
The low temperature in the high altitude is unbearable for locusts, so because of geographical barriers, locust swarms cannot fly over the Himalayas, and it is difficult to reach the territory of our country.
Most of the locust plagues that have formed in our country in history have been caused by east Asian flying locusts, and as we mentioned above, the cause of this locust plague is the desert locust produced in Africa, which has never caused a locust plague in our country.
Of course, we must not take this plague of locusts lightly, and we must prevent locusts or eggs from entering China's borders in other ways such as following people and things. At present, the relevant departments are closely following the development of this overseas locust plague, and we do not have to worry too much.