Biological invasion is a topic that will always accompany human development, because as long as there is population movement and cross-border trade, it will provide opportunities for alien species to invade. There is a very large snail on the African continent, which is extremely fertile and has invaded Taiwan since the 1930s.
When it comes to the topic of biological invasion, we usually have images of creatures such as water hyacinth and Brazilian turtles in our minds, because these creatures have been written into the biology textbook of middle school as typical cases of biological invasion. In fact, in addition to these species that have been in our country or are being flooded in some parts of the country, there are also some "notorious" invasive species in other countries, such as the African giant snail, which will be introduced next.
We have the impression that a snail is a very petite mollusk that will melt by sprinkling a little salt on it. But friends who have seen the African snail know that this creature completely subverts the cognition of ordinary people. The average snail body length does not exceed 3 cm, while the body length of the African large snail is generally 7 to 8 cm, and the longest can reach 39 cm, which is more than the palm of an adult. The average snail weighs only a few grams, while the African large snail generally weighs hundreds of grams, and the largest weight reaches 900 grams, which is heavier than an ordinary turtle.
According to research, the African giant snail was originally distributed only on the African continent, but the rapid development of transportation between continents has also provided a way for these huge creatures to invade. Entomologists have introduced that African large snails generally achieve the purpose of leaving the african continent by laying their eggs in wood or agricultural products to be transported, and of course, there are many good people who bring them back to their countries as pets. As everyone knows, this area has caused a catastrophe of biological invasion, and there have been many famous cases of African large snail invasions in history.
Taiwan, China, introduced this snail in 1932, and the result is that in less than two decades, almost the entire Taiwan can see this snail, and it has caused a devastating impact on local agriculture. An American boy is documented to bring two large African snails back to Miami in 1966, and three years later they completely occupied all of Miami's watershed. Once the African giant snail adapts to the new environment and takes root, it will not be so easy to eradicate them, and the city of Miami in the United States has so far been working hard to limit the growth of the species, at a cost of several million dollars per year.
Having said all this, many friends must be wondering, where is the terrible thing about the African giant snail? The reason why an alien organism will pose a threat to the survival of local organisms and lead to the tragedy of biological invasion is nothing more than two basic conditions, one is environmental conditions, and the other is its own conditions. For the African big snail, neither of these conditions is a problem. Because they have strong environmental adaptability, even if there is not much food in one place and the living space is very narrow, they can still survive by eating other foods.
In addition, this creature has a terrifying ability to reproduce, and it has been found that they have four spawning opportunities every year, and they produce as many as 200 eggs each time, and the survival rate of these eggs is more than 90%. Juvenile African large snails grow very fast, and their sexual maturity is almost the shortest of all snail species, which lays the foundation for the spread of their populations. In fact, the existence of this creature was also found in mainland China as early as 2013, mainly in the southern region, and they are still not extinct.