Speaking of parasites, do you only think of its bad points? These cunning creatures live in the body of other organisms, grab nutrients from the host, and may even cause the death of the host, it is simply heinous! In fact, parasites are not that bad, and parasites are just their way of survival, just like beautiful butterflies suck nectar and cute penguins rely on fishing to survive.
Now let’s look at the bright side of parasites.
save endangered species
We know that to maintain ecological balance, the three roles of producers, consumers and decomposers are indispensable, but parasites also play an important role in it.
On shallow sea reefs, there are two groups of “slackers”, called limpets and sea anemones, living all year round. The limpet is an “old man” wearing a “bamboo hat”. When they find a reef they like, they stick to it with their abdomen and legs, and they can never move their nests for a lifetime; sea anemones are like a sunflower in full bloom, with countless growths. The tentacles don’t have long legs, so they can only cling to the rocks and wait for the food to arrive with their mouths wide open. Because both limpets and sea anemones like to live on the reef, the two sides often “meet by chance”, and then the limpet with a thin shell will be swallowed by the sea anemone. If this situation is not changed, limpets will become less and less, and at this time, trematode parasites play a role.
The ultimate hosts of trematode parasites are seabirds, but they prefer to lodge in bivalve molluscs when they are in the sea. When the bivalves are washed ashore, the trematodes will concentrate on the feet that the bivalves use to dig sand. In this way, the host’s feet seem to be stuck, unable to move anymore, and can only be left to the sea. The birds prey, and the trematode parasites enter the seabirds. The shells left by the bivalves will become the “new home” of the limpet, because this “new home” is usually on the shore, and sea anemones can only live in the water. After the limpet moves, there is no need to worry about being swallowed by neighbors.
The Japanese like to prey on a freshwater trout called Japanese char, which was once an endangered species due to overfishing and habitat destruction. To make matters worse, the rare charr always can’t compete with other fishes in large numbers when hunting, and they often can’t eat enough. At this time, nematode parasites helped a lot.
The nematode parasites live in the locust, and the nematode sucks the locust’s nutrition in a way that does not harm the locust’s life, and the two live in peace. But when nematodes want to reproduce, the problem comes, nematode larvae can only live in water, what should I do? The nematodes will run into the locust’s brain and manipulate the locust to dive into the water spontaneously. Then the nematodes will drill out of the locust’s body, enter the water to lay eggs, and leave the locust to fend for itself in the water. The locusts that “jump into the river” can be described as a free lunch that falls from the sky for the Japanese char in the river. Studies have shown that 60% of the food consumed by Japanese char in the river is these locusts that are manipulated by nematodes to jump into the river! Relying on these locusts, the fish survived one famine after another.
“Bodyguards” in living organisms
While the parasite sucks the host’s nutrients, it also bears the burden of protecting the host, because if the host “dies unexpectedly”, its life course will come to an abrupt end.
White-tailed deer that live in North America are protected by the parasite, and perhaps because of the parasite’s bodyguard, the white-tailed deer is one of the most widespread deer in the world. White-tailed deer are the ultimate host of a nematode-like parasite that can live in harmony with white-tailed deer without making them sick or dead. But when other cervids want to invade the habitat of white-tailed deer or attack it, the nematodes can infect other cervids, causing severe neurological disorders in the intruders, and even killing the intruders.
For hooked shrimp, internal parasites are also one of the tricks to save their lives. The hooked shrimp is a small crustacean that looks like a shrimp. They usually feed on decaying leaves, but when food is scarce, they will also appear cannibalistic. A researcher once discovered that in a river in Ireland, a foreign hook shrimp was accidentally invaded. Because of the “acclimatization” relationship, it could not eat the local rotting leaves, so it began to feed on the local hook shrimp , the number of local hook shrimp plummeted. Slowly, the ecology of the river was out of balance, as the number of predators decreased due to the decrease in the number of gamma, and the decayed leaves began to accumulate on the river bottom. At this time, the parasite in the gamma, the acanthocephala, came to the rescue. they. Acanthocephalus is a bit “picky eater”. They prefer to live in the body of the local hook shrimp. Once the host is suddenly changed, they will attack the new host. With the “help” of the acanthocephalus, the exotic gamma and the local gamma can finally “coexist peacefully”.
Nematode parasites live in locusts
Parasites are also of special help to humans. A research team at the University of Copenhagen in Denmark has discovered that Plasmodium, the parasite that causes malaria, can efficiently recognize cancer cells. Plasmodium invades cancer cells by binding to a polysaccharide molecule on the surface of cancer cells. The researchers extracted malaria proteins bound to polysaccharides in Plasmodium parasites and added a toxin substance that kills cells. When they added this recombinant compound to a culture dish of cancer cells, they found that it could quickly bind to cancer cells, integrate into cancer cells to release toxins, and kill cancer cells. Perhaps in the future, genetically recombined Plasmodium can become a “bodyguard” for cancer treatment.
big plan to save parasites
Parasites not only play an important role in the biosphere, but their harm is far less than imagined. According to data from the British Museum of Natural History, only 688 of the 19,951 species of parasites that have been discovered can cause human and animal diseases and are harmful. Parasites make up only 4% of the entire population! It can be seen that there are still many gaps in our understanding of parasites.
However, parasites are among the first organisms to be affected by extinctions. They often require several hosts to mature and reproduce, and their life cycle is interrupted as soon as one host disappears from its environment. Therefore, biologist Colin Carlson of Georgetown University in the United States and others proposed a global protection plan for parasites.
Protecting against parasites starts with understanding them. Compared with common zoologists, botanists, and microbiologists, there are very few parasite experts, and there are only a few websites that disseminate relevant parasite knowledge to the public, such as the American Long-term Ecological Research Network and the Australian National Ecological Observation Network. Moreover, humans have only identified about 10% of parasites at present, and know little about the remaining 90% of parasites, let alone relevant protective measures. Therefore, understanding the life cycle of parasites, and identifying their pros and cons, will be the first step in a conservation plan.
Legislation to protect endangered parasite species is an important part of conservation planning. Leeches are explicitly listed under the Convention on International Trade in Endangered Species of Wild Fauna and Flora, the first parasite to be protected as a species. Another parasite listed under the Endangered Species Act in the United States is the freshwater mussel that lives on the gills of fish for life. With the protection of the law, these parasites have finally obtained a “place of shelter.” Expanding the scope of inclusion of parasitic species in the Red List of Threatened Species will play an important role in the protection of parasites.
Finally, spreading the knowledge of parasites through websites, incorporating them into compulsory education courses, and publicizing and reporting through public media to get more people involved in the protection plan are the guarantees for the success of the plan. The British Freshwater Habitat Trust has launched a citizen science monitoring program for medicinal leeches, using bonuses to encourage citizens to participate in activities to discover and monitor the survival of leeches, and the information provided by citizens has provided great help for conservation actions.
Perhaps, it’s time to think about how to save parasites, rather than how to eliminate them.