What is Parasitic Nutrition? Explain it

Parasitic Nutrition is a type of heterotrophic nutrition in which an organism (known as a parasite) lives on the surface of another creature’s body or inside it (known as a host). The parasite gets its nutrients directly from the host’s body. 

Because these parasites rely on their hosts for nutrition, this symbiotic relationship is frequently portrayed as damaging to the host.

What is Parasitic Nutrition?

Parasitic nutrition is a type of nutrition in which organisms live on or inside their hosts’ bodies and feed off of them.

The parasite that obtains the food is known as a parasite and the organism from whose body the food is taken is known as the host-parasite.

Parasites are organisms that live inside or on other organisms and feed on their hosts’ waste. The majority of parasites are harmful to the hosts’ health, and can even kill them in some situations.

Several fungi, bacteria, a few plants like Cuscuta, and animals like plasmodium use a parasitic mode of sustenance.


Parasitism is a type of symbiosis in which a parasite and its host have a tight and long-term biological relationship. Parasites, unlike saprotrophs, feed on living hosts, however some parasitic fungi, for example, may continue to feed on dead hosts. 

Unlike commensalism and mutualism, parasitism causes harm to the host by either feeding on it or devouring some of its food, as in the case of intestinal parasites. Because parasites interact with other animals, they can easily act as disease vectors and spread infections. 

 Predation is not a symbiosis by definition because the connection is brief, although parasites have been described as “predators that consume prey in units of less than one” by entomologist E. O. Wilson. 

There are numerous possible strategies within that scope. Parasites are classified by taxonomists into a range of overlapping schemes based on their interactions with their hosts and their sometimes complicated life cycles. 

A facultative parasite does not rely on the host to complete its life cycle, whereas an obligatory parasite does. “Direct” life-cycles involve only one host; “indirect” life-cycles involve a definitive host (where the parasite reproduces sexually) and at least one intermediate host. 

An endoparasite resides inside the host’s body, whereas an ectoparasite dwells on the surface of the host. 

Mesoparasites, such as copepods, penetrate an opening in the host’s body and become partially entrenched. 

Some parasites are generalists, feeding on a variety of hosts, while many parasites, including the vast majority of protozoans and helminths that parasitize mammals, are specialists with a narrow host range. 

Microparasites and macroparasites were classified as microparasites and macroparasites in an early functional separation of parasites. To analyse the population movements of the host-parasite groupings, each of them was allocated a mathematical model. 

Microparasites are bacteria and viruses that may replicate and complete their life cycle within the host. 

Multicellular organisms that reproduce and complete their life cycle outside of or on the host’s body are known as macroparasites.

How ecology benefits from parasites?

Until the twenty-first century, parasitism and parasite evolution was studied by parasitologists, rather than ecologists or evolutionary biologists, in a science dominated by medicine. 

Even though parasite-host interactions were ecological and crucial in evolution, the history of parasitology resulted in a “takeover of parasitism by parasitologists,” according to evolutionary ecologist Robert Poulin, leading ecologists to overlook the field.

Although parasites are usually thought to be harmful, eliminating all parasites would be counterproductive. Parasites are responsible for at least half of life’s diversity; they play critical ecological roles; and without parasites, organisms may turn to asexual reproduction, reducing the range of features that sexual reproduction brings. 

Parasites allow for the exchange of genetic material across species, allowing for evolutionary change. To complete their life cycles, many parasites require many hosts of various species and rely on predator-prey or other stable ecological interactions to move from one host to the next. As a result, the presence of parasites implies a healthy ecology. 

The California condor louse, Colpocephalum californici, is an ectoparasite that has become a well-known conservation issue. The Californian condor was rescued by a large-scale, high-cost captive breeding operation in the United States. 

It was home to a louse that solely ate it. To preserve the condors in the best possible health, any lice identified were “deliberately eliminated” during the programme.

 As a result, one species, the condor, was saved and released back into the wild, while another, the parasite, died off. 

Even though parasites are frequently absent from portrayals of food webs, they normally occupy the top spot. Parasites can act as keystone species, allowing competing species to coexist while lowering the dominance of superior competitors.

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