Parasitism (Meaning and Explanation)

We explain what parasitism is, the types that exist and some examples. Also, what is social parasitism.

Parasitism - Parasite — Parasitism can occur throughout all phases of an organism's life.

What is parasitism?

Parasitism is a close biological relationship between two organisms of different species one called host (which receives or hosts) and another called parasite (which depends on the host to obtain some benefit). The parasite lives at the expense of its host, that is, it uses the host organism to meet its basic needs, which allows it to expand its own survival capacity. In most cases of parasitism, the host is harmed or suffers damage from the parasite at some point in the cycle.

parasitism can happen throughout all phases of an organism's life or only in specific periods. It may also happen that, since the parasite is still an organism, it hosts another specimen. These cases, in which the parasite hosts another parasite, are called hyperparasitism.

Types of parasitism

Mosquito - parasitism - parasite — Ectoparasites are found outside the host's body.

There are various ways to classify parasites, based on different criteria.

Depending on the location of the parasite in the host's body:
- The ectoparasites They are parasites that are found outside the host's body and take advantage of what they find in the outermost layer of the dermis and even manage to consume a little of their blood. For example, fleas and ticks.
- The endoparasites. They are the parasites that are found inside the host. Depending on the species of the parasite, some can cause mild damage and others can cause very serious damage. For example, worms that live in the intestines.
Depending on the level of dependence that the parasite has on the host:
- Facultative parasite They are those species of parasites that do not need the host to complete their life cycle since they are capable of another form of life in addition to the parasitic one.
- Obligate parasite They are those species of parasites that are totally dependent on their host at all stages of their life cycle and, therefore, cannot live without it.
- Accidental parasite. They are free-living organisms that, by mistake, reach the interior of an organism that is not their usual host, but despite this they manage to survive.
Depending on the length of time the parasite stays in its host:
- Temporary parasites. They are those that only require the host temporarily and to feed themselves.
- Periodic parasites They are those that need to spend one of the stages of their life cycle (egg, larva, juvenile or adult) inside the host, but then live freely.
- Permanent parasites. They are those that require the host throughout their life cycle in order to survive.

Examples of parasitism

Parasitism - Parasites - termites — Termites usually stay in trees and wood.

On our planet there are many examples of parasitism, among them, some of the most common are the following:

The mushrooms. There are species of fungi that are parasites. They usually live on the feet, nails or skin of animals and feed on keratin, an abundant protein in the epidermis.
The mites. They are a large group of ectoparasites, which usually live in the skin and feed on waste such as keratinocytes (dead cells) or secretions.
The mistletoes. They are parasitic plants that usually live in various species of trees in areas of Europe, America and Africa.
The termites. They are insects that usually stay in trees and in wood used for the construction of homes. They have a great capacity for destruction.
The bacteria. They form a diverse and extensive group. They are usually found in water and on land, so they enter the body through food and stay in the digestive system of animals.
The viruses. They are obligate parasites, since they cannot be considered living beings, and to carry out their functions they need to take advantage of the organism they invade. They frequently enter the body through the digestive or respiratory system.
The amoebas. They are endoparasites, which usually lodge in the intestines of animals. They feed on the host, so they can cause malnutrition and serious illness.
The worms. They tend to lodge in various parts of the host's body and can take away its nutrients.

Social parasitism refers to the type of association that some animal species make to obtain some benefit but it does not directly impact their organism or biology but rather benefits them in their social development. For example, some birds deposit their eggs in the nests of other species of birds, so that the latter can raise them.