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What is commensalism: definition and examples

Have you ever heard of commensalism? Surely yes, or at least you will know that it is a type of relationship or interaction between two living beings. We normally see it with animals, but it also occurs in plants, even humans.

In this AgroCorrn article we will explain what commensalism is with a simple definition, the types that exist and, in addition, we will put some examples of commensalism to solve all the doubts that may remain or arise.

You may also be interested in: Mutualism: definition and examples
  1. Types of interspecific relationships
  2. What is commensalism – definition
  3. Types of commensalism
  4. Examples of commensalism

Types of interspecific relationships

Before addressing the specific topic of commensalism, let’s first quickly name some of the types of interspecific relationships that occur in nature:

  • Predation (cheetah-gazelle): relationship in which one individual loses by the action of the other, that is, one of them dies to be food for the other, like the gazelle in the example indicated.
  • Parasitism (dog – flea): use that is negative or harmful to the host individual.
  • Mutualism (bees – flowers): positive relationship for both parties.
  • Competition (lion – leopard): relationship in which they have to fight to survive, it occurs when the forces of both are equal and one does not suppose to be a predator of the other.

If you want to learn more about interspecific relationships, their types and examples , enter this other post from AgroCorrn. In addition, you may also be interested in learning about the relationships between individuals of the same species and, for this, we recommend this other article on What are intraspecific relationships with examples .

What is commensalism – definition

Commensalism is a type of biological interaction that occurs between two species or individuals, in which one of them benefits and the other is not harmed but not benefited, colloquially said “it stays as it was”. If we transfer it to human beings and to name a daily action when we are hot, if a person is hot and fans and there is another person next to him with heat as well, this takes advantage of the movement of air generated by the first person with his fan , something that does not affect it for good or bad.

In other words , commensalism is a unidirectional relationship , where the individual who benefits is usually physically attached to the first individual, although commensalism also occurs without being anchored, as in the case of scavengers. Here you can learn more about What are scavengers .

Types of commensalism

The types of commensalism are established according to the benefit obtained. We will explain each of them below:


The term phoresis is given to the mechanical use of one individual with respect to the other, that is, the phoresis occurs when the smallest individual (usually) attaches to the host to move. It generally does not reverse any problems for the host, and it is also temporary. The tenant moves safely, without wasting energy and can sometimes take advantage of the host’s food remains.


It occurs when the individual takes advantage of the body in a way that serves as a “home”. In addition, tenancy goes further, it also defines the occupation of the home of another species or individual, as a burrow used by another animal other than a rabbit.

Chemical commensalism

It occurs between bacteria, to be exact and to be clear, this type of commensalism occurs between two specific bacteria. The second does not tolerate a certain product of a metabolic process, but at this time the first intervenes, through its action it facilitates the tolerance of the second to this modified product.

If we stop to define more types of commensalism, we can refer to those that are given according to need.

  • Mandatory: the individual needs the other for their survival.
  • Optional: in this case the individual could survive without the other organism but in this way it is easier and with less energy expenditure.

Examples of commensalism

Next, we present in the table in the image below the examples of each type of commensalism so that in this way you can visualize what was explained previously more clearly.

In the case of the example of the interspecific relationship known as foresis and, more specifically, in the case between shark and remoras, it would also be valid for the case of the facultative type, since they could survive independently, but it is much easier for them to do so. with the support of such a powerful animal.

After reading this AgroCorrn article and complementing it with others already published on our page, we hope that it has served to resolve any doubts that may exist about it.

If you want to read more articles similar to What is commensalism: definition and examples , we recommend that you enter our Biology category .

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