2 March 2024

The term commensalism was first used to describe the hyena behavior. These fed while waiting for the lions to hunt their prey. And before taking advantage of leftovers and discarded food without trying too hard.

The process can involve from tiny species such as bacteria. Also, larger species like fish and sharks. Commensalism is currently very explicit in the fields of biology and ecology as we will see below.

Definition of commensalism in ecology and biology

Commensalism is a biological interaction between two species or individuals. In which one has a profit and the other stays in the same place.

It is a unidirectional connection where the one who benefits has a physical union with the one who initiates. But also there may be commensalism without having to be anchored, as is the case with scavengers.

Commensalism is a temporary bond that is created in two species. In such a way, that one clearly benefits while the other is treated with neutrality or indifference.

There are many cases of this type of interaction in nature, involving microorganisms, plants, animals, and both. Other examples of commensalism are epiphytes found in the trees. Or small fish that live anchored to the surface of the same but larger.

The types of relationships that can be interspecific within commensalism are:

  • The Predation: It is the link where an individual suffers because of the actions of the other.
  • Parasite: where the negative or detrimental result takes advantage of the host person.
  • Mutualism: positive relationship for both parties.
  • Competence: it is about the one who fights to be able to survive, and forces of both are matched.

Various characteristics of commensalism may develop, such as the following:

  • The interactions are biological
    • They interact in extensive or intricate ways.
    • Your relationship brings benefits
    • It has various consequences that are negative for interacting species.
    • Its affectation to organisms are involved in the relationship of operation according to biologists.
    • symbiosis occurs
    • Parasitism occurs

Includes organic beings between the existence of parasites and host

A relationship that exists between two different organisms that give up an object is known as commensalism. In this case, the parties do not destroy the other nor do they exploit it.

Therefore, the relationship is impartial. Mutualism is one of the other types of relationships that exist between organisms. Therefore, both parties destroy the circumstance. Parasitism is when one person injures another while taking advantage of her.

Despite the fact that the beneficial bacteria in our bodies are often referred to as commensalists. According to the studies carried out in this area, the relationship with the intestinal microbiota is mutualist and not commensal.

What types of commensalism are there?

There are various types of commensalism that establish a function of profit obtained. Next we will explain some of them:

The mechanical way in which an individual acts towards another it’s called phoresis. When the smallest organism attaches itself to the host in order to move, this is known as phoresis. Usually it is only temporary and does not cause any problems for the host.

When possible, the tenant can take advantage of the host’s food leftovers while moving safely and without spending a lot of energy.

Occurs when the creature uses the organism as a home taking advantage of him. Tenancy also goes further. It also describes how a different species or person works at home. Such as a specific rabbit hole or a hole used by other wildlife.

Occurs among bacteria. This particular form of commensalism takes place between two bacteria individuals. The second is intolerant of a particular metabolic byproduct. The first, however, intervenes at this point with his action.

And this makes it easier to tolerate the second before this modified product.

In addition to those mentioned, there may be others that refer to depending on your need.

  • Compulsory commensalism.
  • Facultative commensalism.


It is called compulsive or obligatory commensalism, when an individual must depend on another to survive. In short, it is a situation in which the benefited species survives for a short period of time without the other species. The chances of survival of the beneficiary species are significantly reduced when their mate is missing.

This type of commensalism occurs when certain species of mollusks and annelids they interact with a kind of chelicerate. Which is known as horseshoe crab or saucepan crab (Limulus). The surface of the horseshoe crab frequently has small attached invertebrates, which are obligate residents of the shell.


The individual in this situation could live without the other organism. However, doing it this way is easier and requires less energy. When the benefited species is capable of subsisting without the help of its symbiotic partner.

Using a trait from a different species is not necessary to survive.

Certain marine remoras can attach to the dorsal surfaces of sharks. they do it for eat leftover food that they have consumed In other words, they feed thanks to the work that the shark does to find food.

This type of phoresis of commensalism is permissible and of the Facultative branch. because the remora fish they can also survive without being attached to the shark.

For example, polar bear food scraps are beneficial to arctic wolves. In addition to making the wolf’s prey much easier to capture, this also reduces the energy required. But the wolf can live without the bear if it hunts on its own.

The existence of rodents, such as rats and mice, in domestic settings is another illustration that is closer to home. Because humans have given these tiny mammals food and safe places to rest, their populations have increased.

What is the difference between commensalism and mutualism?

Different differences can be evaluated between mutualism with the commensal. But we will evaluate at this moment the main ones.

  • Mutualism is a symbiotic bond. Where various organisms build together for mutual gain. Instead, likewise commensalism is a link between various organisms. But only one is profitable, leaving the other unscathed.
  • Mutualism is a symbiotic bond where all parties benefit. However, commensalism is an example of this cooperative relationship. In addition, one of the organisms is the one that benefits from the link, while the other is not. And she doesn’t do him any harm.
  • In a mutualistic relationship, both organisms depend on each other. Unlike commensalism, the two organisms are independent.
  • people in mutualism they are obliged to be in this kind of relationship. However, in commensalism, there is no such obligatory relationship between organisms.
  • In comparison tuning, commensalism your relationship works in the long run. But mutualism works in the short term.
  • The type of relationship between two or more people is called mutualism. As a result, everyone benefits of it. It is a link that exists between two or more individuals where one benefits and the other does not.

Examples of Commensalism in Biology

Below are some examples of commensalism in biology:

  • The shark and the ray: The shark feeds on the ray, but the remoras that live on the shark’s skin feed on the shark’s food scraps.
  • Birds and Mammals: Some birds, such as egrets, nest in trees where mammals, such as monkeys, also nest. Birds do not affect mammals, but they do benefit from having a safe place to nest.
  • The bird and the rhino: Some birds, such as crows, feed on the parasites that live on the rhino’s skin. The birds benefit from getting food while the rhino is not affected.
  • Orchids and trees: Orchids grow on the branches of trees without affecting them, while they benefit from receiving sunlight and nutrients that flow through the tree.
  • Bacteria and humans: Our bodies harbor many bacteria, some of which benefit from the relationship without negatively affecting us, such as the bacteria in our gut that help us digest food.
  • Fungi and plant roots: Mycorrhizal fungi live in the roots of plants without harming them, while they benefit by obtaining nutrients from the plant.
  • Ticks and animals: Ticks attach to the skin of animals and feed on their blood without killing them. Ticks benefit from the relationship, while animals are not affected.
  • Fish and sea anemones: Clownfish live among the tentacles of sea anemones unaffected by their venom, while anemones benefit from the fish’s presence by obtaining food and protection.
  • Birds and herbivorous mammals: Some birds, such as herons, feed on insects found on the skin of herbivorous mammals, such as cows. Birds benefit from the relationship, while mammals are not affected.
  • algae and fungi: Algae and fungi can form a symbiotic relationship called a lichen, in which the fungi provide protection and nutrients necessary for the algae to survive, while the algae provide food and oxygen for the fungus.

In the natural sciences there is amensalism, which is the opposite of commensalism. Thus, the relationship between two beings living in which one is harmed by the actions of the other. As when suffering the ravages of a parasite (parasitism) or being eaten by predators (predation).

people in a population benefit from the resources that are still available to people in another population. The commensal species are the ones that win.

Leave a Reply

Your email address will not be published. Required fields are marked *