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Mutualism vs Commensalism – Similarities and Differences

Mutualism vs Commensalism

Mutualism and commensalism are closely related to each other as they are both types of symbiosis.

Symbiosis is the association of multiple organisms with one another, it covers all kinds of associations, i.e, associations that are mutually beneficially, partially beneficial, or harmful for the interacting organisms.

The main difference between the two is that in mutualism both organisms get benefit from one another whereas, in commensalism, only one of the interacting organisms gets all the benefits. The other one is neither benefited nor harmed from this association. 

What are Mutualism and Commensalism?

Both mutualism and commensalism are different types of symbiosis. Symbiosis is the interaction process between multiple types of organisms belonging to two completely different species.

Depending on the outcome of the interactions, the association can be:

  • Positive (mutually beneficial for both parties)
  • Negative (benefits one party at the expense of the other), or
  • Neutral (beneficial to one but insignificant to the other).

Based on the above potential outcomes, symbiosis can be of various types:

  • Mutualism – Positive. Both species mutually benefit.
  • Commensalism – Negative. One party benefits at the expense of the other.
  • Predation – Negative. One party benefits and the other party dies.
  • Competitiveness – Negative. Both parties compete for limited rezsources.
  • Parasitic – Negative. One party benefits by living with, on, or in the other, at the other’s expense.

Read Also: Mutualism vs Symbiosis

What is Mutualism?

Mutualism is the interaction between multiple organisms belonging to two different species where both of the different species types get benefitted and this interaction helps in increasing their rates of survival. 

Mutualism can be of various types:

  • Facultative Mutualism – Two species benefit from each other but do not depend upon each other.
  • Obligate Mutualism – Two species are highly dependent on one another for mutual benefit.
  • Trophic Mutualism – Two species transfer resources and energy between one another for mutual benefit.
  • Defensive mutualism – One species receives protection from predators in exchange for shelter, food, or another good or service.
  • Dispersive Mutualism – Animals that disperse pollen for plants so they can reproduce.

Read Also: 15 Commensalism Examples

What is Commensialism?

Commensalism is another kind of symbiosis in which a particular kind of interaction develops between two organisms of different species where only one of the engaging parties benefits however the other organism is not impacted by any means by this association. 

This means one kind of organism gains some benefits from the other one but the latter organism is not positively or negatively impacted by this interaction.

Commensalism can be of various types:

  • Inquilinism – Living in the next, burrow, or home of another animal.
  • Metabiosis – One animal is dependent on another for the preparation of an environment in which they can live.
  • Phoresy – One animal travels on another animal.

Similarities between Commensalism and Mutualism 

Both commensalism and mutualism are types of symbiosis and hence are closely related to each other. 

  • Both involve the engagement of multiple organisms that comes from totally different species background.
  • The interaction will be beneficial to at least one of the engaging organisms. 
  • The interactions deal with the aspect of food procuring, shelter, transport, defense, and support.

Differences between Commensalism and Mutualism

Mutualism and commensalism differ in the following ways:

  • In mutualism, both the engaging parties will benefit and hence are dependent on each other. In commensalism, only one party benefits.
  • In mutualism, Both organisms are dependent on each other. In commensalism, one organism is partially dependent for its survival on the other organism. However, the latter organism has no dependency on the former organism. Their absence or presence doesn’t make any difference in their quality of life.
  • In mutualism, both organisms can face an existential crisis if the other disappears. In commensalism, only the dependent organism will face problems in its survival in the absence of the other organism.

Prominent Examples of Mutualism

1. Oxpeckers and Larger Mammals

Type: Facultative and Defensive Mutualism

Oxpeckers are birds that feed on insects and parasites which toils around or grows on the body of larger mammals like hippopotamus, rhinoceros, and oxen.

This is something of great help for mammals as they often struggle to get rid of such parasitic activity on their body which often leads to many forms of diseases in the future. 

The birds depend on them for food while the animals get their body cleansed by these birds. Moreover, the oxpeckers also alert these large animals of any kind of approaching danger in advance. This is important to these mammals because these larger-sized animals often suffer from poor eyesight.  

2. Bees and Flowers

Type: Dispersive Mutualism

Flowers provide bees with nectar. The bees, after consumption of the nectar, carry off the pollen from that flower to a distantly located flower of a similar plant. 

This further leads to pollination, which only happens because the bees act as the carrier of pollen. Otherwise, the pollen wouldn’t have traveled so far. 

The flowers of different plants are even known to develop special traits like having sweeter nectar than other flowers or having a stronger scent which further gives them a competitive edge in attracting pollinators. 

Prominent Examples of Commensalism

1. Golden Jackals and Tigers

Type: Metabiosis

Golden jackals are often expelled from their packs. When they are on their own they find it hard to hunt for prey. This is because they generally hunt in packs or at least in pairs. 

So, to make life easier, they form a commensal relationship with tigers. They trail tigers and follow them around in their quest to hunt for prey.

Once the tigers have successfully hunted and feasted on that food, the jackals are known to feed on the remains of the prey.

2. Birds and Army Ants

Type: Metabiosis

Even though birds and ants have got the relation of predators and prey, in certain instances birds are found to exhibit a commensal relationship with ants, particularly army ants.

The birds follow the trail of the army ants which often leads them towards dead insects or sometimes near the nests of living insects, which then act as a viable food resource for the bird. 

The presence or absence of the birds doesn’t directly make any difference for the ants. However, the birds benefit from the ants.

Birds avoid feeding on the ants as they can attack the birds in huge numbers and can inflict some painful damage to their body. 


Commensalism and mutualism are not contradictory associations, they are like two different branches of the same tree.

They share deep relations. Both of these associations enhance the survival rates of the organisms out in the wild. It is just that in mutualism, both interacting parties are benefited from one another, whereas in commensalism, only one of the interacting parties benefits. The association doesn’t affect the other party in any way.

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