In nature there are symbiotic relationships between different organisms to achieve an end. There are relationships where one of the parties obtains very negative results, as in the cases of predation or parasitism. In other relationships, sometimes not even everyone involved knows that they are in a relationship. This is the case of commensalism.
In this article on our site we will discover the definition of commensalism, we will see what types exist and some examples of commensalism. Keep reading!
What is commensalism?
Commensalism in biology is defined as the relationship between two organisms of different species, where one of them benefits and the other gets nothing, neither positive nor negative. The result of the relationship for one of them is neutral.
Commensalism is a type of symbiosis that, unlike others, such as parasitism or predation, does not result in a negative outcome for any of the parties involved. On the other hand, the difference between mutualism and commensalism is that, in the first case, both individuals obtain benefits.
Commensalism in microbiology has also been extensively studied. For example, in a water column, the microorganisms that live closer to the surface usually benefit from sunlight, which is essential for their development. Their waste substances travel through the water column until they reach the bottom, where sunlight and oxygen are scarce. Here, anaerobic microorganisms (which do not need oxygen to live) take substances that arrive from the surface as a source of nutrients and energy.
Bottom microorganisms benefit from surface microorganisms, while surface microorganisms get nothing. It is worth noting here the term amensalism Contrary to commensalism, in these relationships one of the parties is harmed while the other remains unchanged. This is the case of certain fungi such as Penicillium, which secrete antibiotics preventing the proliferation of bacteria.
Types of commensalism
When studying the relationships established between living beings, the great variety that exists forces us to subclassify commensalism into three different types, since there is no single way in which animals benefit from mutualism:
- Phoresis: the term phoresis refers to the relationship established between two species when one of them transports the other. In most cases, the transporter is not even aware that he is transporting another living being.
- Inquilinism: Inquilinism occurs when one species occupies the body of another to live, without causing any type of nuisance.
- Metabiosis: This type of commensalism is very common in the animal kingdom. It occurs when one species feeds on the waste of another, such as its feces or its own decomposing body or the case of anaerobic microorganisms that we discussed earlier.
Examples of commensalism
There are many commensal relationships in the animal kingdom. Many of these relationships occur between members of this kingdom with organisms of the plant kingdom. Some of these examples are:
1. Commensalism between opiliones and ants
In certain areas of Argentina, where this relationship has been discovered, the climate is very dry, which makes it impossible for opiliones, some social animals belonging to the order of arachnids. Anthills offer a more humid microclimate that favors opiliones. These live inside the anthills without causing the ants benefits or harm.
two. Commensalism between the Iron Island giant lizard (Gallotia simonyi) and the yellow-legged gull (Larus michahellis)
The non-fledged chicks of this gull species regurgitate part of their food when they feel too full or are disturbed by other adult gulls. The giant lizard then benefits by feeding on the insects regurgitated by the gull chick.
3. Commensalism between Chaffinches (Fringilla coelebs) and Black Starlings (Sturnus unicolor)
Starlings, in León, northwestern Spain, feed on blackberries in summer. When they eat they drop seeds to the ground or on the leaves of the mulberry tree. The finches, granivorous animals, search between the leaves and the ground for the seeds discarded by the starlings, even taking them directly from the starlings' faeces.
4. Commensalism between flies and ham mites
This is a very curious example of phoresis In the ham dryers, they sometimes have problems with mites, which bite the ham and invalidate it for sale. The hams are hanging from the ceiling so the invasion by mites would seem complicated. These animals mount on the flies that visit the hams. When they get to a ham, the mites get off the fly. The flies get nothing, they don't even realize they are carrying mites.
5. Commensalism between birds and trees
Birds that nest in trees, obtain from it protection and a place to build their nest. Trees do not get anything, neither positive nor negative.
