We explain what commensalism is and its differences from mutualism. Also, examples and how it develops in the desert.
What is commensalism?
Commensalism is known as a specific type of interspecific biological interaction, that is, interaction between individuals of different species, characterized by the benefit of only one of those involved without the other party receiving any type of damage or harm.
The term commensalism It comes from the Latin cum mensa, which translates as “sharing the table.” and was originally used for those cases in which one animal fed on the remains of another's food, as do scavenger animals, which wait for the hunter to finish feeding. However, there are many other cases that can be understood as commensalism, such as:
- Foresis It occurs when the diner uses another species to transport himself from one place to another.
- tenantism In this case the commensal finds accommodation in the member of the other species.
- Metabiosis or thanatocresia The commensal takes advantage of the excrement, remains or corpses of another species to protect itself, reproduce or help itself in some way.
Commensalism and mutualism
Unlike commensalism, in which only one species involved benefits, In the case of mutualism, both species benefit from their interaction. This type of case is typical among species that present biological characteristics compatible with each other, and can provide positive feedback, that is, provide mutual benefit.
This is the case, to cite an example, of mycorrhizae: fungi that live among the roots of certain trees, exchanging nutrients and organic matter with them (used by the fungus) in exchange for water (used by the roots of the tree). Both organizations benefit.
Continue in: Mutualism
Examples of commensalism
Some common examples of commensalism are:
- The remoras Small saltwater fish capable of attaching themselves to larger and stronger animals, such as sharks, to take advantage of their ability to swim quickly and move from one place to another quickly.
- Sea acorns A genus of immobile marine crustaceans, they live on the shells of mussels, oysters and other bivalves, as tenants.
- Hermit crabs With a soft abdomen, they take advantage of the empty shells of sea snails to enter and protect themselves, as if it were their own.
- Certain plant species are epiphytic, not parasitic They live on the branches of large trees, thus accessing levels of sunlight that are scarcer at ground level.
Commensalism in the desert
The desert habitat is one of the most extreme in the world and its flora and fauna are adapted to its difficult climatic conditions. This does not prevent them from forming commensalistic relationships, although they certainly occur less frequently than in other friendlier environments. Examples of this are the following:
- The burrows dug underground by rodents are often abandoned, and then other species can live in them and flee from the sun, as do certain types of snakes and scorpions.
- Desert owls take refuge in holes made by other species inside cacti, keeping their young there and gaining protection from the sun and other species.
- Birds of prey are common in the desert, like certain species of vulture, and they feed on any organic remains resulting from hunting larger species.
Other types of interspecific relationships
In addition to commensalism and mutualism, which we have already talked about, there are the following types of interspecific relationships:
- Parasitism It occurs when one species benefits from the other nutritionally or in another way, that is, obtains benefits from it, but in this case causing damage of some kind. A perfect example of this are mosquitoes, which feed on the blood of animals to incubate their eggs, and in return can transmit diseases to them for which they serve as an agent of contagion.
- Symbiosis This is a very narrow degree of mutualism, in which the species involved end up becoming codependent, that is, needing the presence of the other to survive or to be able to complete their life cycles. A good example of this is the relationship between an algae and a fungus to form a lichen, exchanging structure for moisture and nutrients.
- Competence Quite the opposite of commensalism, it occurs when two species compete or confront each other for access to the resources necessary to survive, so only one of them will be able to obtain benefit. This is the case, for example, of the competition between hyenas and vultures, or other African scavengers, to devour the remains of the lion hunt.
- Predation The fundamental type of interaction in the food chain consists of one species (the predator) hunting and devouring another (the prey), thus obtaining a nutritional benefit and ending the existence of the other. This is what happens when a fox hunts a rabbit and devours it.
- Amensalism In this case, the interaction between the species is harmful to one of them, without the other obtaining any type of benefit in return. This is the case with trees such as Eucalyptus or Walnut, for example, which prevent the growth of other plant species around them, without benefiting directly in the process.
References
- “Commensalism” on Wikipedia.
- “Symbiosis in the animal kingdom. Mutualism, commensalism and parasitism” in Zoo Portraits.
- “Commensalism” in La Guía 2000.
- “Commensalism” in Research and Science Magazine.
- “What is commensalism?” (video) at Mona Chocolate.
- “Commensalism” in The Encyclopaedia Britannica.
