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Within a biocenosis, different types of relationships are established between organisms or living beings. These relationships are called biotic relationships and can be intraspecific, when they are established between organisms of the same species, and interspecific, when they are established between organisms of different species, regardless of whether they are plants, animals or microorganisms of other types.

With this article by Green Ecologist, we want to help you learn in a simple way everything about the interspecific relationships: types and examples.

Types of interspecific relationships

There are different types of interspecific relationships that can occur between the organisms of a community and are defined in relation to the beneficial (+), harmful (-) or neutral (0) effect for each of the individuals involved.

  • Relationships (0) / (+)
  • Ratio (+) / (0)
  • Relationships (+) / (-)
  • Ratio (+) / (+)
  • Ratio (-) / (-) or (+)

We explain each of these below types of interspecific relationships with examples.

Interspecific relationships of the type (0) / (+)

Within the types of relationships between species called (0) / (+) we find these types:

  • Amensalism: relationship in which one individual produces a toxic substance for another, such as eucalyptus (Eucalyptus globulus) secretes substances that damage and prevent the growth of plant species around it.
  • Antibiosis: It occurs when a species secretes harmful substances for another species that competes with it. A classic example of antibiosis is the fungus Penicillium, which produces substances that inhibit the growth of microorganisms around it. Learn more about this type of interspecific relationship with this other Green Ecologist article on Antibiosis: definition and examples.

Relationships between species of the type (+) / (0)

The interspecific relationships known as the (+) / (0) type are as follows:

  • Epibiosis: is established when a sessile and harmless organism (epibiont), lives on top of another living being (basibiont). An example of this type of relationship is between epibionts such as barnacles, remoras or algae and basibionts such as whales, sharks or sea turtles.
  • Thanatocresis: relationship that occurs when an individual uses the remains of other dead organisms for their own benefit such as excrement or secretions. An example is the hermit crab (Eupagurus bernhardus), which takes refuge and protects using the empty shell of a snail.
  • Foresia: relationship that is established when one species uses another as a means of transport and movement, without causing harm. An example of phoresis occurs when a mite uses the abdomen of certain types of beetles to move without wasting energy.
  • Commensalism: one of the participating species (the diner) benefits from another (the host), without causing benefit or harm. Actually, within the term commensalism, one can encompass phoresia, epibiosis, thanatocresis and inquilinism.
  • Tenancy: It occurs when one of the species lives in the refuge or burrow of another. An example of this relationship is between epiphytic plants and some types of trees or insects that inhabit the burrows of country mice.

Interspecific relationships (+) / (-)

Within the type (+) / (-) of relationships between species we find:

  • Predation: relationship that implies the capture and death of some organisms (predators) over others (prey). Predation is a relationship between two free-living species, with no previous or direct relationship between them. It is one of the most important relationships from the point of view of natural selection and the same organism can be a predator and in turn prey to others. Examples are numerous, such as the polar bear that preys on seals and reindeer or the anteater with termites and ants.
  • Parasitism: an individual (parasite) lives at the expense of the fluids of another individual (host), which is harmed, but does not cause death in the short term. They can be ectoparasites when they live outside the host, feeding on its blood or sap. An example of an ectoparasite is the tick. On the contrary, endoparasites live in the internal environment of the host, evolving with it. An example of endoparasites is intestinal worms or whipworms. For example, in this other article we explain the Parasites that affect plants.
  • Exploitation: relationship in which a group of individuals benefit from others, who are harmed. Within this category, predation or parasitism can be included.

Relations between species of the type (+) / (+)

In this type of relationship between species, the so-called (+) / (+) we can find these two types and subtypes:


In this type of relationship, both organisms (symbionts) benefit from some process of the other with which they have a close relationship. A classic and very frequent example is that of lichens, where a fungus (or mycobiont) benefits from the photosynthesis of an alga (phycobiont), which benefits from the protection of the fungus against factors such as desiccation.

You can learn more about symbiosis with this other article about What is symbiosis with examples and by watching the video below.


It is a type of relationship very similar to symbiosis, with the difference that the relationship between the two organisms is not so intimate. We can differentiate it in turn in:

  • Resource-resource relationship: one type of resource is exchanged for another. For example, nitrogen-fixing rhizobia and legumes exchange nitrogen for carbohydrates or carbohydrates.
  • Service-natural resource relationship: an example is pollination, in which nectar (natural resource) is exchanged for pollen dispersal (service). This is one of the reasons for the great importance of bees and other pollinating living beings.
  • Service-service relationship: An example is the relationship established between the sea anemone and the clownfish, which exchange protection (services).

Interspecific relationship of type (-) / (-) or (+)

The relationship between species of the type (-) / (-) or (+) is called competition. It is a relationship that is established between two species competing for a resource, either abiotic or biotic, such as water, territory, couple or food. It is one of the most important relationships from the point of view of natural selection, since it can determine that a species reduces its reproductive rate or, in extreme cases, becomes extinct because it cannot adapt to competition. Can be:

  • Competition for exploitation: a species consumes and uses a resource more efficiently, reducing its availability to others. An example is competition between aphids that consume tree sap. In this case, the aphid species that consumes the most resources, leaves less for the other.
  • Competition by interference: a species interferes directly in the way of obtaining food and in the fact of obtaining it, in the survival or in the reproduction of another species through acts such as aggression. An example is the territorial competition that occurs in ants.

If you want to read more articles similar to Interspecific relationships: types and examples, we recommend that you enter our Biology category.

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