kommensalisme

Kommensalisme is a type of symbiotic relationship between two different biological species where one organism benefits and the other is neither harmed nor helped. This interaction is distinct from mutualism, where both species benefit, and parasitism, where one species benefits at the expense of the other. In commensalism, the organism that benefits is known as the commensal, while the other organism is called the host.

The benefits for the commensal can take various forms. Some commensals may gain shelter or a place to live on the host. For example, barnacles often attach themselves to whales, gaining a stable surface to filter feed from while the whale is largely unaffected. Others may benefit from food scraps left by the host. Remoras, small fish with a suction disc on their heads, attach to larger marine animals like sharks and feed on the leftovers from the shark's meals.

In some cases, the commensal might utilize the host for transportation, a phenomenon called phoresy. An example of this is when certain mites attach themselves to insects to be carried to new locations where they can find food or suitable breeding grounds. Another form of commensalism involves one organism using the other's waste products. For instance, some species of fungi grow on decaying organic matter, obtaining nutrients without directly impacting the source organism's health before its demise.

Identifying true commensalism can sometimes be challenging, as subtle negative impacts on the host might be difficult to detect or may only occur under specific environmental conditions. However, it remains a recognized and important ecological interaction that shapes the dynamics of many ecosystems.