Interspecific competition

Interspecific competition is the competition for resources ( competition ) between individuals of different species . Interspecific competition is one of the most important influencing factors of population dynamics . It acts as a selection factor and thus causes evolution .

Competition is a form of antagonistic relationships between different individuals. It is based on the utilization (also: exploitation) of resources . This means that even individuals who never meet directly can compete with one another, e.g. B. when they use the same food. Competition between species is usually asymmetrical; H. the effects on one (competitive) species are much stronger than those on the other (competitive). There is then a tendency for the inferior species (or in the case of symmetrical competition: both species) to evade the competition, e.g. B. it can acquire adaptations through which it can take advantage of a different food spectrum than the competitor. This process is known as niching, it means that the ecological niches of the competing species overlap less strongly. If there is competition for an essential and non-substitutable resource, the superior competitor can force the inferior out of the common living space, this is called the exclusion of competition .

Competition between individuals of the same species is called intraspecific competition .

For the scientific description of interspecific competition, biologists mostly use systems of ordinary differential equations.

For example, a competitive relationship of two types can be described in the form:

{\ displaystyle {\ frac {dx} {dt}} = ax \ left (1 - {\ frac {x} {K1-cY}} \ right)}

{\ displaystyle {\ frac {dy} {dt}} = by \ left (1 - {\ frac {y} {K2-dX}} ​​\ right)}

The variables and the growth constants are occupied as usual and represent interaction terms. ${\ displaystyle X, Y}$ ${\ displaystyle a, b}$ ${\ displaystyle c, d}$

An important form of interspecific competition is food competition : different species prefer the same food or prey .

Individual evidence

^ J. Murray: Mathematical Biology . Springer, 1989

[1] J. Murray: Mathematical Biology . Springer, 1989