International Encyclopedia of Systems and Cybernetics

A kind of complex symbiosis in ecosystems with numerous heterogeneous components.

Pollination by insects tends to maintain vegetal species which are necessary for the survival of the insects themselves as species. The same effect connects animals which bury seeds of the plants they eat, for example squirrels making stores of acorns.

There is also a kind of negative mutualism. Some trees defend themselves against insect pests with biochemical emissions… and some pests even circonvent these defenses by enzymatically detoxifying these poisons… while the plant's emission acts as a call for the parasite's parasites! (P. GREIG SMITH, 1986; J.F. DOBREMEZ et al, 1995, 912-16).

Such natural controls are more than once destroyed by ill-advised human interventions, as for example the inadequately timed use of pesticides which kills not only the parasite, but altogether the parasites that could maintain them in check.

Mutualism is also a relationship between two organisms, which is beneficial for both.

For example, some trees obtain nutrients from fungi living on their roots. The fungi in turn obtain carbohydrates produced by the leaves of the tree

(It seems that some authors consider this collaboration as symbiosis)

Finally, mutualism may also exist among groups, as for example as reciprocal protection in fish shoals, or in herbivorous herds (zebras, antilopes) in which all members benefit from the collectively fostered vigilance against predators.

→ Commensalism; Cooperation; Herd effects; Parasitism; Stigmergy; Symbiosis