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'A ''Mutualism' is an interaction between individuals of two different species, where both individuals derive a fitness benefit, for example increased survivorship. Similar interactions within a species are known as co-operation. Mutualism may be classified in terms of the closeness of association, the closest being symbiosis, which is often confused with mutualism. One or both species involved in the interaction may be , meaning they cannot survive in the short or long term without the other species. Though mutualism has historically received less attention than other interactions such as predation,^[1] it is very important subject in ecology. Examples include cleaner fish, pollination and seed dispersal, gut flora and nitrogen fixation by fungi.

Contents

Classification

Examples

See also

References

Specific

General

Further reading

Classification

★ Lifelong interactions involving close physical and biochemical contact (known as symbiosis), such as those between plants and mycorrhizal fungi

★ Briefer, non-symbiotic interactions, such as those between flowering plants and pollinators.

★ Obligatory or non-obligatory (facultative). For example, bacteria known as rhizobia reproduce either in the soil or in (usually) mutualistic symbiosis with legume plants (Denison & Kiers 2004). Mycorrhizal fungi, on the other hand, can be totally dependent on their plant hosts. microbes often band together for mutual benefit in biofilms to break down solid food sources as in rusticles. The relationship between people and their pets is a non-obligatory mutualism for the human, and, depending on the animal, either obligatory or non-obligatory.
The question how and why species might cooperate has also been addressed philosophically. Gilles Deleuze, for example, is interested in the way this questioned the conception of evolutionism and the notion of linear historical progress.

Examples

Some examples of mutualism are the relationships between bees and flowers, or the example of ants and a shrub brush called Bullhorn Acacia.
In the acacia example, certain ants (e.g. ''Pseudomyrmex spinicola'') nest inside the plant's thorns. In exchange for food and shelter, ants protect acacias from attack by herbivores and competition from other plants. The ants reduce competition by trimming back vegetation that shades the shrub.
Some species of ants also "farm" aphids, protecting them on the plant they eat, and eating the honeydew that the aphids secrete.
A famous land version of symbiosis is the relationship of the Egyptian Plover bird and the crocodile. In this relationship, the bird is well known for preying on parasites that feed on crocodiles. To that end, the crocodile openly invites the bird to hunt on its body, even going so far as to open its jaws to allow the bird enter the mouth safely to hunt the leeches from its gums. For the bird, this relationship not only is a ready source of food, but a safe one considering that few predator species would dare strike at the bird at such proximity to its host.
Many plants will function in a voluntary mutualistic relationship as companion plants, providing each other with shelter, fertilization, the repelling of pests, et cetera. For example, beans may grow up cornstalks as a trellis, while fixing nitrogen in the soil for the corn, as exploited in the three sisters gardening technique.

See also

★ Ecological facilitation

★ Co-adaptation

★ Co-evolution

References

Specific

1. Begon, M., J.L. Harper and C.R. Townsend. 1996. ''Ecology: individuals, populations, and communities'', Third Edition. Blackwell Science Ltd., Cambridge, Massachusetts, USA.

General

★ Breton, Lorraine M., and John F. Addicott. 1992. Density-Dependent Mutualism in an Aphid-Ant Interaction. Ecology, Vol. 73, No. 6, pp. 2175-2180.

★ Bronstein, JL. 1994. Our current understand of mutualism. Quarterly Review of Biology 69 (1): 31-51 MAR 1994

★ Bronstein JL, 2001. The exploitation of mutualisms. Ecology Letters 4 (3): 277-287

★ Bronstein JL, 2001. The costs of mutualism. American Zoologist 41 (4): 825-839 S

★ Bronstein JL, Alarcon R, Geber M. 2006. The evolution of plant-insect mutualisms. New Phytologist 172 (3): 412-428

★ Denison RF, Kiers ET 2004. Why are most rhizobia beneficial to their plant hosts, rather than parasitic? Microbes and Infection 6 (13): 1235-1239

★ DeVries, PJ; and Baker, I. 1989. Butterfly exploitation of an ant-plant mutualism: Adding insult of herbivory. Journal of the New York Entomological Society [J. N.Y. ENTOMOL. SOC.]. Vol. 97, no. 3, pp. 332-340.

★ Hoeksema, J.D. & E.M.Bruna. 2000. Pursuing the big questions about interspecific mutualism: a review of theoretical approaches. Oecologia 125:321-330

★ Jahn, G.C. and J.W. Beardsley 2000. Interactions of ants (Hymenoptera: Formicidae) and mealybugs (Homoptera: Pseudococcidae) on pineapple. Proceedings of the Hawaiian Entomological Society 34: 181-185.

★ Jahn, Gary C., J. W. Beardsley and H. González-Hernández 2003. A review of the association of ants with mealybug wilt disease of pineapple. Proceedings of the Hawaiian Entomological Society. 36:9-28.

★ Noe, R. & P. Hammerstein. 1994. Biological markets: supply and demand determine the effect of partner choice in cooperation, mutualism and mating. Behavioral Ecology and Sociobiology 35:1-11

★ Paszkowski, U. 2006. Mutualism and parasitism: the yin and yang of plant symbioses. Current Opinion on Plant Biology 9 (4): 364-370.

Further reading

★ Boucher, D.G., James, S. & Kresler, K. (1984) The ecology of mutualism. ''Annual Review of Ecology and Systemattics'', '13': 315-347.