Editing Mutualism (biology) (section)

===Service-service relationships===
[[Image:Common clownfish curves dnsmpl.jpg|thumb|[[Ocellaris clownfish]] and [[Heteractis magnifica|Ritter's sea anemone]]s live in a mutual service-service symbiosis, the fish driving off [[butterflyfish]] and the anemone's tentacles protecting the fish from predators.]]

Strict service-service interactions are very rare, for reasons that are far from clear.<ref name="Ollerton06" /> One example is the relationship between [[sea anemone]]s and [[anemone fish]] in the family [[Pomacentridae]]: the anemones provide the fish with protection from [[predator]]s (which cannot tolerate the stings of the anemone's tentacles) and the fish defend the anemones against [[butterflyfish]] (family [[Chaetodontidae]]), which eat anemones. However, in common with many mutualisms, there is more than one aspect to it: in the anemonefish-anemone mutualism, waste [[ammonia]] from the fish feeds the [[symbiotic]] [[algae]] that are found in the anemone's tentacles.<ref>{{cite journal | last1=Porat | first1=D. | last2=Chadwick-Furman | first2=N. E. | year=2004 | title=Effects of anemonefish on giant sea anemones: expansion behavior, growth, and survival | journal=[[Hydrobiologia]] | volume=530 | issue=1–3| pages=513–520 | doi=10.1007/s10750-004-2688-y | bibcode=2004HyBio.530..513P | s2cid=2251533 }}</ref><ref>{{cite journal | last1=Porat | first1=D. | last2=Chadwick-Furman | first2=N. E. | year=2005 | title=Effects of anemonefish on giant sea anemones: ammonium uptake, zooxanthella content and tissue regeneration | journal=Mar. Freshw. Behav. Phys. | volume=38 | issue=1 | pages=43–51 | doi= 10.1080/10236240500057929| bibcode=2005MFBP...38...43P | s2cid=53051081 }}</ref> Therefore, what appears to be a service-service mutualism in fact has a service-resource component. A second example is that of the relationship between some [[ants]] in the genus ''[[Pseudomyrmex]]'' and trees in the [[genus]] ''[[Acacia]]'', such as the [[whistling thorn]] and [[bullhorn acacia]]. The [[ants]] nest inside the plant's thorns. In exchange for shelter, the ants protect acacias from attack by [[herbivores]] (which they frequently eat when those are small enough, introducing a resource component to this service-service relationship) and competition from other plants by trimming back vegetation that would shade the acacia. In addition, another service-resource component is present, as the ants regularly feed on [[lipid]]-rich food-bodies called [[Beltian bodies]] that are on the ''Acacia'' plant.<ref>{{Cite web|url=https://www2.palomar.edu/users/warmstrong/acacia.htm|title=Swollen Thorn Acacias|website=www2.palomar.edu|access-date=2019-02-22|archive-date=27 June 2018|archive-url=https://web.archive.org/web/20180627005136/http://www2.palomar.edu/users/warmstrong/acacia.htm|url-status=dead}}</ref>

In the [[neotropics]], the ant ''[[Myrmelachista schumanni]]'' makes its nest in special cavities in ''[[Duroia hirsuta]]''. Plants in the vicinity that belong to other species are killed with [[formic acid]]. This selective gardening can be so aggressive that small areas of the rainforest are dominated by ''Duroia hirsute''. These peculiar patches are known by local people as "[[devil's garden]]s".<ref name="Piper07">[[Ross Piper|Piper, Ross]] (2007), ''Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals'', [[Greenwood Press (publisher)|Greenwood Press]].</ref>

In some of these relationships, the cost of the ant's protection can be quite expensive. ''[[Cordia]]'' sp. trees in the [[Amazon rainforest]] have a kind of partnership with ''[[Allomerus]]'' sp. ants, which make their nests in modified leaves. To increase the amount of living space available, the ants will destroy the tree's flower buds. The flowers die and leaves develop instead, providing the ants with more dwellings. Another type of ''Allomerus'' sp. ant lives with the ''[[Hirtella]]'' sp. tree in the same forests, but in this relationship, the tree has turned the tables on the ants. When the tree is ready to produce flowers, the ant abodes on certain branches begin to wither and shrink, forcing the occupants to flee, leaving the tree's flowers to develop free from ant attack.<ref name="Piper07" />

The term "species group" can be used to describe the manner in which individual organisms group together. In this non-taxonomic context one can refer to "same-species groups" and "mixed-species groups." While same-species groups are the norm, examples of mixed-species groups abound. For example, zebra (''[[Equus burchelli]]'') and wildebeest (''[[Connochaetes taurinus]]'') can remain in association during periods of long distance [[wikt:migration|migration]] across the [[Serengeti]] as a strategy for thwarting predators. ''[[Cercopithecus mitis]]'' and ''[[Cercopithecus ascanius]]'', species of monkey in the [[Kakamega Forest]] of [[Kenya]], can stay in close proximity and travel along exactly the same routes through the forest for periods of up to 12 hours. These mixed-species groups cannot be explained by the coincidence of sharing the same habitat. Rather, they are created by the active behavioural choice of at least one of the species in question.<ref>{{cite journal |vauthors=Tosh CR, Jackson AL, Ruxton GD |title=Individuals from different-looking animal species may group together to confuse shared predators: simulations with artificial neural networks |journal=Proc. Biol. Sci. |volume=274 |issue=1611 |pages=827–32 |date=March 2007 |pmid=17251090 |pmc=2093981 |doi=10.1098/rspb.2006.3760 }}</ref>