Coevolution

{{main|Mutualism (biology)}}

Coevolution is the evolution of two or more species which reciprocally affect each other, sometimes creating a mutualistic relationship between the species. Such relationships can be of many different types.{{cite book |title=Coevolution |editor1-link=Douglas J. Futuyma|editor1-last=Futuyma|editor1-first = D. J.|editor2-first= M.|editor2-last= Slatkin |year=1983 |publisher=Sinauer Associates |isbn=978-0-87893-228-3 }}

Flowers appeared and diversified relatively suddenly in the fossil record, creating what Charles Darwin described as the "abominable mystery" of how they had evolved so quickly; he considered whether coevolution could be the explanation.{{cite journal |last=Friedman |first=W. E. |date=January 2009 |title=The meaning of Darwin's 'abominable mystery' |journal=American Journal of Botany |volume=96 |issue=1 |pages=5–21 |doi=10.3732/ajb.0800150 |pmid=21628174 }} He first mentioned coevolution as a possibility in On the Origin of Species, and developed the concept further in Fertilisation of Orchids (1862).{{cite book |first=John N. |last=Thompson |title=The coevolutionary process |publisher=University of Chicago Press |location=Chicago |year=1994 |isbn=978-0-226-79760-1 |url=https://books.google.com/books?id=AyXPQzEwqPIC&q=Wallace+%22creation+by+law%22+Angr%C3%A6cum&pg=PA27 |access-date=2009-07-27}}{{cite book |last=Darwin |first=Charles |year=1859 |title=On the Origin of Species |edition=1st |location=London |publisher=John Murray |url=http://darwin-online.org.uk/content/frameset?itemID=F373&viewtype=text&pageseq=1 |access-date=2009-02-07}}{{cite book |last=Darwin |first=Charles |year=1877 |title=On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing |location=London |publisher=John Murray |edition=2nd |url=http://darwin-online.org.uk/content/frameset?itemID=F801&viewtype=text&pageseq=1 |access-date=2009-07-27}}

{{Further|Entomophily}}

File:Apis mellifera - Melilotus albus - Keila.jpg taking a reward of nectar and collecting pollen in its pollen baskets from white melilot flowers]]

Modern insect-pollinated (entomophilous) flowers are conspicuously coadapted with insects to ensure pollination and in return to reward the pollinators with nectar and pollen. The two groups have coevolved for over 100 million years, creating a complex network of interactions. Either they evolved together, or at some later stages they came together, likely with pre-adaptations, and became mutually adapted.{{cite journal |last=Lunau |first=Klaus |title=Adaptive radiation and coevolution — pollination biology case studies |journal=Organisms Diversity & Evolution |date=2004 |volume=4 |issue=3 |pages=207–224 |doi=10.1016/j.ode.2004.02.002 |doi-access= |bibcode=2004ODivE...4..207L }}{{cite book |last=Pollan |first=Michael |author-link=Michael Pollan |title=The Botany of Desire: A Plant's-eye View of the World |publisher=Bloomsbury |isbn=978-0-7475-6300-6 |title-link=The Botany of Desire |year=2003}}

Several highly successful insect groups—especially the Hymenoptera (wasps, bees and ants) and Lepidoptera (butterflies and moths) as well as many types of Diptera (flies) and Coleoptera (beetles)—evolved in conjunction with flowering plants during the Cretaceous (145 to 66 million years ago). The earliest bees, important pollinators today, appeared in the early Cretaceous.{{cite web |title=Coevolution of angiosperms and insects |url=http://palaeo.gly.bris.ac.uk/Palaeofiles/Angiosperms/coevolution.htm |publisher=University of Bristol Palaeobiology Research Group |access-date=16 January 2017 |archive-url=https://web.archive.org/web/20161220033247/http://palaeo.gly.bris.ac.uk/Palaeofiles/Angiosperms/coevolution.htm |archive-date=20 December 2016 |url-status=dead }} A group of wasps sister to the bees evolved at the same time as flowering plants, as did the Lepidoptera. Further, all the major clades of bees first appeared between the middle and late Cretaceous, simultaneously with the adaptive radiation of the eudicots (three quarters of all angiosperms), and at the time when the angiosperms became the world's dominant plants on land.{{cite journal |last1=Cardinal |first1=Sophie |last2=Danforth |first2=Bryan N. |title=Bees diversified in the age of eudicots |journal=Proceedings of the Royal Society B |date=2013 |doi=10.1098/rspb.2012.2686 |volume=280 |issue=1755 |pages=20122686 |pmid=23363629 |pmc=3574388}}

At least three aspects of flowers appear to have coevolved between flowering plants and insects, because they involve communication between these organisms. Firstly, flowers communicate with their pollinators by scent; insects use this scent to determine how far away a flower is, to approach it, and to identify where to land and finally to feed. Secondly, flowers attract insects with patterns of stripes leading to the rewards of nectar and pollen, and colours such as blue and ultraviolet, to which their eyes are sensitive; in contrast, bird-pollinated flowers tend to be red or orange. Thirdly, flowers such as some orchids mimic females of particular insects, deceiving males into pseudocopulation.{{cite book |first1=Leendert |last1=van der Pijl |first2=Calaway H. |last2=Dodson |title=Orchid Flowers: Their Pollination and Evolution |chapter-url=https://archive.org/details/orchidflowersthe0000pijl |chapter-url-access=registration |chapter=Chapter 11: Mimicry and Deception |publisher=University of Miami Press |location=Coral Gables |year=1966 |pages=[https://archive.org/details/orchidflowersthe0000pijl/page/129 129–141] |isbn=978-0-87024-069-0}}

The yucca, Yucca whipplei, is pollinated exclusively by Tegeticula maculata, a yucca moth that depends on the yucca for survival.{{cite web|title=Pollination Partnerships Fact Sheet |work=Flora of North America |year=2004 |first=Claire |last= Hemingway |page= 2|url=http://fna.huh.harvard.edu/files/imported/Outreach/FNAfs_yucca.pdf |quote=Yucca and Yucca Moth|archive-url = https://web.archive.org/web/20110817052152/http://fna.huh.harvard.edu/files/imported/Outreach/FNAfs_yucca.pdf |archive-date = 17 August 2011}} The moth eats the seeds of the plant, while gathering pollen. The pollen has evolved to become very sticky, and remains on the mouth parts when the moth moves to the next flower. The yucca provides a place for the moth to lay its eggs, deep within the flower away from potential predators.{{cite journal |last1=Pellmyr |first1=Olle |last2=Leebens-Mack |first2=James |title=Forty million years of mutualism: Evidence for Eocene origin of the yucca-yucca moth association |journal=PNAS |date=August 1999 |pmid=10430916 |volume=96 |issue=16 |pmc=17753 |pages=9178–9183 |bibcode=1999PNAS...96.9178P |doi=10.1073/pnas.96.16.9178 |doi-access=free }}

{{Further|Ornithophily}}

File:Purple-throated carib hummingbird feeding.jpg feeding from and pollinating a flower]]

Hummingbirds and ornithophilous (bird-pollinated) flowers have evolved a mutualistic relationship. The flowers have nectar suited to the birds' diet, their color suits the birds' vision and their shape fits that of the birds' bills. The blooming times of the flowers have also been found to coincide with hummingbirds' breeding seasons. The floral characteristics of ornithophilous plants vary greatly among each other compared to closely related insect-pollinated species. These flowers also tend to be more ornate, complex, and showy than their insect pollinated counterparts. It is generally agreed that plants formed coevolutionary relationships with insects first, and ornithophilous species diverged at a later time. There is not much scientific support for instances of the reverse of this divergence: from ornithophily to insect pollination. The diversity in floral phenotype in ornithophilous species, and the relative consistency observed in bee-pollinated species can be attributed to the direction of the shift in pollinator preference.{{cite journal |last1=Kay |first1=Kathleen M.|last2=Reeves |first2=Patrick A. |last3=Olmstead |first3=Richard G. |last4=Schemske|first4=Douglas W. |s2cid=2991957|title=Rapid speciation and the evolution of hummingbird pollination in neotropical Costus subgenus Costus (Costaceae): evidence from nrDNA ITS and ETS sequences |journal=American Journal of Botany |date=2005 |volume=92 |issue=11|pages=1899–1910 |doi=10.3732/ajb.92.11.1899 |pmid=21646107|doi-access= }}

Flowers have converged to take advantage of similar birds.{{cite journal |last1=Brown |first1=James H. |last2=Kodric-Brown |first2=Astrid |title=Convergence, Competition, and Mimicry in a Temperate Community of Hummingbird-Pollinated Flowers |s2cid=53604204 |journal=Ecology |year=1979 |volume=60 |issue=5 |pages=1022–1035 |doi=10.2307/1936870|jstor=1936870|bibcode=1979Ecol...60.1022B }} Flowers compete for pollinators, and adaptations reduce unfavourable effects of this competition. The fact that birds can fly during inclement weather makes them more efficient pollinators where bees and other insects would be inactive. Ornithophily may have arisen for this reason in isolated environments with poor insect colonization or areas with plants which flower in the winter.{{cite journal |last1=Cronk |first1=Quentin |last2=Ojeda |first2=Isidro |title=Bird-pollinated flowers in an evolutionary and molecular context |journal=Journal of Experimental Botany |date=2008 |volume=59 |issue=4 |pages=715–727 |doi=10.1093/jxb/ern009|pmid=18326865|doi-access=free }} Bird-pollinated flowers usually have higher volumes of nectar and higher sugar production than those pollinated by insects.{{cite journal |last=Stiles |first=F. Gary |title=Geographical Aspects of Bird Flower Coevolution, with Particular Reference to Central America |journal=Annals of the Missouri Botanical Garden |year=1981 |volume=68 |issue=2 |pages=323–351 |doi=10.2307/2398801 |jstor=2398801 |bibcode=1981AnMBG..68..323S |s2cid=87692272 |url=https://www.biodiversitylibrary.org/part/38387 }} This meets the birds' high energy requirements, the most important determinants of flower choice. In Mimulus, an increase in red pigment in petals and flower nectar volume noticeably reduces the proportion of pollination by bees as opposed to hummingbirds; while greater flower surface area increases bee pollination. Therefore, red pigments in the flowers of Mimulus cardinalis may function primarily to discourage bee visitation.{{cite journal |last1=Schemske |first1=Douglas W. |last2=Bradshaw |first2=H.D. |title=Pollinator preference and the evolution of floral traits in monkeyflowers (Mimulus) |journal=Proceedings of the National Academy of Sciences |date=1999 |volume=96 |issue=21 |pages=11910–11915 |doi=10.1073/pnas.96.21.11910|pmid=10518550 |bibcode=1999PNAS...9611910S |pmc=18386|doi-access=free }} In Penstemon, flower traits that discourage bee pollination may be more influential on the flowers' evolutionary change than 'pro-bird' adaptations, but adaptation 'towards' birds and 'away' from bees can happen simultaneously.{{cite journal |last1=Castellanos|first1=M. C. |last2=Wilson |first2=P. |last3=Thomson |first3=J.D. |title='Anti-bee' and 'pro-bird' changes during the evolution of hummingbird pollination in Penstemon flowers |journal=Journal of Evolutionary Biology |date=2005 |volume=17 |issue=4 |pages=876–885 |doi=10.1111/j.1420-9101.2004.00729.x |pmid=15271088|doi-access=free }} However, some flowers such as Heliconia angusta appear not to be as specifically ornithophilous as had been supposed: the species is occasionally (151 visits in 120 hours of observation) visited by Trigona stingless bees. These bees are largely pollen robbers in this case, but may also serve as pollinators.{{cite journal |last1=Stein |first1=Katharina |last2=Hensen |first2=Isabell |title=Potential Pollinators and Robbers: A Study of the Floral Visitors of Heliconia Angusta (Heliconiaceae) And Their Behaviour |journal=Journal of Pollination Ecology |date=2011 |volume=4 |issue=6 |pages=39–47|doi=10.26786/1920-7603(2011)7|doi-access=free }}

Following their respective breeding seasons, several species of hummingbirds occur at the same locations in North America, and several hummingbird flowers bloom simultaneously in these habitats. These flowers have converged to a common morphology and color because these are effective at attracting the birds. Different lengths and curvatures of the corolla tubes can affect the efficiency of extraction in hummingbird species in relation to differences in bill morphology. Tubular flowers force a bird to orient its bill in a particular way when probing the flower, especially when the bill and corolla are both curved. This allows the plant to place pollen on a certain part of the bird's body, permitting a variety of morphological co-adaptations.

Ornithophilous flowers need to be conspicuous to birds. Birds have their greatest spectral sensitivity and finest hue discrimination at the red end of the visual spectrum, so red is particularly conspicuous to them. Hummingbirds may also be able to see ultraviolet "colors". The prevalence of ultraviolet patterns and nectar guides in nectar-poor entomophilous (insect-pollinated) flowers warns the bird to avoid these flowers. Each of the two subfamilies of hummingbirds, the Phaethornithinae (hermits) and the Trochilinae, has evolved in conjunction with a particular set of flowers. Most Phaethornithinae species are associated with large monocotyledonous herbs, while the Trochilinae prefer dicotyledonous plant species.

File:Ficus plant.jpg exposing its many tiny matured, seed-bearing gynoecia. These are pollinated by the fig wasp, Blastophaga psenes. In the cultivated fig, there are also asexual varieties.]]

{{Main|Reproductive coevolution in Ficus}}

The genus Ficus is composed of 800 species of vines, shrubs, and trees, including the cultivated fig, defined by their syconia, the fruit-like vessels that either hold female flowers or pollen on the inside. Each fig species has its own fig wasp which (in most cases) pollinates the fig, so a tight mutual dependence has evolved and persisted throughout the genus.{{cite journal |last1=Suleman |first1=Nazia |last2=Sait |first2=Steve |last3=Compton |first3=Stephen G. |title=Female figs as traps: Their impact on the dynamics of an experimental fig tree-pollinator-parasitoid community |journal=Acta Oecologica |volume=62 |year=2015 |pages=1–9 |doi=10.1016/j.actao.2014.11.001 |bibcode=2015AcO....62....1S|url=http://eprints.whiterose.ac.uk/85568/7/Female%20plants%20as%20traps%20paper%20%283%29.pdf }}

File:Ant - Pseudomyrmex species, on Bull Thorn Acacia (Acacia cornigera) with Beltian bodies, Caves Branch Jungle Lodge, Belmopan, Belize - 8505045055.jpg) with Beltian bodies that provide the ants with protein]]

{{Main|Pseudomyrmex ferruginea}}

The acacia ant (Pseudomyrmex ferruginea) is an obligate plant ant that protects at least five species of "Acacia" (Vachellia){{efn|The acacia ant protects at least 5 species of "Acacia", now all renamed to Vachellia: V. chiapensis, V. collinsii, V. cornigera, V. hindsii, and V. sphaerocephala.}} from preying insects and from other plants competing for sunlight, and the tree provides nourishment and shelter for the ant and its larvae.{{cite book |last1=Hölldobler |first1=Bert |last2=Wilson |first2=Edward O. |title=The ants |publisher=Harvard University Press |year=1990 |url=https://archive.org/details/ants0000hlld |url-access=registration |isbn=978-0-674-04075-5 |pages=[https://archive.org/details/ants0000hlld/page/532 532]–533}}{{cite web |website=National Geographic |title=Acacia Ant Video |url=http://video.nationalgeographic.com/video/player/animals/bugs-animals/ants-and-termites/ant_acaciatree.html|url-status=dead|archive-url=https://web.archive.org/web/20071107085438/http://video.nationalgeographic.com/video/player/animals/bugs-animals/ants-and-termites/ant_acaciatree.html|archive-date=2007-11-07}} Such mutualism is not automatic: other ant species exploit trees without reciprocating, following different evolutionary strategies. These cheater ants impose important host costs via damage to tree reproductive organs, though their net effect on host fitness is not necessarily negative and, thus, becomes difficult to forecast.{{cite journal |last1=Palmer |first1=Todd M. |last2=Doak |first2=Daniel F. |last3=Stanton |first3=Maureen L. |last4=Bronstein |first4=Judith L. |last5=Kiers |first5=E. Toby |last6=Young |first6=Truman P. |last7=Goheen |first7=Jacob R. |last8=Pringle |first8=Robert M. |display-authors=3 |title=Synergy of multiple partners, including freeloaders, increases host fitness in a multispecies mutualism |journal=Proceedings of the National Academy of Sciences |volume=107 |issue=40 |date=2010-09-20 |issn=0027-8424 |doi=10.1073/pnas.1006872107 |pages=17234–17239 |pmid=20855614 |pmc=2951420 |bibcode=2010PNAS..10717234P |doi-access=free }}{{cite journal |title=Kinship and incompatibility between colonies of the acacia ant Pseudomyrex ferruginea |journal=Behavioral Ecology and Sociobiology |first1=Alex |last1=Mintzer |last2=Vinson |first2=S. B. |volume=17 |issue=1 |pages=75–78 |doi=10.1007/bf00299432 |jstor=4599807 |year=1985 |bibcode=1985BEcoS..17...75M |s2cid=9538185 }}

{{Main|Host–parasite coevolution}}

Host–parasite coevolution is the coevolution of a host and a parasite.{{cite journal |doi=10.1038/ng1202-569 |last1=Woolhouse |first1=M. E. J. |last2=Webster |first2=J. P. |last3=Domingo |first3=E. |last4=Charlesworth |first4=B. |last5=Levin |first5=B. R. |title=Biological and biomedical implications of the coevolution of pathogens and their hosts |journal=Nature Genetics |date=December 2002 |pmid=12457190 |volume=32 |issue=4 |pages=569–77 |url=http://www.era.lib.ed.ac.uk/bitstream/1842/689/2/Charlesworth_Woolhouse.pdf |hdl=1842/689 |s2cid=33145462 |hdl-access=free }} A general characteristic of many viruses, as obligate parasites, is that they coevolved alongside their respective hosts. Correlated mutations between the two species enter them into an evolution arms race. Whichever organism, host or parasite, that cannot keep up with the other will be eliminated from their habitat, as the species with the higher average population fitness survives. This race is known as the Red Queen hypothesis.{{cite journal |last=Van Valen |first=L. |date=1973 |title=A New Evolutionary Law |journal=Evolutionary Theory |volume=1 |pages=1–30}} cited in: [http://pespmc1.vub.ac.be/REDQUEEN.html The Red Queen Principle] The Red Queen hypothesis predicts that sexual reproduction allows a host to stay just ahead of its parasite, similar to the Red Queen's race in Through the Looking-Glass: "it takes all the running you can do, to keep in the same place".{{cite book |last=Carroll |first=Lewis |author-link=Lewis Carroll |orig-year=1871 |title=Through the Looking-glass: And what Alice Found There |url=https://books.google.com/books?id=cJJZAAAAYAAJ |publisher=Macmillan |date=1875 |page=42 |quote=it takes all the running you can do, to keep in the same place.}} The host reproduces sexually, producing some offspring with immunity over its parasite, which then evolves in response.{{cite journal |doi=10.1038/srep10004 |last=Rabajante |first=J. |display-authors=etal |title=Red Queen dynamics in multi-host and multi-parasite interaction system |journal=Scientific Reports |year=2015 |volume=5 |pages=10004 |pmid=25899168 |pmc=4405699 |bibcode=2015NatSR...510004R}}

The parasite–host relationship probably drove the prevalence of sexual reproduction over the more efficient asexual reproduction. It seems that when a parasite infects a host, sexual reproduction affords a better chance of developing resistance (through variation in the next generation), giving sexual reproduction variability for fitness not seen in the asexual reproduction, which produces another generation of the organism susceptible to infection by the same parasite.{{cite web |title=Sexual reproduction works thanks to ever-evolving host, parasite relationships |website=PhysOrg |url=https://phys.org/news/2011-07-sexual-reproduction-ever-evolving-host-parasite.html |date=7 July 2011}}{{cite journal |last1=Morran |first1=L.T. |author2=Schmidt, O.G. |author3=Gelarden, I.A. |author4=Parrish, R.C. II |author5= Lively, C.M. |title=Running with the Red Queen: Host-Parasite Coevolution Selects for Biparental Sex |journal=Science |volume=333 |issue=6039 |pages=216–8 |date=8 July 2011 |id=Science.1206360 |bibcode=2011Sci...333..216M |doi=10.1126/science.1206360 |pmid=21737739 |pmc=3402160}}{{cite encyclopedia |author=Hogan, C. Michael |date=2010 |url=https://editors.eol.org/eoearth/wiki/Virus |title=Virus |encyclopedia=Encyclopedia of Earth |editor=Cutler Cleveland |editor2=Sidney Draggan}} Coevolution between host and parasite may accordingly be responsible for much of the genetic diversity seen in normal populations, including blood-plasma polymorphism, protein polymorphism, and histocompatibility systems.{{cite journal |author1=Anderson, R. |author2=May, R. |date=October 1982 |title=Coevolution of hosts and parasites |journal=Parasitology |volume=85 |issue=2 |pages=411–426 |doi=10.1017/S0031182000055360 |pmid=6755367|s2cid=26794986 }}

File:Reed warbler cuckoo.jpg: Eurasian reed warbler raising a common cuckoo]]

{{Main|Brood parasitism}}

Brood parasitism demonstrates close coevolution of host and parasite, for example in some cuckoos. These birds do not make their own nests, but lay their eggs in nests of other species, ejecting or killing the eggs and young of the host and thus having a strong negative impact on the host's reproductive fitness. Their eggs are camouflaged as eggs of their hosts, implying that hosts can distinguish their own eggs from those of intruders and are in an evolutionary arms race with the cuckoo between camouflage and recognition. Cuckoos are counter-adapted to host defences with features such as thickened eggshells, shorter incubation (so their young hatch first), and flat backs adapted to lift eggs out of the nest.{{cite web |last1=Weiblen |first1=George D. |title=Interspecific Coevolution |url=http://geo.cbs.umn.edu/Weiblen2003.pdf |publisher=Macmillan |date=May 2003}}{{cite journal |last1=Rothstein |first1=S.I |year=1990 |title=A model system for coevolution: avian brood parasitism |journal=Annual Review of Ecology and Systematics |volume=21 |pages=481–508 |doi=10.1146/annurev.ecolsys.21.1.481}}{{Cite book |last=Davies |first=Nicholas B. |others=McCallum, James (Wildlife artist) |title=Cuckoo : cheating by nature |date=7 April 2015 |isbn=978-1-62040-952-7 |edition=First U.S. |location=New York, NY |oclc=881092849}}

Antagonistic coevolution is seen in the harvester ant species Pogonomyrmex barbatus and Pogonomyrmex rugosus, in a relationship both parasitic and mutualistic. The queens are unable to produce worker ants by mating with their own species. Only by crossbreeding can they produce workers. The winged females act as parasites for the males of the other species as their sperm will only produce sterile hybrids. But because the colonies are fully dependent on these hybrids to survive, it is also mutualistic. While there is no genetic exchange between the species, they are unable to evolve in a direction where they become too genetically different as this would make crossbreeding impossible.{{cite journal |last1=Herrmann |first1=M. |last2=Cahan |first2=S. H. |title=Inter-genomic sexual conflict drives antagonistic coevolution in harvester ants |journal=Proceedings of the Royal Society B: Biological Sciences |volume=281 |issue=1797 |date=29 October 2014 |doi=10.1098/rspb.2014.1771 |pmid=25355474 |pages=20141771 |pmc=4240986}}

File:Leopard kill - KNP - 001.jpg killing a bushbuck]]

{{Main|Predation}}

Predators and prey interact and coevolve: the predator to catch the prey more effectively, the prey to escape. The coevolution of the two mutually imposes selective pressures. These often lead to an evolutionary arms race between prey and predator, resulting in anti-predator adaptations.{{cite web|title=Predator-Prey Relationships|url=https://necsi.edu/predator-prey-relationships|publisher=New England Complex Systems Institute|access-date=17 January 2017}}

The same applies to herbivores, animals that eat plants, and the plants that they eat. Paul R. Ehrlich and Peter H. Raven in 1964 proposed the theory of escape and radiate coevolution to describe the evolutionary diversification of plants and butterflies.{{cite journal |last1=Ehrlich |first1=Paul R. |author1-link=Paul R. Ehrlich |last2=Raven |first2=Peter H. |author2-link= Peter H. Raven |year=1964 |title=Butterflies and Plants: A Study in Coevolution |journal=Evolution |volume=18 |issue=4 |pages=586–608 |doi=10.2307/2406212 |jstor=2406212}} In the Rocky Mountains, red squirrels and crossbills (seed-eating birds) compete for seeds of the lodgepole pine. The squirrels get at pine seeds by gnawing through the cone scales, whereas the crossbills get at the seeds by extracting them with their unusual crossed mandibles. In areas where there are squirrels, the lodgepole's cones are heavier, and have fewer seeds and thinner scales, making it more difficult for squirrels to get at the seeds. Conversely, where there are crossbills but no squirrels, the cones are lighter in construction, but have thicker scales, making it more difficult for crossbills to get at the seeds. The lodgepole's cones are in an evolutionary arms race with the two kinds of herbivore.{{cite web |title=Coevolution |url=https://evolution.berkeley.edu/evolibrary/article/evo_33 |publisher=University of California Berkeley |access-date=17 January 2017}} and the two following pages of the web article.

File:Drosophila.melanogaster.couple.2.jpg has been studied in Drosophila melanogaster (shown mating, male on right).]]

{{Main|Intraspecific competition|Interspecific competition}}

Both intraspecific competition, with features such as sexual conflict{{cite journal |doi=10.1098/rstb.2005.1785 |title=Sexual conflict over mating and fertilization: An overview |year=2006 |last1=Parker |first1=G. A. |journal=Philosophical Transactions of the Royal Society B: Biological Sciences |volume=361 |issue=1466 |pages=235–59 |pmid=16612884 |pmc=1569603}} and sexual selection,{{cite web|title=Biol 2007 - Coevolution|url=https://www.ucl.ac.uk/~ucbhdjm/courses/b242/Coevol/Coevol.html|publisher=University College, London|access-date=19 January 2017}} and interspecific competition, such as between predators, may be able to drive coevolution.{{cite journal |last1=Connell |first1=Joseph H. |s2cid=5576868 |title=Diversity and the Coevolution of Competitors, or the Ghost of Competition Past |journal=Oikos |date=October 1980 |volume=35 |issue=2 |pages=131–138 |doi=10.2307/3544421 |jstor=3544421|bibcode=1980Oikos..35..131C }}

Intraspecific competition can result in sexual antagonistic coevolution, an evolutionary relationship analogous to an arms race, where the evolutionary fitness of the sexes is counteracted to achieve maximum reproductive success. For example, some insects reproduce using traumatic insemination, which is disadvantageous to the female's health. During mating, males try to maximise their fitness by inseminating as many females as possible, but the more times a female's abdomen is punctured, the less likely she is to survive, reducing her fitness.{{cite journal |last1=Siva-Jothy |first1=M. T. |last2=Stutt |first2=A. D. |doi=10.1098/rspb.2002.2260 |title=A matter of taste: Direct detection of female mating status in the bedbug |journal=Proceedings of the Royal Society B: Biological Sciences |year=2003 |volume=270 |issue=1515 |pages=649–652 |pmid=12769466 |pmc=1691276 }}

File:Amegilla on long tube of Acanthus ilicifolius flower.jpg

The types of coevolution listed so far have been described as if they operated pairwise (also called specific coevolution), in which traits of one species have evolved in direct response to traits of a second species, and vice versa. This is not always the case. Another evolutionary mode arises where evolution is reciprocal, but is among a group of species rather than exactly two. This is variously called guild or diffuse coevolution. For instance, a trait in several species of flowering plant, such as offering its nectar at the end of a long tube, can coevolve with a trait in one or several species of pollinating insects, such as a long proboscis. More generally, flowering plants are pollinated by insects from different families including bees, flies, and beetles, all of which form a broad guild of pollinators which respond to the nectar or pollen produced by flowers.Juenger, Thomas, and Joy Bergelson. "Pairwise versus diffuse natural selection and the multiple herbivores of scarlet gilia, Ipomopsis aggregata." Evolution (1998): 1583–1592.{{cite book |last1=Gullan |first1=P. J. |last2=Cranston |first2=P. S. |date=2010 |title=The Insects: An Outline of Entomology |url=https://archive.org/details/insectsoutlineen00pjgu |url-access=limited |publisher=Wiley |edition=4th |isbn=978-1-118-84615-5 |pages=[https://archive.org/details/insectsoutlineen00pjgu/page/n315 291]–293}}{{cite journal |last1=Rader |first1=Romina |last2=Bartomeus |first2=Ignasi |display-authors=etal |title=Non-bee insects are important contributors to global crop pollination |journal=PNAS |date=2016 |volume=113 |issue=1 |doi=10.1073/pnas.1517092112 |pmid=26621730 |pmc=4711867 |pages=146–151 |bibcode=2016PNAS..113..146R|doi-access=free }}

{{main|Mosaic coevolution}}

Mosaic coevolution is a theory in which geographic location and community ecology shape differing coevolution between strongly interacting species in multiple populations. These populations may be separated by space and/or time. Depending on the ecological conditions, the interspecific interactions may be mutualistic or antagonistic.{{cite journal |last1=Thompson |first1=John N. |title=Coevolution: The Geographic Mosaic of Coevolutionary Arms Races |journal=Current Biology |date=24 December 2005 |volume=15 |issue=24 |pages=R992–R994 |doi=10.1016/j.cub.2005.11.046 |pmid=16360677 |s2cid=16874487 |doi-access=free |bibcode=2005CBio...15.R992T }} In mutualisms, both partners benefit from the interaction, whereas one partner generally experiences decreased fitness in antagonistic interactions. Arms races consist of two species adapting ways to "one up" the other. Several factors affect these relationships, including hot spots, cold spots, and trait mixing.{{cite journal |last1=Gomulkiewicz |first1=Richard |last2=Thompson |first2=John N. |last3=Holt |first3=Robert D. |last4=Nuismer |first4=Scott L. |last5=Hochberg |first5=Michael E. |title=Hot Spots, Cold Spots, and the Geographic Mosaic Theory of Coevolution. |journal=The American Naturalist |date=1 August 2000 |volume=156 |issue=2 |pages=156–174 |doi=10.1086/303382 |pmid=10856199 |bibcode=2000ANat..156..156G |s2cid=4442185 }} Reciprocal selection occurs when a change in one partner puts pressure on the other partner to change in response. Hot spots are areas of strong reciprocal selection, while cold spots are areas with no reciprocal selection or where only one partner is present. The three constituents of geographic structure that contribute to this particular type of coevolution are: natural selection in the form of a geographic mosaic, hot spots often surrounded by cold spots, and trait remixing by means of genetic drift and gene flow. Mosaic, along with general coevolution, most commonly occurs at the population level and is driven by both the biotic and the abiotic environment. These environmental factors can constrain coevolution and affect how far it can escalate.{{cite journal |last1=Anderson |first1=Bruce |last2=Johnson |first2=Steven D. |title=The Geographical Mosaic of Coevolution in a Plant–Pollinator Mutualism |journal=Evolution |date=2008 |volume=62 |issue=1 |pages=220–225 |doi=10.1111/j.1558-5646.2007.00275.x |pmid=18067570 |s2cid=8643749 |doi-access=free }}

Coevolution is primarily a biological concept, but has been applied to other fields by analogy.

{{See also|Evolutionary computation}}

Coevolutionary algorithms are used for generating artificial life as well as for optimization, game learning and machine learning.Potter M.; De Jong, K. (1995) Evolving Complex Structures via Cooperative Coevolution, Fourth Annual Conference on Evolutionary Programming, San Diego, California.Potter M. (1997) The Design and Computational Model of Cooperative Coevolution, PhD thesis, George Mason University, Fairfax, Virginia.{{cite journal |last1=Potter |first1=Mitchell A. |last2=De Jong |first2=Kenneth A. |title=Cooperative Coevolution: An Architecture for Evolving Coadapted Subcomponents |journal=Evolutionary Computation |date=2000 |volume=8 |issue=1 |pages=1–29 |doi=10.1162/106365600568086 |pmid=10753229 |citeseerx=10.1.1.134.2926 |s2cid=10265380}}Weigand, P.; Liles, W.; De Jong, K. (2001) An empirical analysis of collaboration methods in cooperative coevolutionary algorithms. Proceedings of the Genetic and Evolutionary Computation Conference.Weigand, P. (2003) An Analysis of Cooperative Coevolutionary Algorithms, PhD thesis, George Mason University, Fairfax, Virginia, 2003. Daniel Hillis added "co-evolving parasites" to prevent an optimization procedure from becoming stuck at local maxima.{{cite journal |last=Hillis |first=W. D. |year=1990 |title=Co-evolving parasites improve simulated evolution as an optimization procedure |journal=Physica D: Nonlinear Phenomena |volume=42 |issue=1–3 |pages=228–234 |doi=10.1016/0167-2789(90)90076-2|bibcode=1990PhyD...42..228H}} Karl Sims coevolved virtual creatures.{{cite web |last=Sims |first=Karl |title=Evolved Virtual Creatures |url=http://www.karlsims.com/evolved-virtual-creatures.html|publisher=Karl Sims |access-date=17 January 2017 |date=1994}}

The concept of coevolution was introduced in architecture by the Danish architect-urbanist Henrik Valeur as an antithesis to "star-architecture".{{cite web |url=http://henrikvaleur.dk/biography/ |title=Henrik Valeur's biography |access-date=2015-08-29}} As the curator of the Danish Pavilion at the 2006 Venice Biennale of Architecture, he created an exhibition-project on coevolution in urban development in China; it won the Golden Lion for Best National Pavilion.{{cite web |url=http://www.dac.dk/en/dac-life/exhibitions/2006/co-evolution/about-co-evolution/ |title=About Co-evolution |publisher=Danish Architecture Centre |access-date=2015-08-29 |url-status=dead |archive-url=https://web.archive.org/web/20151120011414/http://www.dac.dk/en/dac-life/exhibitions/2006/co-evolution/about-co-evolution/ |archive-date=2015-11-20 }}{{cite web |url=https://movingcities.org/interviews/henrik-valeur_domuschina/ |title= An interview with Henrik Valeur |publisher=Movingcities |access-date=2015-10-17 |date=2007-12-17}}{{cite book |last=Valeur |first=Henrik |title=Co-evolution: Danish/Chinese Collaboration on Sustainable Urban Development in China|publisher=Danish Architecture Centre|year= 2006|location= Copenhagen |isbn=978-87-90668-61-7 |page=12}}{{cite book |last=Valeur |first=Henrik |title=India: the Urban Transition - a Case Study of Development Urbanism |publisher=Architectural Publisher B |year=2014 |isbn=978-87-92700-09-4 |title-link=India: the Urban Transition |page=22}}

At the School of Architecture, Planning and Landscape, Newcastle University, a coevolutionary approach to architecture has been defined as a design practice that engages students, volunteers and members of the local community in practical, experimental work aimed at "establishing dynamic processes of learning between users and designers."{{cite journal |last=Farmer |first=Graham |year=2017 |title=From Differentiation to Concretisation: Integrative Experiments in Sustainable Architecture |journal=Societies |volume=3 |issue=35 |page=18 |doi=10.3390/soc7040035 |doi-access=free }}

In his book The Self-organizing Universe, Erich Jantsch attributed the entire evolution of the cosmos to coevolution.

In astronomy, an emerging theory proposes that black holes and galaxies develop in an interdependent way analogous to biological coevolution.{{cite journal |last=Gnedin |first=Oleg Y. |display-authors=etal|title=Co-Evolution of Galactic Nuclei and Globular Cluster Systems |journal=The Astrophysical Journal |volume=785 |issue=1 |doi=10.1088/0004-637X/785/1/71 |bibcode=2014ApJ...785...71G |pages=71|arxiv=1308.0021|year=2014 |s2cid=118660328 }}

Since year 2000, a growing number of management and organization studies discuss coevolution and coevolutionary processes. Even so, Abatecola el al. (2020) reveals a prevailing scarcity in explaining what processes substantially characterize coevolution in these fields, meaning that specific analyses about where this perspective on socio-economic change is, and where it could move toward in the future, are still missing.{{cite journal |doi=10.1016/j.techfore.2020.119964 |title=Do organizations really co-evolve? Problematizing co-evolutionary change in management and organization studies |year=2020 |journal=Technological Forecasting and Social Change |volume= 155 |last1=Abatecola |first1=Gianpaolo |last2=Breslin |first2=Dermot |last3=Kask |first3=Johan |page=119964 |issn=0040-1625|doi-access=free }}

In Development Betrayed: The End of Progress and A Coevolutionary Revisioning of the Future (1994){{cite book |last=Norgaard |first=Richard B. |title=Development Betrayed: The End of Progress and a Coevolutionary Revisioning of the Future |year=1994 |publisher=Routledge}} Richard Norgaard proposes a coevolutionary cosmology to explain how social and environmental systems influence and reshape each other.{{cite journal |last1=Glasser |first1=Harold |year=1996 |title=Development Betrayed: The End of Progress and A Coevolutionary Revisioning of the Future by Richard B. Norgaard |journal=Environmental Values |volume=5 |issue=3 |pages=267–270|doi=10.1177/096327199600500308 |jstor=30301478 |s2cid=259156528 }} In Coevolutionary Economics: The Economy, Society and the Environment (1994) John Gowdy suggests that: "The economy, society, and the environment are linked together in a coevolutionary relationship".{{cite book |last=Gowdy |first=John |title=Coevolutionary Economics: The Economy, Society and the Environment |year=1994 |publisher=Springer |pages=1–2}}

{{Further|Software ecosystem}}

Computer software and hardware can be considered as two separate components but tied intrinsically by coevolution. Similarly, operating systems and computer applications, web browsers, and web applications. All these systems depend upon each other and advance through a kind of evolutionary process. Changes in hardware, an operating system or web browser may introduce new features that are then incorporated into the corresponding applications running alongside.{{cite book |last1=D’Hondt |first1=Theo |last2=Volder |first2=Kris |last3=Mens |first3=Kim |last4=Wuyts |first4=Roel |title=Software Architectures and Component Technology |chapter=Co-Evolution of Object-Oriented Software Design and Implementation |publisher=Springer US |publication-place=Boston, MA |year=2002 |isbn=978-1-4613-5286-0 |doi=10.1007/978-1-4615-0883-0_7 |pages=207–224}} The idea is closely related to the concept of "joint optimization" in sociotechnical systems analysis and design, where a system is understood to consist of both a "technical system" encompassing the tools and hardware used for production and maintenance, and a "social system" of relationships and procedures through which the technology is tied into the goals of the system and all the other human and organizational relationships within and outside the system. Such systems work best when the technical and social systems are deliberately developed together.{{cite journal |last1=Cherns |first1=A. |year=1976 |title=The principles of sociotechnical design |journal=Human Relations |volume=29 |issue=8 |page=8 |doi=10.1177/001872677602900806 |doi-access= }}

• Evolutionary arms race
• Bak–Sneppen model
• CoEvolution Quarterly
• Coextinction
• Ecological fitting
• Escape and radiate coevolution
• Genomics of domestication

{{Notelist}}

{{Reflist}}

• [http://www.cosmolearning.com/video-lectures/coevolution-6703/ Coevolution], video of lecture by Stephen C. Stearns (Open Yale Courses)

{{Evolution}}

{{Evolutionary psychology}}

Category:Ecological processes

Category:Environmental terminology

Category:Evolution of the biosphere

Category:Evolutionary biology

Category:Habitat