View source for Philosophy:Pair bond

{{short description|Biological term}}
[[File:Two Gannets edit 2.jpg|thumb|240px|Northern gannet pair]]
In [[Biology:Biology|biology]], a '''pair bond''' is the strong affinity that develops in some [[Biology:Species|species]] between a mating pair, often leading to the production and rearing of young and potentially a lifelong bond. Pair-bonding is a term coined in the 1940s<ref>{{Cite encyclopedia | entry = Pair-bond | year = 2005 | work= Oxford English Dictionary | url = https://www.oed.com/view/Entry/246982| title = Home : Oxford English Dictionary }}</ref> that is frequently used in [[Philosophy:Sociobiology|sociobiology]] and [[Biology:Evolutionary biology|evolutionary biology]] circles. The term often implies either a lifelong [[Biology:Monogamy in animals|socially monogamous]] relationship or a stage of mating interaction in socially monogamous species. It is sometimes used in reference to human relationships.

==Varieties==
[[File:Schakale Kreuzkap 02.jpg|thumb|[[Biology:Black-backed jackal|Black-backed jackal]]s are one of very few monogamous mammals. This pair uses teamwork to hunt down prey and scavenge. They will stay together until one of the two dies.]]
According to evolutionary psychologists [[Biography:David P. Barash|David P. Barash]] and Judith Lipton, from their 2001 book ''The Myth of Monogamy'', there are several varieties of pair bonds:<ref name=Barash>{{cite book | vauthors = Barash D, Lipton J |title=The Myth of Monogamy: Fidelity and Infidelity in Animals and People |publisher=Henry Holt and Company |location=New York |year=2001 |isbn=978-0805071368}}</ref>
*''Short-term pair-bond:'' a transient mating or associations
*''Long-term pair-bond:'' bonded for a significant portion of the life cycle of that pair
*''Lifelong pair-bond:'' mated for life
*''Social pair-bond:'' attachments for territorial or social reasons
*''Clandestine pair-bond:'' quick [[Biology:Extra-pair copulation|extra-pair copulation]]s
*''Dynamic pair-bond'': e.g. [[Biology:Gibbon|gibbon]] mating systems being analogous to "[[Social:Divorce|divorce]]"

==Human pair bonding==
[[File:Юноша ухаживает за девушкой.jpg|right|thumb|Pair-bonded human male and female]]
Humans can experience all of the above-mentioned varieties of pair bonds. These bonds can be temporary or last a lifetime. Pair bonding is a behavioral and physiological bond between two mated individuals, and is rare among non-human primates.<ref name=":0">{{Cite book|chapter=Social Pair-Bonding and Resource Defense in Wild Red-Bellied Lemurs (Eulemur rubriventer)|doi=10.1007/978-0-387-34586-4_11 | title = Lemurs |series=Developments in Primatology: Progress and Prospect |year=2006 | vauthors = Overdorff DJ, Tecot SR |pages=235–254|isbn=978-0-387-34585-7}}</ref> Humans also engage in social pair bonding, where two individuals will form a close relationship that does not involve sex.<ref name=":1" /> In humans and other [[Biology:Vertebrate|vertebrates]], pair bonds are created by a combination of social interaction and biological factors including [[Biology:Neurotransmitter|neurotransmitter]]s like [[Chemistry:Oxytocin|oxytocin]], [[Biology:Vasopressin|vasopressin]], and [[Biology:Dopamine|dopamine]].<ref name=":1" /><ref>{{Cite thesis | vauthors = Garcia C | degree = PhD | date = May 2019 | publisher = Winthrop University |title=The Role of Oxytocin on Social Behavior Associated with the Formation of a Social Pair-Bond in the Socially Monogamous Convict Cichlid (Amatitlania nigrofasciata) |url= https://digitalcommons.winthrop.edu/graduatetheses/99/ }}</ref>

Pair bonds are a biological phenomenon and are not equivalent to the human social institution of [[Biology:Marriage|marriage]]. Married couples are not necessarily pair bonded. Marriage may be a consequence of pair bonding and vice versa. One of the functions of romantic love is pair bonding.<ref>{{cite journal | vauthors = Bode A, Kushnick G | title = Proximate and Ultimate Perspectives on Romantic Love | language = English | journal = Frontiers in Psychology | volume = 12 | pages = 573123 | date = 2021 | pmid = 33912094 | pmc = 8074860 | doi = 10.3389/fpsyg.2021.573123 | doi-access = free }}</ref><ref name=":1">{{cite web | vauthors = Fuentes A | date = 9 May 2012 |url=http://www.psychologytoday.com/blog/busting-myths-about-human-nature/201205/marriage-and-pair-bonds|title=On Marriage and Pair Bonds|website=Psychology Today|access-date=24 April 2018}}</ref>

==Examples==
===Birds===
Close to ninety percent<ref name = "Young_2003">{{cite book | vauthors = Young LJ  | chapter = The Neural Basis of Pair Bonding in a Monogamous Species: A Model for Understanding the Biological Basis of Human Behavior | chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK97287/ | veditors = Wachter KW, Bulatao RA | title = Offspring: Human Fertility Behavior in Biodemographic Perspective. |date= 2003 | location = Washington (DC) |publisher=National Academies Press (US) | isbn = 978-0-309-08718-6 |access-date=11 June 2018 |via=www.ncbi.nlm.nih.gov|url-status=live|archive-url=https://web.archive.org/web/20180206104328/https://www.ncbi.nlm.nih.gov/books/NBK97287/|archive-date=6 February 2018}}</ref> of known avian species are [[Biology:Monogamy in animals|monogamous]], compared to five percent of known mammalian species. The majority of monogamous avians form long-term pair bonds which typically result in seasonal mating: these species breed with a single partner, raise their young, and then pair up with a new mate to repeat the cycle during the next season. Some avians such as [[Biology:Swan|swan]]s, [[Biology:Bald eagle|bald eagle]]s, [[Biology:California condor|California condor]]s, and the Atlantic Puffin are not only monogamous, but also form lifelong pair bonds.<ref>{{cite web | vauthors = Berger M | date = 10 February 2012 |url= https://www.audubon.org/news/till-death-do-them-part-8-birds-mate-life/|title= Till Death do them Part: 8 Birds that Mate for Life |publisher=National Audubon Society |access-date=11 June 2018 }}</ref> 

When discussing the social life of the bank swallow, Lipton and Barash state:<ref name=Barash/>

<blockquote>
For about four days immediately prior to egg-laying, when copulations lead to fertilization, the male bank swallow is very busy, attentively guarding his female. Before this time, as well as after—that is, when her eggs are not ripe, and again after his genes are safely tucked away inside the shells—he goes seeking extra-pair copulations with the mates of other males…who, of course, are busy with defensive mate-guarding of their own.
</blockquote>
[[File:Mallard ducks pair.jpeg|thumb|Male (left) and female (right) [[Biology:Mallard|mallard ducks]] form seasonal monogamous pairs.]]
In various species, males provide parental care and females mate with multiple males. For example, recent studies show that extra-pair copulation frequently occurs in monogamous birds in which a "social" father provides intensive care for its "social" offspring.<ref name="Wakano_2005">{{cite journal | vauthors = Wakano JY, Ihara Y | title = Evolution of male parental care and female multiple mating: game-theoretical and two-locus diploid models | journal = The American Naturalist | volume = 166 | issue = 2 | pages = E32–44 | date = August 2005 | pmid = 16032569 | doi = 10.1086/431252 | s2cid = 23771617 }}; {{Lay source |url=https://www.sciencedaily.com/releases/2005/07/050727060446.htm |title=New Study Explores The Evolution Of Male Parental Care And Female Multiple Mating |work=ScienceDaily |url-status=live |archive-url=https://web.archive.org/web/20150905201104/http://www.sciencedaily.com/releases/2005/07/050727060446.htm |archive-date=2015-09-05 }}</ref> Furthermore, it was observed that newly formed pair bonds in biparental plovers were comparatively weaker than those in uniparental plovers.<ref>{{Cite journal |last1=Parra |first1=Jorge E. |last2=Beltrán |first2=Marcela |last3=Zefania |first3=Sama |last4=Dos Remedios |first4=Natalie |last5=Székely |first5=Tamás |date=2014-04-01 |title=Experimental assessment of mating opportunities in three shorebird species |url=https://researchportal.bath.ac.uk/files/40316095/Parra_et_al_revised_FINAL.pdf |journal=Animal Behaviour |volume=90 |pages=83–90 |doi=10.1016/j.anbehav.2013.12.030 |s2cid=15727544 |issn=0003-3472}}</ref>

===Fish===
A [[Organization:University of Florida|University of Florida]] scientist reports that male sand [[Biology:Goby|gobies]] work harder at building nests and taking care of eggs when females are present – the first time such "courtship parental care" has been documented in any species.<ref>{{cite journal | vauthors = Pampoulie C, Lindström K, St Mary CM | title = Have your cake and eat it too: male sand gobies show more parental care in the presence of female partners. | journal = Behavioral Ecology | date = March 2004 | volume = 15 | issue = 2 | pages = 199–204 | doi = 10.1093/beheco/arg107 | doi-access = free }}; {{lay source |url=https://www.sciencedaily.com/releases/2004/05/040505064746.htm |title=For A Male Sand Goby, Playing 'Mr. Mom' Is Key To Female's Heart |work=ScienceDaily |url-status=live |archive-url=https://web.archive.org/web/20160305011749/https://www.sciencedaily.com/releases/2004/05/040505064746.htm |archive-date=2016-03-05 }}</ref>

In the cichlid species ''[[Biology:Tropheus moorii|Tropheus moorii]]'', a male and female will form a temporary monogamous pair bond and spawn; after which, the female leaves to mouthbrood the eggs on her own. ''T. moorii'' broods exhibit genetic monogamy (all eggs in a brood are fertilized by a single male).<ref name=":3">{{cite journal | vauthors = Steinwender B, Koblmüller S, Sefc KM | title = Concordant female mate preferences in the cichlid fish ''Tropheus moorii''. | journal = Hydrobiologia | volume = 682 | issue = 1 | pages = 121–130 | date = February 2012 | pmid = 24293682 | pmc = 3841713 | doi = 10.1007/s10750-011-0766-5 }}</ref> Another mouth brooding cichlid – the Lake Tanganyika cichlid (''Xenotilapia rotundiventralis'') has been shown that mating pairs maintain pair bonds at least until the shift of young from female to male.<ref>{{cite journal | vauthors = Takahashi T, Ochi H, Kohda M, Hori M | title = Invisible pair bonds detected by molecular analyses | journal = Biology Letters | volume = 8 | issue = 3 | pages = 355–357 | date = June 2012 | pmid = 22114323 | pmc = 3367736 | doi = 10.1098/rsbl.2011.1006 }}</ref> More recently the Australian [[Biology:Murray cod|Murray cod]] has been seen maintaining pair bonds over 3 years.<ref>{{cite journal | vauthors = Couch AJ, Dyer F, Lintermans M | title = Multi-year pair-bonding in Murray cod (''Maccullochella peelii'') | journal = PeerJ | volume = 8 | pages = e10460 | date = 2020 | pmid = 33354425 | pmc = 7733648 | doi = 10.7717/peerj.10460 | doi-access = free }}</ref>

Pair bonding may also have non-reproductive benefits, such as assisted resource defense.<ref>{{cite journal | vauthors = Bales KL, Ardekani CS, Baxter A, Karaskiewicz CL, Kuske JX, Lau AR, Savidge LE, Sayler KR, Witczak LR | display-authors = 6 | title = What is a pair bond? | journal = Hormones and Behavior | volume = 136 | pages = 105062 | date = November 2021 | pmid = 34601430 | doi = 10.1016/j.yhbeh.2021.105062 | s2cid = 238234968 | doi-access = free }}</ref> Recent study comparing two species of butterflyfishes, ''[[Biology:Eastern triangle butterflyfish|C. baronessa]]'' and ''[[Biology:Oval butterflyfish|C. lunulatus]]'', indicate increase in food and energy reserves compared to individual fish.<ref>{{cite journal | vauthors = Nowicki JP, Walker SP, Coker DJ, Hoey AS, Nicolet KJ, Pratchett MS | title = Pair bond endurance promotes cooperative food defense and inhibits conflict in coral reef butterflyfish | journal = Scientific Reports | volume = 8 | issue = 1 | pages = 6295 | date = April 2018 | pmid = 29674741 | pmc = 5908845 | doi = 10.1038/s41598-018-24412-0 | bibcode = 2018NatSR...8.6295N }}</ref> However, there is limited research on the advantages of long-term pair boding and increased fitness.

===Mammals===
Monogamous [[Biology:Vole|vole]]s (such as prairie voles) have significantly greater density and distribution of [[Biology:Vasopressin|vasopressin]] receptors in their brain when compared to polygamous voles. These differences are located in the ventral forebrain and the dopamine-mediated reward pathway.

Peptide arginine [[Biology:Vasopressin|vasopressin]] (AVP), [[Biology:Dopamine|dopamine]], and [[Chemistry:Oxytocin|oxytocin]] act in this region to coordinate rewarding activities such as mating, and regulate selective affiliation. These species-specific differences have shown to correlate with social behaviors, and in monogamous prairie voles are important for facilitation of pair bonding. When compared to [[Biology:Montane vole|montane vole]]s, which are [[Biology:Animal sexual behaviour#Polygamy|polygamous]], [[Biology:Monogamy in animals|monogamous]] [[Biology:Prairie vole|prairie vole]]s appear to have more of these AVP and oxytocin [[Biology:Neurotransmitter receptor|neurotransmitter receptor]]s. It is important that these receptors are in the reward centers of the brain because that could lead to a ''conditioned'' partner preference in the prairie vole compared to the montane vole which would explain why the prairie vole forms pair bonds and the montane vole does not.<ref name = "Young_2003" /><ref name="Lim 2004">{{cite journal | vauthors = Lim MM, Wang Z, Olazábal DE, Ren X, Terwilliger EF, Young LJ | title = Enhanced partner preference in a promiscuous species by manipulating the expression of a single gene | journal = Nature | volume = 429 | issue = 6993 | pages = 754–757 | date = June 2004 | pmid = 15201909 | doi = 10.1038/nature02539 | s2cid = 4340500 | bibcode = 2004Natur.429..754L }}</ref>

As noted above, different species of voles vary in their sexual behavior, and these differences correlate with expression levels of vasopressin receptors in reward areas of the brain. Scientists were able to change adult male montane voles' behavior to resemble that of monogamous prairie voles in experiments in which vasopressin receptors were introduced into the brain of male montane voles.{{Citation needed|date=January 2018}}

== See also ==
*[[Philosophy:Affectional bond|Affectional bond]]
*[[Philosophy:Attachment theory|Attachment theory]]
*Animal sexuality
*[[Biology:Breeding pair|Breeding pair]]
*[[Philosophy:Human bonding|Human bonding]]
*Monogamous pairing in animals
*[[Social:Monogamy|Monogamy]]
*r/K selection theory

== References ==
{{reflist|30em}}

== Further reading ==
{{refbegin}}
* {{cite journal | vauthors = Young LJ, Wang Z | title = The neurobiology of pair bonding | journal = Nature Neuroscience | volume = 7 | issue = 10 | pages = 1048–1054 | date = October 2004 | pmid = 15452576 | doi = 10.1038/nn1327 | s2cid = 894249 }}
{{refend}}

== External links ==

{{Evolutionary psychology}}

[[Category:Ethology]]
[[Category:Evolutionary psychology]]

{{Sourceattribution|Pair bond}}