User:Quesedillon/Pair bond

Article Lead

 * Brief description of the article's major sections such as: types of varieties, examples of human and animal pair bonding
 * Brief information about unique characteristics, sexual, social, and cognitive abilities that relate to pair-bonding
 * Brief information about how it plays a major role in reproduction and species survival

Article Draft

 * Mention types of mammals that display specific types of bond
 * Introduce types of hormone and neurotransmitters and the biological factors that affect pair bonds
 * Briefly mention the science and future directions of pair-bonding
 * Illustrate more information under human pair bonding, specifically behavioural, physiological, and biological factors affect how pair-bonding is determined

Human
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. Humans also engage in social pair bonding, where two individuals will form a close relationship that does not involve sex. In humans and other vertebrates, pair bonds are created by a combination of social interaction and biological factors including neurotransmitters like oxytocin, vasopressin, and dopamine.

Pair bonds are a biological phenomenon and are not equivalent to the human social institution of 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.

In humans, pair bonds began as a means to divide the costs of raising children due to their delayed maturity and larger brain.

Voles
Pair bonding, specifically social monogamy, is rare in mammals because there is higher reproductive success by mating with multiple females rather than investing parental time with a single female. Additionally, pair bonds is assessed by the degree of proximity and affiliation between pair mates which varies between pair-living species. Some species are dispersed, meaning they share a common territory but rarely interact, while other species having permanent association. Pair bonds in mammals are regularly associated with mate-guarding and bi-parental care of young. This suggest that pair bonding became an adaptation to ensure successful offspring survival.

Prairie voles form long-lasting socially monogamous bonds which are not common in other vole species, such as meadow voles and montane voles. This social behaviour is associated with a greater density and distribution of vasopressin, dopamine, and oxytocin receptors found in areas of the brain associated with reward and addiction. These hormones act in the regions that help coordinate rewarding activities such as mating, which facilitates the development of pair bonds.

When compared to montane voles, which are polygamous, monogamous prairie voles appear to have more of vasopressin and oxytocin neurotransmitter receptors. The regions rich in these receptors are also rich in dopamine, resulting in conditioned partner preference in prairie voles. Partner preference is correlated with the expression levels of vasopressin receptors in the reward center of the brain, which may explain the socially monogamous behaviour of prairie voles. In a study, montane voles were injected with exogenous vasopressin to induce partner preference resulting in no preference formation. This suggest that that vasopressin alone is not responsible for different social behaviours.

Another socially monogamous rodent is the mandarin vole, which were used to study the effects of pair bond in regulating emotion and behaviour. Mandarin voles showed anxiety- and depression-like behaviours when separated from their partners and housed alone for two-weeks. The results also indicate a sex difference in responses since male voles had higher anxiety- and depression-like behaviours than their female partners. This suggests that pair bond interruption may increase stress response.

Birds

 * do more research on the European pied flycatcher (polygyny)
 * Macaw
 * Swans - nesting failure will lead to moving on
 * Swans - nesting failure will lead to moving on

Fish

 * do more research into sand gobies relationships

Pair bonding may also have non-reproductive benefits, such as assisted resource defense. Recent study comparing two species of butterflyfishes, C. baronessa and C. lunulatus, indicate increase in food and energy reserves compared to individual fish. However, there is limited research on the advantages of long-term pair bonding and increase fitness