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With apologies, an incorrect author list was given in the article. An additional author, Chris von Rueden, (Jepson School of Leadership Studies, University of Richmond) also contributed to this work. Author Ryan Schacht's affiliation was out-of-date. His correct affiliation is: Department of Anthropology, East Carolina University.

Monogamy appears to have become the predominant human mating system with the emergence of highly unequal agricultural populations that replaced relatively egalitarian horticultural populations, challenging the conventional idea-based on the polygyny threshold model-that polygyny should be positively associated with wealth inequality. To address this polygyny paradox, we generalize the standard polygyny threshold model to a mutual mate choice model predicting the fraction of women married polygynously. We then demonstrate two conditions that are jointly sufficient to make monogamy the predominant marriage form, even in highly unequal societies. We assess if these conditions are satisfied using individual-level data from 29 human populations. Our analysis shows that with the shift to stratified agricultural economies: (i) the population frequency of relatively poor individuals increased, increasing wealth inequality, but decreasing the frequency of individuals with sufficient wealth to secure polygynous marriage, and (ii) diminishing marginal fitness returns to additional wives prevent extremely wealthy men from obtaining as many wives as their relative wealth would otherwise predict. These conditions jointly lead to a high population-level frequency of monogamy.

For altricial mammalian species, early life social bonds are constructed principally between offspring and their mothers, and the mother-offspring relationship sets the trajectory for offspring bio-behavioral development. In the rare subset of monogamous and biparental species, offspring experience an expanded social network which includes a father. Accordingly, in biparental species fathers also have the potential to influence trajectories of offspring development. Previous semi-natural and laboratory study of one monogamous and biparental species, the prairie vole (Microtus ochrogaster), has given insight into the role that mothers and fathers play in shaping behavioral phenotypes of offspring. Of particular interest is the influence of biparental care in the development of monogamous behavior in offspring. Here, we first briefly review that influence. We then present novel research which describes how parental investment in prairie voles changes across sequential litters of pups, and the extent to which it is coordinated between mothers and fathers. We use approximately 6 years of archival data on prairie vole parenting to investigate trajectories and inter-parent dynamics in prairie vole parenting. We use a series of latent growth models to assess the stability of parental investment across the first 4 l. Our findings suggest that prairie voles display sexually dimorphic patterns of change in parental behavior: mothers' investment declines linearly whereas fathers' pattern of change is characterized by initial decline between litters 1 and 2 with subsequent increase from litters 2 to 4. Our findings also support a conclusion that prairie vole paternal care may be better characterized as compensatory-that is, fathers may compensate for decline in maternal investment. Opposing trends in investment between mothers and fathers ultimately imply stability in offspring investment across sequential litters. These findings, combined with previous studies, generate a hypothesis that paternal compensation could play an important role in maintaining the development of monogamous behavioral phenotypes in individual offspring and across cohorts of those offspring. Understanding longitudinal and inter-individual dynamics of complex social behaviors is critical for the informed investigation of both proximate and ultimate mechanisms that may subserve these behaviors.

Highly valued food items are often used as rewards to reinforce an animal's behavior. For social species, social interaction is rewarding and can drive an individual's behavior as well. In the currently study, we wanted to compare the efficacy of a food reward and a social reward on object discrimination learning in socially monogamous titi monkeys. We hypothesized that titi monkeys would perform more accurately for a social reward (their pair mate) than for a food reward (a highly desired food item). Eleven adult titi monkeys were tested with a two-object visual discrimination task for both types of reward. The colors and shapes of the objects in the two-object discrimination task were counterbalanced across subjects. During each trial, subjects were shown two objects, and the trial ended when the subject touched the reinforced shape (S+) or after 5 min. A correct trial was defined as one when the subject touched S+ first. We found that 45.5% of subjects were able to learn the task with a social reward, and 83.3% were able to learn the task with a food reward. We found that subjects balked more often and had fewer correct trials for the social reward. Finally, subjects took longer to approach the shapes for a social reward, possibly indicating lower motivation to engage in the task when a social reward is used compared to a food reward. Although significantly fewer subjects met criteria of success with the social reward than with the food reward, our results show that titi monkeys can learn a visual discrimination task with either type of reward.

Genetic monogamy is rare-at least at the level of a species-and monogamy can exist in the absence of sexual fidelity. Rather than focusing on mating exclusivity, it has become common to use the term "social monogamy" to describe a cluster of social features, including the capacity for selective and lasting social bonds, central to what humans call "love." Socially monogamous mammals often exhibit selective aggression toward strangers and form extended families. These features of social monogamy in mammals are supported by patterns of hormonal function originating in the neurobiology of maternity, including oxytocin, as well as a more primitive vasopressin pathway. Another key feature of social monogamy is reduced sexual dimorphism. Processes associated with sexual differentiation offer clues to the mysteries surrounding the evolution of monogamy. Although there is consistency in the necessary ingredients, it is likely that there is no single recipe for social monogamy. As reviewed here, genes for steroids and peptides and their receptors are variable and are subject to epigenetic regulation across the lifespan permitting individual, gender and species variations and providing substrates for evolution. Reduced sensitivity to gonadal androgens, and a concurrent increased reliance on vasopressin (for selective defense) and oxytocin (for selective affiliation) may have offered pathways to the emergence of social monogamy.

Maqashidi interpretation is able to provide new breakthroughs in the approach to understanding the Qur'an. The development of this study continues to be of interest. Maqashidi interpretation as a philosophy of interpretation will give a new spirit, not only in the product of the interpretation of the Qur'an, but also in the process of interpretation. The term maqashidi is not a new term because it was previously used in relation to shari'ah (maqashid as-Shari'ah). This is very much in accordance with the statement of the Qur'an which is pious kulli zaman wa makan. Maqashidi interpretation is generally used in interpreting legal verses. In this article, we discuss two focuses. First, how is the commentator's interpretation of the QS. An-Nisa'[4] verse 3, 128-130. Second, how is the application and analysis of maqashidi interpretation in QS. An-Nisa'[4] verses 128-130. The method that the author uses is the thematic method, which is discussing the verses based on a set theme. Aims to gain a focused understanding of the reinterpretation of polygamous verses with a review of maqashidi interpretations. This article is expected to be able to contribute to the Indonesian Muslim community in understanding the verses about the law contained in this polygamy and monogamy theme.

Although several hypotheses have been proposed to explain the emergence of social monogamy, its origin is still intensely debated. Monogamy has many potential drivers, but evolutionary causality among them remains unclear. Using phylogenetic comparative methods within a Bayesian framework we explored the evolution of monogamy in cichlids and in marine reef fishes because, while both groups are characterised by unusually high incidence of social monogamy, they face very different ecological challenges. For each group, we examined four classic hypotheses that explain the evolution of monogamy: female dispersal, male mate guarding, female–female intolerance, and the biparental care hypotheses. We also explored whether the ecological traits of diet and shelter use are evolutionarily coupled with these hypotheses or with monogamy. First, we found that the evolution of monogamy was predicted by male territoriality in cichlids and simultaneous male and female territoriality in marine reef fishes. We suggest that these results provide support for the male mate guarding hypothesis in cichlids and female–female intolerance hypothesis in marine reef fishes. Second, we demonstrate clear evidence against the biparental care hypothesis, as biparental care was a consequence, not a cause, of monogamy in our analyses. Third, as female dispersal drove the loss of monogamy in both cichlids and marine reef fishes, this suggests the female dispersal hypothesis is not driving the evolution of monogamy in either group. These findings in two highly-monogamous fish taxa largely support prior findings from primate and bird comparative studies and provide novel large-scale evidence for a link between mate guarding and the evolution of monogamy.

Despite widespread interest in the evolution and implications of monogamy across taxa, less attention—especially theoretical—has been paid toward understanding the evolution of divorce (ending a socially monogamous pairing to find a new partner). Here, we develop a model of the evolution of divorce by females in a heterogeneous environment, where females assess territory quality as a result of their breeding success. Divorce results in females leaving poor territories disproportionally more often than good territories, while death of a partner occurs independent of territory quality, giving an advantage to divorce. Increasing environmental heterogeneity, a decreasing benefit of pair experience, and moderate survival rates favor the evolution of higher divorce rates, even in the absence of variance in individual quality and knowledge of available territories. Imperfect information about territory quality constrains the evolution of divorce, typically favoring divorce strategies that remain faithful to one's partner whenever successful reproduction occurs. Our model shows how feedbacks between divorce, widowhood, and the availability of territories are intricately linked in determining the evolutionary advantage of divorce. We detail testable predictions about populations that should be expected to divorce at high rates. [ABSTRACT FROM AUTHOR]

Animal populations can present different mating tactics according to the number of mates males or females obtain. The limiting factors for copulation in symbiont crustaceans are the size, structural complexity, and density of refuge, in addition to predation risk outside their shelters. In this study, we aimed to investigate, comparatively, if the occupation of the same refuge leads to the same reproductive tactic in two symbiont species of alpheid shrimps. For this purpose, we described the population distribution of Alpheus estuariensis, a burrowing shrimp, and Salmoneus carvachoi, a tenant species, in an intertidal mudflat in Pernambuco, northeastern Brazil. Alpheus estuariensis experiences sexual dimorphism relative to body and cheliped size, where males present larger body sizes and allocate more resources to cheliped growth than females. However, both males and females presented positive allometric growth in chelipeds. In S. carvachoi, male‐phase individuals reach smaller body sizes than hermaphrodites. Male‐phase shrimps experience positive allometry in cheliped size, while hermaphrodites do not. Both species were found inhabiting burrows as sexual pairs more frequently than expected by chance. Paired females of A. estuariensis were found carrying embryos more frequently than solitary ones. We did not find a statistical difference between the frequency of single and paired ovigerous hermaphrodites in S. carvachoi. Our results indicate that A. estuariensis is social monogamous, while S. carvachoi is promiscuous. We argue that different biological and ecological aspects of these species could explain the distinct tactics adopted by them. Alpheus estuariensis digs its own refuge and is a much larger species, bearing a more robust cheliped than S. carvachoi. Thus, we argue that the burrowing species (A. estuariensis) should monopolize and defend their refuge, and S. carvachoi only takes advantage of this resource. [ABSTRACT FROM AUTHOR]

Coppery titi monkeys maintain pair bonds through affiliative behaviours (e.g. tail twining, maintaining social proximity). Findings from previous studies suggest that the amount of time pairs spend in affiliative contact is not stable over time within pairs and differs across pairs. The present study investigates several predictors (temperament, age at pairing, pregnancy status and presence of infant) that may help explain observed changes in affiliation over time and between pairs. We hypothesized that affiliation varies for individual dyads and that time-varying and dyad level predictors explain variability in affiliation. We analysed pair affiliation using scan samples collected five times per day for 1 year for 29 pairs. We used Bayesian nonlinear mixed-effects effects modelling to test the effects of predictors. Pregnancy predicted higher affiliation levels (ϒ 02 = 0.40, 95% highest posterior density interval (HPDI): [0.21, 0.58]). The presence of an infant and aggression did not predict variability in affiliation. Models would not converge when we included age at pairing, so we cannot draw conclusions about the role of age in affiliation. Findings from this study suggest that time-varying predictors like pregnancy status help explain the large degree of variability observed in affiliative interactions between partners in this species. It is possible that hormonal changes associated with pregnancy are driving changes in affiliative behaviours in pairs. An alternative explanation is that pairs that are more affiliative to begin with are more likely to get pregnant. Future studies will assess whether these patterns persist in subsequent pairings. • Titi monkey dyads varied in their levels of affiliation. • Pregnancy predicted higher levels of affiliation. • Aggression and infant presence did not significantly explain affiliation patterns. • Effect of age at pairing could not be evaluated using our models. [ABSTRACT FROM AUTHOR]

Mating systems, and individual mating tactics therein, are regularly defined by patterns of space use and are inherent reflections of spatial cognition. Despite this, spatial learning is rarely considered in the context of mating tactics. The goal of this study was to determine the relationship between spatial learning and the mating tactics that males adopt. Specifically, we asked whether spatial learning predicts the adoption of a particular tactic, whether the adoption of a particular tactic results in differences in spatial learning and/or whether individual variance in spatial learning is flexible or persistent across time and mating tactic experiences. To this end, we assessed spatial learning of male prairie voles, Microtus ochrogaster , under laboratory conditions before and after allowing them to live freely in seminatural field enclosures. Male prairie voles adopt two types of mating tactics, each with distinct patterns of space use. Monogamous 'resident' males have relatively small home ranges and exhibit high degrees of territory overlap with one female (partner) and very little with others. Wanderer males, by contrast, have large territories that overlap with multiple females and remain single. Our data revealed that spatial learning might be more associated with wandering behaviour overall when comparing between tactics. However, we also found that the significance of space use and mating behaviour was contextually dependent, and that spatial learning impacted space use uniquely within each tactic. The relationship with pre-test spatial learning explained the variance for some patterns of space use in the field for residents, and the relationship with post-test spatial learning explained the variance for some patterns of space use in the field for wanderers. Taken together, we conclude that differences in spatial learning ability and how they relate to mating tactics are contextual and best interpreted by examining within- and between-tactic variation. • We tested spatial learning in the lab and alternative mating tactics in the field. • Spatial learning relates to individual variation in space use among mating tactics. • Good spatial learning predicted space use most characteristic of monogamous males. • Good spatial learning related to uncharacteristic space use for nonmonogamous males. • Spatial cognition contextualizes reproductive decision making in prairie voles. [ABSTRACT FROM AUTHOR]

Polyamory is a form of consensual non-monogamy (CNM) based on the belief that people can participate in and build multiple romantic and/or sexual relationships with the consent of all involved. This form of CNM relationship is increasingly visible in societies where monogamy is a prevalent norm. Research in the field of polyamory has yielded many findings regarding the multiple relational benefits of polyamory. However, there is a limited number of studies in the literature focusing specifically on why some people find polyamory more appealing than an exclusive, dyadic partner relationship. Therefore, framed within the historical context in which polyamory emerged and the associated stigmatization, this study presents a model of the psychological motivations for considering/engaging in/remaining in a polyamorous relationship in an era when monogamy and the binary nature of intimate and sexual relationships is being deconstructed. The study is based on a secondary theoretical analysis of recent psychological studies on polyamory, discussed in light of the relevant psychological theories of motivation. The result is an 8-component model of diverse potential polyamory motivations, individually or in aggregate. The motivations were organized into eight domains: fulfilment of needs not met in a monogamous relationship; personal growth and autonomy; identity development and polyamory; expression of political values; exploring minority identities (sexual fluidity and bisexuality); need to belong to a community; desire for sexual diversity; and psychodynamic reasons. This study also shows there may be diversified need of psychotherapeutic approaches for polyamorous individuals. [ABSTRACT FROM AUTHOR]

Parents are faced with multiple, critical tasks, and must prioritize mutually exclusive activities. With biparental care, decisions on prioritization become more complex, as sexes may differ in their prioritization of conflicting behaviours and compensation for changes in their mates' behaviour. Here, I examined the decisions of biparental convict cichlids when they were forced to retrieve displaced young and defend against an intruder. The size and proximity of the potential predator was varied to determine how threat-level influenced prioritization decisions. Males tended to be consistent in their contributions to offspring, regardless of the threat to young. Female parents, however, were much more variable in their care and adjusted their aggression with the size of the intruder and adjusted retrieval in relation to the proximity of the offspring. Sex differences in parental contributions may be due to differences in the parents' ability or willingness to adjust roles and/or differential potential future reproduction. [ABSTRACT FROM AUTHOR]

Size-assortative pairing is common across a wide range of taxa. In many cases, both sexes would benefit from pairing with a mate larger than themselves. As males and females cannot simultaneously be larger than their pair mate, size differences within pairs reflect which sex is able to obtain this benefit. Snapping shrimp can be found in pairs year-round, and both males and females would benefit from pairing with larger individuals. Larger females are more fecund; males, then, are likely to benefit from pairing with larger females primarily in the reproductive season. Larger individuals are more successful competitors and females benefit more from shared burrow defense than males; for females, then, benefits of pairing with larger males are likely to accrue year-round. In this study, we use field data to test whether within-pair size differences in snapping shrimp correspond more to male or female interests, and whether this outcome differs between seasons. We find that size-assortative pairing varies seasonally: although body sizes of paired males and females are highly correlated year-round, the within-pair size difference is greater during the reproductive season than the nonreproductive season. Furthermore, within pairs, females are larger than males during the reproductive season, while pairs are size-matched or male-biased during the nonreproductive season. These changes in within-pair size relationships suggest seasonal differences in which sex has greater control over pair formation, and highlight nonreproductive benefits associated with monogamous pairing. In addition, these results underscore the importance of considering temporal variation in studies of size-assortative pairing. Significance statement: In many taxa, it is advantageous for both males and females to mate with larger individuals. As both sexes cannot simultaneously mate with larger individuals, size relationships within pairs reflect the outcome of this sexual conflict. In snapping shrimp, pairs cooperate in defending their burrows from invading conspecifics, and larger individuals are better competitors; larger females are also more fecund. Thus, males obtain a reproductive advantage from mating with larger females, while for females, mating with larger males provides social (territorial defense) benefits. Here, we find seasonal differences in within-pair size relationships, such that females are larger than males during the reproductive season, but pairs in the nonreproductive season are size-matched or male-biased. These results suggest seasonal variation in the outcome of conflict over body size within pairs, and highlights the need to consider temporal variation in size-assortative pairing. [ABSTRACT FROM AUTHOR]

The genus Bombus (bumble bees) includes approximately 265 species, many of which are in decline in North America and Europe. To estimate colony abundance of bumble bees in natural and agricultural habitats, sibship relationships are often reconstructed from genetic data with the assumption that colonies have 1 monandrous queen. However, some species such as the North American common eastern bumble bee (Bombus impatiens Cresson) can display low levels of polyandry, which may bias estimates of colony abundance based on monandrous sibship reconstructions. To accurately quantify rates of polyandry in wild and commercially mated queens of this species, we empirically estimated mating frequencies using a novel statistical model and genotypes from 730 bees. To genotype individuals, we used a highly polymorphic set of microsatellites on colonies established from 20 wild-caught gynes and 10 commercial colonies. We found multiple fathers in 3 of the wild colonies and 3 of the commercial colonies. This resulted in average effective mating frequencies of 1.075 ± 0.18 and 1.154 ± 0.25 for wild and commercial colonies, respectively. These findings agree with previous reports of low rates of polyandry for B. impatiens. Using a large empirical dataset, we demonstrate that assuming monandry for colony abundance estimation in species that violate this assumption results in an overestimation of the number of colonies. Our results emphasize the importance of studying mating frequencies in social species of conservation concern and economic importance for the accuracy of colony abundance estimation and for understanding their ecology and sociobiology., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)

Polygamy is common in many taxa, particularly birds. Several hypotheses support evolutionary or ecological explanations for the presence of polygamous mating systems, but these may not explain rare occurrences of polygamy in predominantly monogamous systems. We identified 12 cases of polygyny in 3 populations of varying landscape structure (contiguous wildlands. fragmented wildlands, and suburban) across 97 years of collective study on the monogamous Florida Scrub-Jay (Aphelocoma coerulescens). We categorized each case based on social similarities and compared reproduction between monogamous family groups and polygynous males and females. We found no difference in the relative rate of polygyny across the 3 populations. Neither presence of helpers, annual helper sex ratio, or breeder female survival were associated with polygyny occurrence. Reproductive output was similar between polygynous and monogamous males, but significantly lower for polygynous versus monogamous females. Polygyny in Florida Scrub-Jays appears to occur under certain social contexts but is rare even as those contexts are not. Neither sex appears to benefit from polygynous matings but forming a polygynous triad may be better than forgoing breeding. Received H June 2020. Accepted I October 2021. Key words: cooperative breeding, mating systems, monogamy, polygyny, sexual conflict. La poligamia es comiin en machos taxa. particularmente en las aves. Varias hipdtesis dan soportc a explicaciones evolutivas o ccologicas a la presencia dc sistemas de apareo poligamos. si bien estas no dan expliean eventos de poligamia en sistemas preponderantemcnte monogamos. Idcntilicamos 12 casos de poliginia en 3 poblaciones de estructura de paisaje variadas (areas silvestres contiguas. areas silvestres fragmentadas y suburbano) a lo largo de 97 anos de trabajo colectivo en la urraca monogama Aphelocoma coerulescens. Categorizamos cada caso con base en similitudes sociales y comparamos la reproduccion entre grupos familiarcs monogamos, y machos y hembras poliginos. No encontramos diferencias en la tasa relativa dc poliginia entre las 3 poblaciones. Ninguna de estas tres condiciones: presencia de ayudantes, proportion anual dc los sexos de los ayudantes o sobrevivencia de hembras reproductivas. esruvo asociada con dichos eventos de poliginia. El resultado de la reproduction fire similar entre machos poliginos y monogamos. aunque significativamcnte menor para hembras poliginas versus monogamas. La poliginia en estas urracas parece ocurrir bajo ciertos contcxtos sociales pero es raro aiin euando esos contcxtos no lo son. Ninguno de los sexos parece beneficiarse de apareamientos poliginos si bien la formation de triadas poliginas podria ser mejor que evitar reproducirse. Palabras clave: conflicto sexual, monogamia, poliginia, reproduccion cooperativa, sistemas de apareo., Monogamy is hypothesized to occur when conditions favoring polygamy or other mating systems arc absent or costly (Wittenberger and Tilson 1980, Klug 2018). Originally, birds were thought to be predominantly [...]

Since the mid-1980s, our understanding of avian reproductive strategies has shifted as new molecular technologies have revealed how common promiscuity is in many monogamous avian species. However, the prevalence and importance of extra-pair paternity in polygynous species is less well studied. We used microsatellite loci from related icterid species to identify the extra-pair paternity rate in a polygynous population of Bobolinks (Dolichonyx oryzivorus) that bred in the Champlain Valley of Vermont from 2002 to 2018. We assigned paternity for 120 nestlings and found that 42% of nestlings were sired by extra-pair males. These results highlight the importance of extra-pair paternity in the reproductive behavior of Bobolinks that breed in agricultural habitats. Received 29 March 2020. Accepted I October 2021. Key words: leteridae, loci, polygyny, Vermont. Desde mediados de la decada de 1980, nuestro entendimiento de las estrategias reproductivas de aves ha cambiado, mientras nuevas tecnologias moleculares nos revelan que tan comun es la promiscuidad en muchas especies de aves monogamas. Sin embargo, la prevaleneia e importancia de la paternidad extra-pareja especies poliginas esta menos bien estudiada. Usamos loci de microsatelites de ictcridos emparentados para identificar la tasa de paternidad extra-pareja en una pohlacion poligina del tordo arrocero Dolichonyx otyzlvorus que anida en el Champlain Valley de Vermont de 2002-2018. Asignamos la paternidad de 120 polluelos y encontramos que 42% de estos fueron procreados por machos extra-pareja. Estos resultados destacan la importancia de la paternidad extra-pareja en el comportamiento reproductive de los tordos arroceros que anidan en habitats agricolas. Palabras clave: leteridae, loci, poliginia. Vermont., Prior to the widespread use of genetic tools, most avian species were thought to be genetically monogamous (Lack 1968, Gavin and Bollinger 1985, Gowaty 1985). However, mounting evidence has suggested [...]

This study examined the feasibility of monogamy in Canadian adolescents’ romantic relationships by exploring their perceptions of monogamy. Quantitative and qualitative methods were used to gather data: 125 students participated in a survey and 21 students were interviewed. Data was analyzed using a grounded theory approach, and three generalized theories were developed: (1) adolescents highly value monogamy in romantic relationships; (2) although adolescents value monogamy, they believe they are too young to engage in monogamous relationships as it distracts from their priorities such as self-exploration and other life obligations; therefore, adolescents primarily engage in casual romantic relationships as they are not distracting; (3) males and females value monogamy (in general) equally; however, at their current age, females have a stronger preference for casual relationships than males. Since adolescents are more focused on other life priorities than maintaining monogamous relationships, it was concluded that monogamy is not feasible for Canadian adolescents.

The breeding system and mating strategy of a species are at the heart of its behavioral ecology and part of determining its population dynamics. Thus, understanding breeding and mating behavior, and its flexibility, is important for accurate population modeling and successful conservation management. Here, we combine previous work with species‐specific data and phylogenetic context to shine the spotlight on the breeding system of North Island (NI) brown kiwi, Apteryx mantelli, in a conservation context. The NI brown kiwi is of wide interest as a ratite, which are known for their variable breeding biology both within and between species, and its dire need of conservation management. With the aid of data from a long‐term study in a rare, high‐density population, we conclude that, although NI brown kiwi have several features characteristic of monogamous bird species (substantial investment in offspring by both parents, long‐life expectancy, and well‐developed sense of olfaction), it has as many that are consistent with potential for polygamy (uneven quality and distribution of resources, long and asynchronous breeding season, super‐precocial chicks, and non‐monogamous relatives). Consequently, we suggest that (1) the breeding system of NI brown kiwi is more flexible than has been widely recognized, and (2) further study of NI brown kiwi mating behavior would greatly benefit its conservation planning. Specifically, the prevalence of polygamy will directly affect genetic admixture, maintaining of genetic diversity, and distribution of parentage—all crucial factors influencing translocation success and genetic rescue. We argue that the NI brown kiwi study system could contribute to the increased incorporation of behavioral aspects in conservation management, and we provide suggestions for informative studies that would facilitate this. [ABSTRACT FROM AUTHOR]

Monogamy, I've argued, faces a pressing problem: the difficulty of finding a morally relevant difference between its restriction on having additional partners and a restriction on having additional friends. To the extent that we'd find a restriction on having additional friends morally troubling, that puts pressure on us to judge the same about monogamy. This argument, however, has recently come under attack by Kyle York, who defends monogamy on grounds of specialness, practicality, and jealousy. In this paper I'll argue that, pace York, these defenses of monogamy all fail. [ABSTRACT FROM AUTHOR]

Extra-pair paternity is common among socially monogamous birds, but whether females benefit from having extra-pair copulations remains unresolved. In this study, I staged single extra-pair copulations in captive pairs of socially monogamous Japanese quail (Coturnix japonica) and used extra-pair males of a different colour to identify extra-pair fertilizations. This eliminated among-female variation in extra-pair copulations as a source of variation in extra-pair fertilizations and tested whether a single extra-pair copulation would insure against infertility of the social male. Overall, the probability of extra-pair fertilization was 0.46 for the first egg that was fertilized after extra-pair copulation, but this rapidly declined over consecutive eggs in the laying sequence. However, a single extra-pair copulation was effective in ensuring fertilization of the majority of a typical clutch in the few cases where the social male was completely infertile. Hence, my results show that variation in extra-pair paternity can be independent from variation in extra-pair copulation behaviour and that a single, strategically timed, extra-pair copulation can largely insure against social male infertility. Among-female variation in extra-pair fertilizations, and their declining probability over the laying sequence, as typical for many bird species, can thus, in principle, be parsimoniously explained by a uniform female fertility insurance strategy. [ABSTRACT FROM AUTHOR]

Jealousy is the emotional response to a real or imagined threat to an important relationship, and is a common source of distress within romantic and other close interpersonal relationships. In contrast, compersion is the experience of joy in response to a partner experiencing emotional or sexual attraction toward and interactions with another person. In this paper the authors present a contingency analysis of jealous responding and identify ways in which contingencies may be altered to produce a reduction in jealous responding in situations in which this is a targeted goal. Contingencies involved in compersive responding are also propounded, with suggestions as to how compersive responding may be fostered within relationships in which compersion is a goal. [ABSTRACT FROM AUTHOR]

Understanding the neurobiology of social bonding in non-human primates is a critical step in understanding the evolution of monogamy, as well as understanding the neural substrates for emotion and behavior. Coppery titi monkeys (Callicebus cupreus) form strong pair bonds, characterized by selective preference for their pair mate, mate-guarding, physiological and behavioral agitation upon separation, and social buffering. Mate-guarding, or the "maintenance" phase of pair bonding, is relatively under-studied in primates. In the current study, we used functional imaging to examine how male titi monkeys viewing their pair mate in close proximity to a stranger male would change regional cerebral glucose metabolism. We predicted that this situation would challenge the pair bond and induce "jealousy" in the males. Animals were injected with [18F]-fluorodeoxyglucose (FDG), returned to their cage for 30 min of conscious uptake, placed under anesthesia, and then scanned for 1 hour on a microPET P4 scanner. During the FDG uptake, males (n=8) had a view of either their female pair mate next to a stranger male ("jealousy" condition) or a stranger female next to a stranger male (control condition). Blood and cerebrospinal fluid samples were collected and assayed for testosterone, cortisol, oxytocin, and vasopressin. Positron emission tomography (PET) was co-registered with structural magnetic resonance imaging (MRI), and region of interest analysis was carried out. Bayesian multivariate multilevel analyses found that the right lateral septum (Pr(b>0)=93%), left posterior cingulate cortex (Pr(b>0)=99%), and left anterior cingulate (Pr(b>0)=96%) showed higher FDG uptake in the jealousy condition compared to the control condition, while the right medial amygdala (Pr(b>0)=85%) showed lower FDG uptake. Plasma testosterone and cortisol concentrations were higher during the jealousy condition. During the jealousy condition, duration of time spent looking across at the pair mate next to a stranger male was associated with higher plasma cortisol concentrations. The lateral septum has been shown to be involved in mate-guarding and mating-induced aggression in monogamous rodents, while the cingulate cortex has been linked to territoriality. These neural and physiological changes may underpin the emotion of jealousy, which can act in a monogamous species to preserve the long-term integrity of the pair.

Early experience and social context interact to alter the phenotype of complex social behaviors. These early experiences can also result in alterations to cortical organization and connections. Given the ability of the neuropeptide oxytocin (OT) to modulate social and reproductive behavior, OT is likely involved in these cortical processes. However, little is known about the distribution of OT and OT receptors (OTR) within the neocortex. Using autoradiographic and neuroanatomical techniques, we characterized the cortical distribution of OT receptors (OTR) in prairie voles, a socially monogamous rodent species. We found that OTR density was low in the primary sensory areas (including primary somatosensory and auditory regions) but was quite high in association regions (including temporal and parietal association areas, and prelimbic regions). In the primary motor area as well as the temporal and parietal association areas, we observed differences in OTR density across cortical layers. Specifically, cortical layers 2/3 and 5 exhibited greater OTR density than layer 4. Our results point to a role for OT in integrating sensory and motor in the prairie vole brain, providing a complementary mechanism for the modulation of social interactions. Given the ability of early social experience and developmental manipulations of OT to affect the brain and behavior, these results suggest a novel mechanism for how OT may influence cortical organization.

Pair bonding leads to increases in dopamine D1 receptor (D1R) binding in the nucleus accumbens of monogamous prairie voles. In the current study, we hypothesized that there is similar up-regulation of D1R in a monogamous primate, the titi monkey (Callicebus cupreus). Receptor binding of the D1R antagonist [11 C]-SCH23390 was measured in male titi monkeys using PET scans before and after pairing with a female. We found that within-subject analyses of pairing show significant increases in D1R binding in the lateral septum, but not the nucleus accumbens, caudate, putamen, or ventral pallidum. The lateral septum is involved in a number of processes that may contribute to social behavior, including motivation, affect, reward, and reinforcement. This region also plays a role in pair bonding and paternal behavior in voles. Our observations of changes in D1R in the lateral septum, but not the nucleus accumbens, suggest that there may be broadly similar dopaminergic mechanisms underlying pair bonding across mammalian species, but that the specific changes to neural circuitry differ. This study is the first research to demonstrate neuroplasticity of the dopamine system following pair bonding in a non-human primate; however, substantial variability in the response to pairing suggests the utility of further research on the topic.

Social bonds are necessary for many mammals to survive and reproduce successfully. These bonds (i.e. pair-bonds, friendships, filial bonds) are characterized by different periods of development, longevity and strength. Socially monogamous species display certain behaviors not seen in many other mammals, such as adult pair-bonding and male parenting. In our studies of prairie voles (Microtus ochrogaster) and titi monkeys (Callicebus cupreus), we have examined the neurohormonal basis of these bonds. Here, we discuss the evidence from voles that aspects of adolescent and adult social behavior are shaped by early experience, including changes to sensory systems and connections, neuropeptide systems such as oxytocin and vasopressin, and alterations in stress responses. We will compare this with what is known about these processes during development and adulthood in other mammalian species, both monogamous and non-monogamous, and how our current knowledge in voles can be used to understand the development of and variation in social bonds. Humans are endlessly fascinated by the variety of social relationships and family types displayed by animal species, including our own. Social relationships can be characterized by directionality (either uni- or bi-directional), longevity, developmental epoch (infant, juvenile or adult) and strength. Research on the neurobiology of social bonds in animals has focused primarily on 'socially monogamous' species, because of their long-term, strong adult affiliative bonds. In this Review, we attempt to understand how the ability and propensity to form these bonds (or lack thereof), as well as the display of social behaviors more generally, are transmitted both genomically and non-genomically via variation in parenting in monogamous and non-monogamous species.