Social structure and facultative mating systems of hoary marmots (Marmota caligata)

Mate-choice theory predicts different optimal mating systems depending on resource availability and habitat stability. Regions with limited resources are thought to promote monogamy. We tested predictions of monogamy in a social rodent, the hoary marmot (Marmota caligata), at the northern climatic extreme of its distribution. Mating systems, social structure and genetic relationships were investigated within and among neighbouring colonies of marmots within a 4 km(2) valley near Kluane National Park, Yukon, Canada, using 21 microsatellite loci. While both monogamous and polygynous populations of hoary marmots have been observed in the southern reaches of this species' range; northern populations of this species are thought to be predominantly monogamous. Contrary to previous studies, we did not find northern hoary marmot social groups to be predominantly monogamous; rather, the mating system seemed to be facultative, varying between monogamy and polygyny within, as well as among, social groups. These findings reveal that the mating systems within colonies of this species are more flexible than previously thought, potentially reflecting local variation in resource availability.     

田鼠属动物婚配制度的研究范式

从社会组织的生态格局、熟悉性、社会等级和交配近况等择偶行为的影响因子,性二型和雄性射精能力等个体特征,配对关系的神经内分泌机制几方面综述了田鼠动物婚配制度的研究进展,同时从生态学、比较心理学、生理学、神经生物学等方面探讨择偶行类节式的特点。生态学方法,用鼠动物具有完整的婚配制度多样性格局,是婚配制度比较研究的哺乳动物类群。运用比较心理学方法,通过择偶行为实验可直接比较单配制与较研究的理想哺乳动物类     

Female mate preference to maximize paternal care. II. Female competition leads to monogamy

ABSTRACT A two-step game model of female mate preference and paternal care is examined, with a particular focus on the case of two females and two males. In a mating season, females choose their mates, and in the following breeding season males invest in paternal care, knowing the likelihood of their paternity in chicks. If parental ability is the same between individuals of each sex, the evolutionarily stable mating pattern is always monogamy. If females differ in fecundity and males differ in paternal care capacity, monogamy with assortative mating is likely to be evolutionarily stable. If the male cost function increases at a strongly accelerating rate, however, polyandry is evolutionarily stable when the difference of female fecundity is very large, but the game may have no evolutionarily stable state when the difference of female fecundity is small. The care graph (in which females are connected to males giving paternal care to their chicks) is often much simpler than the mating graph (in which females are connected to males they accepted). To be exact, no "loop" should be included in the evolutionarily stable care graph for the general case of n females and m males. This prediction is in accord with the observed prevalence of social monogamy in spite of genetic promiscuity among altricial birds.     

Why do some animals mate with one partner rather than many? A review of causes and consequences of monogamy

Why do some animals mate with one partner rather than many? Here, I investigate factors related to (i) spatial constraints (habitat limitation, mate availability), (ii) time constraints (breeding synchrony, length of breeding season), (iii) need for parental care, and (iv) genetic compatibility, to see what support can be found in different taxa regarding the importance of these factors in explaining the occurrence of monogamy, whether shown by one sex (monogyny or monandry) or by both sexes (mutual monogamy). Focusing on reproductive rather than social monogamy whenever possible, I review the empirical literature for birds, mammals and fishes, with occasional examples from other taxa. Each of these factors can explain mating patterns in some taxa, but not in all. In general, there is mixed support for how well the factors listed above predict monogamy. The factor that shows greatest support across taxa is habitat limitation. By contrast, while a need for parental care might explain monogamy in freshwater fishes and birds, there is clear evidence that this is not the case in marine fishes and mammals. Hence, reproductive monogamy does not appear to have a single overriding explanation, but is more taxon specific. Genetic compatibility is a promising avenue for future work likely to improve our understanding of monogamy and other mating patterns. I also discuss eight important consequences of reproductive monogamy: (i) parentage, (ii) parental care, (iii) eusociality and altruism, (iv) infanticide, (v) effective population size, (vi) mate choice before mating, (vii) sexual selection, and (viii) sexual conflict. Of these, eusociality and infanticide have been subject to debate, briefly summarised herein. A common expectation is that monogamy leads to little sexual conflict and no or little sexual selection. However, as reviewed here, sexual selection can be substantial under mutual monogamy, and both sexes can be subject to such selection. Under long‐term mutual monogamy, mate quality is obviously more important than mate numbers, which in turn affects the need for pre‐mating mate choice. Overall, I conclude that, despite much research on genetic mating patterns, reproductive monogamy is still surprisingly poorly understood and further experimental and comparative work is needed. This review identifies several areas in need of more data and also proposes new hypotheses to test.     

鸟类婚配制度的生态学分类

在Ｅmlen和Ｏring鸟类婚配制度生态学分类系统的基础上,根据近年来鸟类行为生态学研究的成果,对鸟类的婚配制度进行了补充分类,并强调了应以进化稳定策略的观念来认识乌类的婚配制度。补充的鸟类婚配制度生态型包括：合作型一雄一雌制（cooperative monogamy)、临界型一雄一雌制（critical monogamy)、保卫雌性型一雄一雌制（female defense mognogamy)、从领域型一雄多雌制（poly-terri-tory polygyny)和社群繁殖制。合作型一雄一雌制的鸟 类雌雄个体爱力合作才保证繁殖的成功;临界型一悲欢离合一雌制鸟类雌雄个体都有多配倾向,但迫于生态压力必须共同抚育后代才能繁殖成功;保卫雌性型一雄一雌制的鸟 类通过保卫一个雌鸟不被其它雄鸟占有而保证繁殖成功,多领域型一雄多雌制的雄鸟通过占有多个领域而多个雌鸟交配;社群繁殖制的鸟 类由三个以上个体参与工部分参与繁殖,所有个体共同抚育一批后代,现有的鸟类婚配制度可以归为一雄一雌制（monogamy)、一雄多雌繁殖,所有个体共同抚育一批后代。现有的鸟类婚配制度可以归为一雄一雌制(polygyny)、一雌多雄制（polyandry)快速多窝型多配制（rapid-multiple-clutch polygamy)和社群繁殖制（social breeing systen）五大类型。     

Complex mating system and dispersal patterns in a social lizard, Egernia whitii

In contrast to the polygynous mating systems typically displayed by most reptilian taxa, long-term genetic monogamy appears to be widespread within a lineage of group-living Australian scincid lizards, the Egernia group. We have recently shown that White's skink, Egernia whitii, lives in small but temporally stable social aggregations. Here, we examine the mating system, spatial organization, and dispersal patterns of E. whitii using behavioural field studies and data from four microsatellite loci. Parentage analysis of E. whitii litters revealed that its mating system is characterized by both polygyny and monogamy. Polygyny was the predominant mating system but within-season social and genetic monogamy was common (36-45% of breeding pairs). The incidence of between-season monogamy in E. whitii was rare compared to that reported for its congeners. Low levels of multiple paternity (12% of litters) and extra-group paternity (16%) were detected. Social groups are generally comprised of closely related individuals, but breeding pairs were not more closely related compared to other potential mates. Spatial autocorrelation analyses revealed significant positive local genetic structure over 50 m, which was consistent for all age-sex classes. There was no clear and consistent evidence for sex-biased dispersal, with assignment tests (mean assignment index) and relatedness analyses suggesting female-biased dispersal, but spatial autocorrelation analyses indicating a trend for male-biased dispersal. We discuss the implication of our results in regard to the factors promoting the evolution of monogamy within the Egernia group.     

Mate Familiarity Affects Pairing Behaviour in a Long‐Term Monogamous Lizard: Evidence from Detailed Bio‐Logging and a 31‐Year Field Study

Long‐term monogamy is most prevalent in birds but is also found in lizards. We combined a 31‐year field study of the long‐lived, monogamous Australian sleepy lizard, Tiliqua rugosa, with continuous behavioural observations through GPS data logging, in 1 yr, to investigate the duration of pair bonds, rates of partner change and whether either the reproductive performance hypothesis or the mate familiarity hypothesis could explain this remarkable long‐term monogamy. The reproductive performance hypothesis predicts higher reproductive success in more experienced parents, whereas the mate familiarity hypothesis suggests that effects of partner familiarity select for partner retention and long‐term monogamy. Rates of partner change were below 34% over a 5‐yr period and most sleepy lizards formed long‐term pair bonds: 31 partnerships lasted for more than 15 yr, 110 for more than 10 yr, and the recorded maximum was 27 yr (ongoing). In the year when we conducted detailed observations, familiar pairs mated significantly earlier than unfamiliar pairs. Previous pairing experience (total number of years paired with previous partners) had no significant effect. Early mating often equates to higher reproductive success, and we infer that is the case in sleepy lizards. Early mating of familiar pairs was not due to better body condition. We propose two suggestions about the proximate mechanisms that may allow familiar pair partners to mate earlier than unfamiliar partners. First, they may have improved coordination of their reproductive sexual cycles to reach receptivity earlier and thereby maximise fertilisation success. Second, they may forage more efficiently, benefiting from effective information transfer and/or cooperative predator detection. Those ideas need empirical testing in the future. Regardless of the mechanism, our observations of sleepy lizard pairing behaviour support the mate familiarity hypothesis, but not the reproductive performance hypothesis, as an explanation for its long‐term monogamous mating system.     

田鼠婚配制度的神经内分泌基础

作为繁殖行为的一种表现形式,婚配制度是通过长期进化而形成的,具有种属特异性及可遗传性。因此,不同的婚配制度具有不同的生理基础。这种生理基础由3级结构组成：神经直接启动并维持繁殖行为;激素或通过诱导特异神经通路的发育或直接激活神经传导影响繁殖行为;基因则可能是通过调节激素的代谢和作用方式来控制与繁殖行为相关的神经系统。田鼠脑中涉及婚配制度的区域集中在视前区中部（MPOA）,腹被盖区（VTA）,膈部及纹状体端部。起作用的激素主要是催产素（OT）和后叶加压素（AVP）。导致田鼠形成不同婚配制度的最终原因可能是这两种激素受体基因上的差异。受体基因调控区的启动子序列存在变异,导致脑中受体基因在表达区域上的差异,进而使激素激活不同的神经通路,产生不同的繁殖行为及婚配制度。     

God Is Nothing but Talk: Modernity, Language, and Prayer in a Papua New Guinea Society

This article brings together theories of local modernity and of linguistic ideology to analyze the way the Urapmin of Papua New Guinea have encountered modern linguistic ideology through their Christianization. Against the prevailing anthropological focus on the indigenization of modernity, this article argues the importance of attending to cases in which people grasp the content of modernity on its own terms. Studying this kind of local modernity allows us to model an important kind of contemporary cultural change and discover neglected aspects of modernity as refracted through the experiences of people new to it. Here, an analysis of the Urapmin encounter with modern linguistic ideology reveals that ideology's rootedness in a model that ties meaning to intention and truthfulness and favors the speaker over the listener in the construction of meaning. It is suggested that an awareness of the biases of this ideology can open up new topics in linguistic anthropology. [ modernity, linguistic ideology, religion, Christianity, Melanesia ]     

On switches and knobs, microsatellites and monogamy

Comparative studies in voles have suggested that a polymorphic microsatellite upstream of the Avpr1a locus contributes to the evolution of monogamy. A recent study challenged this hypothesis by reporting that there is no relationship between microsatellite structure and monogamy in 21 vole species. Although the study demonstrates that the microsatellite is not a universal genetic switch that determines mating strategy, the findings do not preclude a substantial role for Avpr1a in regulating social behaviors associated with monogamy.     

The evolution of avian mating systems: a phylogenetic analysis of male and female polygamy and length of pair bond

A phylogenetic analysis of the evolution of mating systems in birds was made, based on the phylogeny of Sibley and Ahlquist. Both the mating behaviour and the social behaviour of species were classified for males and females, according to (1) the frequency of mated individuals in a species having several mates in a breeding season compared to those having one mate (the mating pattern), and (2) whether there is a bond between males and females, and in case of there being a bond, to the length of the bond. Non-passerines are extensively analysed, whereas we only give a survey of the situation in passerines. In non-passerine birds, the number of inferred transitions from monogamy to polygamy are 15 for females and 16–23 for males. Almost all transitions between different states of mating pattern are to higher states of polygamy. Our analyses also show a concentration of transitions to polygamy and short bonds, respectively, in the two monophyletic groups of Struthionidae-Anatidae and Pteroclidae-Laridae.     

Re-Evaluating Primate Monogamy

Researchers propose hypotheses for the occurrence of monogamy as a social system in primates based on the assumption that there are a group of primates, including humans, which live exclusively in "nuclear families" and share a similar set of social behaviors. Examining the primates purported to be "monogamous" reveals that they cover a wide range of grouping types, mating patterns, taxonomic groups, and evolutionary grades. While there are a few primate species that do live in small, two-adult groups and share a similar set of social behaviors, the vast majority of the supposed "monogamous" primates, including humans, do not. [monogamy, social systems, evolution, variability in social organization]     

No evidence of immediate fitness benefits of within-season divorce in monogamous birds

Individuals of socially monogamous species can correct for suboptimal partnerships via two secondary mating strategies: divorce and extra-pair mating, with the former potentially providing both genetic and social benefits. Divorcing between breeding seasons has been shown to be generally adaptive behaviour across monogamous birds. Interestingly, some pairs also divorce during the breeding season, when constraints on finding a new partner are stronger. Despite being important for a comprehensive understanding of the evolution of social monogamy, whether within-season divorce is adaptive and how it relates to extra-pair mating remains unknown. Here, we meta-analysed 90 effect sizes on within-season divorce and breeding success, extracted from 31 studies on 24 species. We found no evidence that within-season divorce is adaptive for breeding success. However, the large heterogeneity of effect sizes and strong phylogenetic signal suggest social and environmental factors—which have rarely been considered in empirical studies—may play an important role in explaining variation among populations and species. Furthermore, we found no evidence that within-season divorce and extra-pair mating are complementary strategies. We discuss our findings within the current evidence of the adaptiveness of secondary mating strategies and their interplay that ultimately shapes the evolution of social monogamy.     

Testing for local adaptation in adult male and female fitness among populations evolved under different mate competition regimes

Mating/fertilization success and fecundity are influenced by sexual interactions among individuals, the nature and frequency of which can vary among different environments. The extent of local adaptation for such adult fitness components is poorly understood. We allowed 63 populations of Drosophila melanogaster to independently evolve in one of three mating environments that alter sexual interactions: one involved enforced monogamy, while the other two permitted polygamy in either structurally simple standard fly vials or in larger “cages” with added complexity. Adult male and female reproductive fitness were measured after 16 and 28 generations, respectively, via full reciprocal transplants. In males, reciprocal local adaptation was observed between the monogamy and simple polygamy treatments, consistent with the evolution of reproductively competitive males under polygamy that perform poorly under monogamy because they harm their only mate. However, males evolved in the complex polygamy treatment performed similarly or better than all other males in all mating environments, consistent with previous results showing higher genetic quality in this treatment. Differences in female fitness were more muted, suggesting selection on females was less divergent across the mating treatments and echoing a common pattern of greater phenotypic and expression divergence in males than females.     

Correlates of genetic monogamy in socially monogamous mammals: insights from Azara's owl monkeys

Understanding the evolution of mating systems, a central topic in evolutionary biology for more than 50 years, requires examining the genetic consequences of mating and the relationships between social systems and mating systems. Among pair-living mammals, where genetic monogamy is extremely rare, the extent of extra-group paternity rates has been associated with male participation in infant care, strength of the pair bond and length of the breeding season. This study evaluated the relationship between two of those factors and the genetic mating system of socially monogamous mammals, testing predictions that male care and strength of pair bond would be negatively correlated with rates of extra-pair paternity (EPP). Autosomal microsatellite analyses provide evidence for genetic monogamy in a pair-living primate with bi-parental care, the Azara''s owl monkey (Aotus azarae). A phylogenetically corrected generalized least square analysis was used to relate male care and strength of the pair bond to their genetic mating system (i.e. proportions of EPP) in 15 socially monogamous mammalian species. The intensity of male care was correlated with EPP rates in mammals, while strength of pair bond failed to reach statistical significance. Our analyses show that, once social monogamy has evolved, paternal care, and potentially also close bonds, may facilitate the evolution of genetic monogamy.     

Rapid decreases in relative testes mass among monogamous birds but not in other vertebrates

Larger testes produce more sperm and therefore improve reproductive success in the face of sperm competition. Adaptation to social mating systems with relatively high and low sperm competition are therefore likely to have driven changes in relative testes size in opposing directions. Here, we combine the largest vertebrate testes mass dataset ever collected with phylogenetic approaches for measuring rates of morphological evolution to provide the first quantitative evidence for how relative testes mass has changed over time. We detect explosive radiations of testes mass diversity distributed throughout the vertebrate tree of life: bursts of rapid change have been frequent during vertebrate evolutionary history. In socially monogamous birds, there have been repeated rapid reductions in relative testes mass. We see no such pattern in other monogamous vertebrates; the prevalence of monogamy in birds may have increased opportunities for investment in alternative behaviours and physiologies allowing reduced investment in expensive testes.     

Schistosome monogamy: who,how, and why?

Schistosomes represent a unique animal model for comparative analyses of monogamy. Indeed, schistosomes are classified at the lowest taxonomical level of monogamous species and lack complex social interactions, which could alter our understanding of their unusual mating system. Elements discussed here include the fact that monogamy in schistosomes could be an ancestral state between hermaphroditism and polygyny or polygynandry and the occurrence of mate changes. In addition, hypotheses are proposed to explain monogamy in schistosomes (e.g. female dispersion, the need for paternal care, oviposition site limitation or aggressiveness, and mate guarding). We also propose future experimental and analytical approaches to improve our understanding of the schistosomes' mating system.     

Monogamy and brood parasitism: an unlikely pair

Intensive observation of a population of brood parasitic brown-headed cowbirds (Molothrus ater), including 114 marked birds, demonstrated that monogamy is the prevalent mating system. Analysis of 1280 consort events and 73 copulations showed that nearly all copulations were between a female and the male most often seen with her, even though females had ample opportunities to mate with other males. Although monogamy prevails, some pair bonds do not endure throughout the breeding season. They are more unstable during the early season when resident cowbirds are establishing their social interrelations. This study provides strong evidence that the cowbird's mating system varies geographically, as the only previous study based on observed copulations demonstrated promiscuity. Current hypotheses for the evolution of avian mating systems, when considered in light of the field data presently available, do not fully explain the adaptive significance of monogamy in a parasitic bird.     

The evolution of avian parental care

A stage model traces key behavioural tactics and life-history traits that are involved in the transition from promiscuity with no parental care, the mating system that typifies reptiles, to that typical of most birds, social monogamy with biparental care. In stage I, females assumed increasing parental investment in precocial young, female choice of mates increased, female-biased mating dispersal evolved and population sex ratios became male biased. In stage II, consortships between mating partners allowed males to attract rare social mates, provided a mechanism for paternity assessment and increased female ability to assess mate quality. In stage III, relative female scarcity enabled females to demand parental investment contributions from males having some paternity certainty. This innovation was facilitated by the nature of avian parental care; i.e. most care-giving activities can be adopted in small units. Moreover, the initial cost of care giving to males was small compared with its benefit to females. Males, however, tended to decline to assume non-partitionable, risky, or relatively costly parental activities. In stage IV, altriciality coevolved with increasing biparental care, resulting in social monogamy. Approaches for testing behavioural hypotheses are suggested.     

Ultimate Causation of Aggressive and Forced Copulation in Birds: Female Resistance, the CODE Hypothesis, and Social Monogamy

SYNOPSIS. Except in ducks and geese (Anseriforms), aggressiveor forced copulation in birds is rare. The rarity of forcedcopulation in birds theoretically is dueto morphological andphysiological mechanisms of female resistance that place fertilizationmost often under female control. Traits theoretically associatedwith resistance by females include: digestive epithelium liningthe section of the cloaca receiving sperm and powerful doacalmusculature used to eject contents, including waste materialand sperm. These traits suggest that the Immediate FertilizationEnhancement Hypothesis may be an inadequate ultimate explanationfor forced copulation when it occurs. Ideas in Heinroth (1911)and Brownmiller (1975) suggested an alternative, the CODE Hypothesis,which says that aggressive copulation creates a dangerous environmentfor females. This, in turn, fosters male mating advantage viasocial monogamy, because selection sometimes favors femaleswho trade sexual and social access for protection from maleaggression. Thus, theoretically, "trades" of protection forcopulation favor the evolution of social monogamy even in specieswith little or no paternal care. Individual males may accrueselective advantages through direct benefits, kin-selected benefits,or reciprocal altruism. The CODE hypothesis for social monogamypredicts variation in extrapair paternity from preferred mates,variation in male reproductive success, and variation amongfemales' post-insemination resistance mechanisms as functionsof variation among females' vulnerabilities (ecological andintrinsic) to aggressive copulation. Observers will base intraspecifictests on variation among females in their vulnerabilities tomale aggression against them.