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。     

Cooperation and conflict among dunnocks, Prunella modularis, in a variable mating system

The mating system of a population of 90 breeding dunnocks (or hedge sparrow, Prunella modularis) included monogamy, polygyny, polyandry and polygynandry. Monogamous males guarded females during their fertile period to prevent neighbouring males from copulating. The most intense guarding occurred where two (unrelated) males shared a territory. Here, the alpha male tried to prevent the beta male from copulating with the female. Beta males were seen to copulate in only half the cases. They were more likely to succeed when the alpha male found it difficult to guard the female closely because her range was large, the vegetation was dense or there were other females breeding synchronously on the same territory. Close guarding and chasing by males reduced the female's feeding rate and was correlated with unhatched eggs in the nest. Females attempted to escape the alpha male's attentions and actively encouraged the beta male to mate. Beta males only helped to feed the young if they copulated with the female. Nestlings fed by two males and a female got more food and weighed more than those fed by just one male and a female. Indirect evidence suggested that when beta males failed to copulate, they destroyed eggs or young chicks. Females laid larger clutches when two males mated with them as opposed to one, thus adapting their clutch size to the amount of parental care they expected. The results of natural removal experiments and matched comparisons of the same female in different mating systems support these conclusions. For females, selection favours cooperative polyandry, whereas for males if favours polygyny; the variable mating system may reflect the different outcomes of this sexual conflict.     

Effects of Single Versus Multiple Mates: Monogamy Results in Increased Fecundity for the Beetle <Emphasis Type="Italic">Phoracantha semipunctata</Emphasis>

Effects of polyandry versus monogamy were assessed for the beetle Phoracantha semipunctata (Coleoptera: Cerambycidae) by comparing measures of female reproductive success, including fecundity, egg viability, time until eclosion, and clutch size. The effect of intermittent presence or absence of a male was also evaluated. Polyandry was detrimental to female reproductive success in comparison to monogamy. Fecundity, egg viability, and clutch size were lower, and time to eclosion were increased for eggs from females with multiple mates compared with monogamous females. Intermittent presence of males had no effect on female reproductive success. Possible explanations for the decreased fecundity experienced by females with multiple mates include sperm competition intensity, costs of male harassment, and exceeding the optimal mating frequency. Females may reduce costs associated with polyandry by spending less time on host logs where mating occurs.     

Costs of large communal clutches for male and female Greater Rheas Rhea americana

The breeding system of the Greater Rhea Rhea americana is almost unique among birds as it combines harem polygyny and sequential polyandry, with communal egg-laying and uniparental male care. In this species, large communal clutches (more than 30 eggs) are rare and have a lower hatching success than smaller clutches. Here we analyse the proximate causes of hatching failures and the costs of large communal clutches (and therefore the costs of extensive polygyny) for males and females. We evaluated if length of the nesting period, egg viability, egg losses during incubation and male parental activity at the nest were affected by clutch size. We also evaluated if chicks hatched from large clutches have a lower survival during the first 2 months after hatching. Large clutches had longer nesting period and lower hatching success, mainly as a result of bacterial contamination of the eggs and increased hatching asynchrony. In addition, large clutches tended to lose more eggs as a result of accidental breakage or predation. Male activity at the nest and chick survival were not related to clutch size. Low hatching success, nest predation risk and energetic costs associated with large clutches penalize females that join large harems and males that accept additional eggs into the nest.     

Punishment of polygyny

We investigated the evolution of monogamy (one male, one female) and polygyny (one male, more than one female). In particular, we studied whether it is possible for a mutant polygynous mating strategy to invade a resident population of monogamous breeders and, alternatively, whether a mutant monogamy can invade resident polygyny. Our population obeys discrete-time Ricker dynamics. The role of males and females in the breeding system is incorporated via the harmonic birth function. The results of the invasability analysis are straightforward. Polygyny is an evolutionarily stable strategy mating system; this holds throughout the examined range of numbers of offspring produced per female. So that the two strategies can coexist, polygyny has to be punished. The coexistence of monogamy and polygyny is achieved by reducing the offspring number for polygyny relative to monogamy. This yields long-term persistence of the strategies for all offspring numbers studied. An alternative punishment is to increase the sensitivity of polygynous breeders to population density. The coexistence is possible only with a limited range of offspring produced. The third way to achieve coexistence of the two mating strategies is to assume that individuals live in a spatially structured population, where dispersal links population subunits to a network. Reducing the dispersal rate of polygynous breeders relative to that of monogamous individuals makes the coexistence feasible. However, for monogamy to persist, the number of offspring produced has to be relatively high.     

Asynchronous arrival pattern, operational sex ratio and occurrence of multiple paternities in a territorial breeding anuran, Rana dalmatina

Understanding why females mate multiply is a major issue in evolutionary ecology. We investigated the consequences of an asynchronous arrival pattern on male competition and multiple paternity in the apparently monoandrous agile frog ( Rana dalmatina ). The largest frogs arrived first and both males and females lost weight significantly during the spawning period. Asynchronous arrival at breeding sites resulted in a male-biased operational sex ratio (OSR). The OSR was more strongly male-biased at the beginning and at the end of the breeding period when the number of satellite males increased. All females mated only once, but multiple paternity within clutches occurred at the beginning and the end of the breeding period. The influence of asynchronous arrival and biased sex ratio suggests that reduced variance or bet-hedging promoting female fitness had only a reduced role in the evolution of polyandry, and polyandry is likely to be associated with male benefits. Polyandry in frogs can be explained either by forced mating as a result of sexual conflict or by clutch piracy. By modifying intrasexual competition, asynchronous arrival and changes in OSR may have a decisive influence upon the evolution of mating systems and favour both polyandry and stable coexistence of alternative mating behaviour.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 86 , 191–200.     

THE CHARACTERISTICS AND OCCURRENCE OF COOPERATIVE POLYANDRY

This paper discusses the relative position of cooperative polyandry among models for the evolution of both polyandry and cooperative breeding. Cooperative polyandry is described as the situation where more than one male and one female breed as a group with males sharing equally in copulations and the care of one set of young. Sequential and simultaneous polyandry are defined to show how they differ from cooperative polyandry. These systems generally are characterized by the care of only one parent for each set of young, a trait which is in sharp contrast to cooperative polyandry. An argument is made that the present models for the evolution of polyandry cannot be expanded to include the cooperatively polyandrous species. Instead, the cooperative traits of cooperative polyandry fit within the array of characteristics of cooperative (communal) breeding. General characteristics of all cooperative species (monogamous, promiscuous and polyandrous) are reviewed and possible reasons for the evolution of equal-status males are discussed. A plea is made for the unification of evolutionary models dealing with mating systems and cooperative systems.     

Mammalian mating systems

Male mammals show a diverse array of mating bonds, including obligate monogamy, unimale and group polygyny and promiscuity. These are associated with a wide variety of different forms of mate guarding, including the defence of feeding and mating territories, the defence of female groups and the defence of individual receptive females. Female mating bonds include long-term monogamy, serial monogamy, polyandry and promiscuity. Both male and female mating behaviour varies widely within species. Variation in male mating behaviour is related to the effect of male assistance in rearing young and to the defensibility of females by males. The latter is, in turn, related to female ranging behaviour and to the size and stability of female groups. Much of the variation in mammalian mating bonds and systems of mate guarding can be attributed to differences in these three variables.     

The effect of mating frequency and mating pattern on female reproductive fitness in cabbage beetle,Colaphellus bowringi

It is generally thought that females can receive more of the material benefits from males by increasing mating frequency and polyandry can lead to greater reproductive success. The cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae), is a highly promiscuous species, in which females or males can readily mate repeatedly with a given partner or multiple partners at a very high frequency. In the present study, the effect of mating frequency (number of matings) and mating pattern (polyandry vs. monogamy) on female reproductive fitness was investigated by measuring fecundity, fertility, and female longevity. The results indicated that increased female mating frequency with the same male did not result in variation in lifetime fecundity, but significantly increased fertility and decreased female longevity. Moreover, five copulations were sufficient to acquire maximal reproductive potential. Female lifetime fecundity also did not differ between polyandrous and monogamous treatments. However, monogamous females exhibited a significant increase in fertility and significant prolongation of longevity compared with polyandrous females, further demonstrating that monogamy is superior to polyandry in this beetle.     

Mating frequency and reproductive success in an income breeding moth,Mnesampela privata

The frequency of mating in insects is often an important determinant of female reproductive output and male sperm competition. In Lepidoptera that provide male nutrients to the female when mating, it is hypothesized that polyandry may be more prevalent. This is thought to be especially so among species described as income breeders; that is, in species who do not derive all their nutrients for reproductive output entirely from the resources obtained during the larval stage. We selected the geometrid moth, Mnesampela privata (Guenée) (Lepidoptera: Geometridae), to examine this hypothesis further. We found this species was best characterized as an income breeder with female weight on emergence positively correlated with total egg load but not with the number of eggs laid. Further, in accord with income breeders, females emerged with a partially developed egg load and lifetime fecundity was positively correlated with the number of oviposition days. However, in the laboratory we found that incidence of repeated matings or polyandry was rare. When moths were paired singly over their lifetime, only 4% of mated females multiple mated. When females were paired with three males concurrently, female mating success increased from 60 to 81% with multiple mating among mated females increasing to just 15%. Dissection of wild caught M. privata found that polyandry levels were also low with a maximum of 16.4% of females collected at any one time being multiple mated. In accord with theory, mating significantly increased the longevity of females, but not of males, suggesting that females acquire essential resources from male ejaculates. Despite this, multiple mated females showed a trend toward decreasing rather than increasing female reproductive output. Spermatophore size, measured on death of the female, was not correlated with male or female forewing length but was negatively correlated with the number of fertile eggs laid and female longevity. Smaller spermatophore width may be related to uptake of more nutrients by the female from a spermatophore. We discuss our findings in relation to income breeding and its relationship to polyandry in Lepidoptera.     

Sexually transmitted diseases in polygynous mating systems: prevalence and impact on reproductive success

Studies of disease in relation to animal mating systems have focused on sexual selection and the evolution of sexual reproduction. Relatively little work has examined other aspects of ecological and evolutionary relationships between host social and sexual behaviour, and dynamics and prevalence of infectious diseases; this is particularly evident with respect to sexually transmitted diseases (STDs). Here, we use a simulation approach to investigate rates of STD spread in host mating systems ranging from permanent monogamy to serial polygyny or polyandry and complete promiscuity. The model assumes that one sex (female) is differentially attracted to the other, such that groups of varying size are formed within which mating and disease transmission occur. The results show that equilibrium disease levels are generally higher in females than males and are a function of variance in male mating success and the likelihood of a female switching groups between mating seasons. Moreover, initial rates of disease spread (determining whether an STD establishes in a population) depend on patterns of host movement between groups, variance in male mating success and host life history (e.g. mortality rates). Male reproductive success can be reduced substantially by a sterilizing STD and this reduction is greater in males that are more 'attractive' to females. In contrast, females that associate with more attractive males have lower absolute fitness than females associating with less attractive males. Thus, the potential for STDs to act as a constraint on directional selection processes leading to polygyny (or polyandry) is likely to depend on the details of mate choice and group dynamics.     

Male nest site fidelity and female serial polyandry in lingcod (Ophiodon elongatus, Hexagrammidae)

Nest site fidelity and serial polyandry were examined in lingcod, Ophiodon elongatus, a teleost fish in which the nest-guarding male parent invests more heavily in parental care than the elusive female parent. Lingcod parental and progeny genotypes were established for fish spawning on a 200 m(2) section of Snake Island reef, British Columbia in two successive years to evaluate male and female mate choice (monogamy or polygamy) and nest site reuse by the same parents (nest site fidelity) and/or different parents (nest site affinity). Thirteen nests (egg masses) guarded by nine males and 14 nests guarded by seven males were observed in 2002 and 2003, respectively. No female laid more than one nest per season or spawned in the study area in both years. In contrast, at least six (86%) and possibly all seven (100%) of the 2003 guardian males had been guardian or auxiliary males in 2002. Both nest site affinity and extreme male nest site fidelity were observed, with at least four males reusing the exact same nest site. Serial polyandry resulting from the high male and low female nest site fidelity is consistent with predictions based on a low female parental investment and high rate of progeny loss to predation and cannibalism. Male polygyny, achieved primarily by cuckoldry within seasons, was enhanced by the lack of female fidelity between seasons. Polygamy in both sexes of nest-tending marine fish may minimize reproductive skew and maximize genetic diversity within populations.     

Saddle-back tamarin (Saguinus fuscicollis) reproductive strategies: Evidence from a thirteen-year study of a marked population

We monitored a population of four to seven groups of individually marked saddle-back tamarins (Saguinus fuscicollis; Callitrichidae) at the Cocha Cashu Biological Station in Peru's Manu National Park every year from 1979 through 1992. In this paper we use data on life histories, group compositions, group formations, and dispersal patterns collected during these 13 years to examine the reproductive strategies of males and females. Group compositions and mating patterns were quite variable in this population, with both monogamy and cooperative polyandry common. In polyandrous groups, two males shared a female's copulations and cooperatively cared for her young. Although most groups contained a single breeding female, we recorded four cases in which secondary females successfully reared young. Most young females appeared to wait in their natal groups for the first opportunity to fill a primary breeding position in their own or a neighboring group. Females that acquired primary breeding positions maintained those positions for a mean of 3 years. No female was observed to transfer between groups a second time. Variation in female lifetime reproductive success was high. Half of the females marked as juveniles never bred; the other half produced an average of 3.5 young. A paucity of female breeding opportunities may explain the high mortality of females between 2.5 and 4.5 years of age and the resulting male-biased adult sex ratio. The majority of groups contained more than one probable male breeder. Polyandrous groups included both related and unrelated males. Behavioral differences between Cocha Cashu tamarins and other studied populations may result from the pressures of living in an environment inhabited by nine other primate species and numerous predators. © 1996 Wiley-Liss, Inc.     

Mating system and demographic constraints on the opportunity for sexual selection

In monogamous systems the fitness difference between males due to competition for mates is limited to one female. This constraint presumably impedes the action of sexual selection relative to polygynous systems. In this paper, we use formal selection theory to show how population size and the adult sex ratio constrain the force of sexual selection and phenotypic evolution under monogamy and polygyny. The force of sexual selection is ultimately constrained by the number of males in a population and the theoretical limit to the rate of male phenotypic evolution is realized if a single male mates with one or many females. These results imply that the force of sexual selection is not strictly constrained by monogamy. The constraint on female phenotypic evolution is typically higher than the constraint on males under polygyny and similar to selection on males in monogamous systems. The sexual asymmetry in the force of selection under polygyny--not necessarily weak sexual selection on males of monogamous systems--may explain the prominence of sexual dimorphism in polygynous systems.     

Tamarin and marmoset mating systems: Unusual flexibility

Recent studies of wild tamarins and marmosets have shown that at least one species exhibits variable mating patterns, including cooperative polyandry, monogamy and, more rarely, polygyny. Polyandry is thought to occur because the high frequency of twinning and the relatively high weights of infants in these species make the rearing of infants unusually difficult. Nonreproductive helpers (older offspring) and polyandrous males may serve as alternative sources of the extra help needed with infant care. The apparent causes of facultative polyandry in saddle-back tamarins are quite different from those of the cooperative polyandry that has been studied in some bird species.     

High frequency of multiple paternity in the largest rookery of Mediterranean loggerhead sea turtles

Mating systems are a central component in the evolution of animal life histories and in conservation genetics. The patterns of male reproductive skew and of paternal shares in batches of offspring, for example, affect genetic effective population size. A prominent characteristic of mating systems of sea turtles seem to be a considerable intra- and interspecific variability in the degree of polyandry. Because of the difficulty of observing the mating behaviour of sea turtles directly in the open sea, genetic paternity analysis is particularly useful for gaining insights into this aspect of their reproductive behaviour. We investigated patterns of multiple paternity in clutches of loggerhead sea turtles in the largest Mediterranean rookery using four highly variable microsatellite loci. Furthermore, we tested for a relationship between the number of fathers detected in clutches and body size of females. More than one father was detected in the clutches of 14 out of 15 females, with two clutches revealing the contribution of at least five males. In more than half the cases, the contributions of different fathers to a clutch did not depart from equality. The number of detected fathers significantly increased with increasing female body size. This relationship indicates that males may prefer to mate with large, and therefore productive, females. Our results suggest that polyandry is likely to increase effective population size compared to a population in which females would mate with only one male; male reproductive contributions being equal.     

Multiple paternity or multiple queens: two routes to greater intracolonial genetic diversity in the eusocial Hymenoptera

Understanding the evolution of multiple mating by females (polyandry) is an important question in behavioural ecology. Most leading explanations for polyandry by social insect queens are based upon a postulated fitness benefit from increased intracolonial genetic diversity, which also arises when colonies are headed by multiple queens (polygyny). An indirect test of the genetic diversity hypotheses is therefore provided by the relationship between polyandry and polygyny across species, which should be negative if the genetic diversity hypotheses are correct. Here, we conduct a powerful comparative investigation of the relationship between polyandry and polygyny for 241 species of eusocial Hymenoptera (ants, bees and wasps). We find a clear and significant negative relationship between polyandry and polygyny after controlling for phylogeny. These results strongly suggest that fitness benefits resulting from increased intracolonial genetic diversity have played an important role in the evolution of polyandry, and possibly polygyny, in social insects.     

Monogamy when there is potential for polygyny: tests of multiple hypotheses in a group-living fish

Monogamy within social groups where there exists a high potentialfor polygyny poses a challenge to our understanding of matingsystem evolution. Specifically, the traditional explanationthat monogamy evolves due to wide female dispersion, affordingmales little opportunity to defend multiple females, cannotapply. Instead, monogamy in groups potentially arises becausefemales compete for breeding resources such as breeding sites,food, and paternal care. We conducted manipulative experimentsto determine whether females compete over limiting resourceswithin groups of the obligate coral-dwelling goby, Paragobiodonxanthosomus (Gobiidae). Breeding females behaved aggressivelytoward individuals of their own sex and evicted subordinatefemales that were large and mature from the group. Experimentalremoval of nest sites caused breeding partners to breed in alternativenest sites, demonstrating that nest site limitation was notthe cause of female competition. Supplemental feeding resultedin an increase in the fecundity of breeding females but no maturationof subordinate females, demonstrating that food-limited femalefecundity was a likely cause of female competition. Finally,supplemental feeding of breeding pairs demonstrated that thedifference in eggs hatched by fed versus unfed males was lessthan the difference in eggs laid by fed versus unfed females,suggesting that paternal care limitation might also drive femalecompetition. These results suggest that competition over foodand possibly paternal care selects for dominant, breeding femalesto suppress the maturation of subordinate females to minimizecompetition. Monogamy in association with group living is thereforelikely to have evolved because female competition prevents malesfrom utilizing the potential for polygyny.     

Colony kin structure and breeding system in the ant genus Plagiolepis

Relatedness is a central parameter in the evolution of sociality, because kin selection theory assumes that individuals involved in altruistic interactions are related. At least three reproductive characteristics are known to profoundly affect colony kin structure in social insects: the number of reproductive queens per colony, the relatedness among breeding queens and queen mating frequency. Both the occurrence of multiple queens (polygyny) and multiple mating (polyandry) decrease within-colony relatedness, while mating among sibs increases relatedness between the workers and the brood they rear. Using DNA microsatellites, we performed a detailed genetic analysis of the colony kin structure and breeding system in three ant species belonging to the genus Plagiolepis: P. schmitzii, P. taurica and P. maura. Our data show that queens of the three species mate multiply: queens of P. maura mate with 1-2 males, queens of P. taurica with 3-11 males and queens of P. schmitzii may have 1-14 different mates. Moreover, colonies are headed by multiple queens: P. taurica and P. maura are facultatively polygynous, while P. schmitzii is obligately polygynous. Despite polyandry and polygyny, relatedness within colonies remains high because all species are characterized by sib-mating, with a fixation index F(it) = 0.25 in P. taurica, 0.24 in P. schmitzii and 0.26 in P. maura, and because the male mates of a queen are on average closely related.     

Why change mates?

In some wading birds (Charadrii) each adult rears a brood alone. The female leaves her first clutch with her first mate before herself rearing a clutch fertilized by a second male, who is already tending its first mate's first clutch. We here develop a simple model to account for the exchange of mates between clutches, and relate it to reported field studies. We suggest that females are attempting to be polygamous, rather than simply bigamous. Provided a female has a chance of obtaining a second, unmated male and that the costs of leaving the first male before remating are not high, matechanging will be favoured over monogamy. The implications of this model to the evolution of the more usual forms of polyandry and of male-like females are discussed.