No brood parasitism by the Great Spotted Cuckoo Clamator glandarius on the Azure-winged Magpie Cyanopica cyanus

Capsule No case of parasitic interaction was found after 12 years of intensive monitoring of a marked population in Spain where both species are sympatric.

Aims To evaluate whether the Azure-winged Magpie is parasitized, and suggest possible causes that affect its relationship with the Great Spotted Cuckoo.

Methods Data from a long-term field study of marked individuals in a population of Azure-winged Magpie in Spain, were collected from about 60 nests per year over 12 years.

Results Although common in the area, no eggs or young of the Great Spotted Cuckoo were found in an Azure-winged Magpie nest.

Conclusion The Great Spotted Cuckoo does not appear to parasitize the Azure-winged Magpie, and we suggest that elevated predation rates on nests may be an important, overlooked factor potentially affecting the choice of host species by this brood parasite.     

Female choice and extra-pair paternity in a traditional human population

Seeking out extra-pair paternity (EPP) is a viable reproductive strategy for females in many pair-bonded species. Across human societies, women commonly engage in extra-marital affairs, suggesting this strategy may also be an important part of women's reproductive decision-making. Here, I show that among the Himba 17 per cent of all recorded marital births are attributed by women to EPP, and EPP is associated with significant increases in women's reproductive success. In contrast, there are no cases of EPP among children born into 'love match' marriages. This rate of EPP is higher than has been recorded in any other small-scale society. These results illustrate the importance of seeking EPP as a mechanism of female choice in humans, while simultaneously showing it to be highly variable and context-dependent.     

No evidence for extra-pair paternity in the western gull

The genetic mating system of western gulls Larus occidentalis breeding on Southeast Farallon Island, California, was determined using multilocus DNA fingerprints of 33 chicks from 22 broods. No extra-pair paternity (EPP) was found, despite extra-pair copulations (EPCs) occurring. This suggests that paternity guards are effective, and that females gain few genetic benefits from EPCs. The EPP in western gulls concurs with that of other seabirds, reinforcing the idea that seabirds generally have a monogamous genetic mating system.     

Low frequency of extra-pair paternity in Common Gulls (Larus canus) as revealed by DNA fingerprinting

Summary During the last decade, the mating systems of many bird species have been analysed using molecular genetic methods. Most of these studies were performed on Passeriformes while Non-Passeriformes were rarely investigated. To fill this gap, we analysed blood samples of 24 Common Gull (Larus canus) families from two Polish colonies using DNA fingerprinting. A total of 55 of 56 chicks was unequivocally assigned to their genetic parents. Only two of these chicks (3.6%) from two different broods resulted from extra-pair copulations, the other 53 could be attributed to the putative parents; i.e., intraspecific brood parasitism was not observed. With respect to the number of breeding pairs investigated, the frequency of extra-pair paternity amounted to 8.3%. Thus, extra-pair paternity is relatively infrequent compared to other bird species. This result is surprising because the percentage of observed extra-pair copulations (i.e., mainly forced copulations in Common Gulls) in relation to the absolute number of copulations was 15.7% in the colonies studied. A possible reason for the disproportionate number of forced copulations and the lower percentage of resulting extra-pair young may include different mechanisms for paternity control by the pair males and/or by females.

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Niedriger Anteil von Vaterschaften außerhalb des Paarbundes bei Sturmmöwen (Larus canus)

Zusammenfassung In den letzten 10 Jahren wurde das Paarungssystem vieler Vogelarten auch mit Hilfe molekulargenetischer Methoden näher untersucht. Dabei standen vor allem verschiedene Singvogelarten im Vordergrund, während Nicht-Singvogelarten kaum berücksichtigt wurden. Die vorliegende Untersuchung an Sturmmöwen (Larus canus) soll helfen diese Lücke zu schließen. Hierzu wurden die Blutproben von 24 Sturmmöwenfamilien zweier polnischer Kolonien mit Hilfe des genetischen Fingerabdruckverfahrens untersucht. Bei 55 der 56 untersuchten Küken konnten eindeutige Aussagen zur Elternschaft gemacht werden. Nur zwei Küken (3,6%) aus zwei unterschiedlichen Bruten gingen auf Kopulationen außerhalb des Paarbundes zurück, die restlichen 53 stammten von den sozialen Eltern ab, d. h. Fälle von innerartlichem Brutparasitismus konnten nicht nachgewiesen werden. In bezug auf den prozentualen Anteil an Brutpaaren, deren Bruten Jungtiere enthielten, die das Resultat von Kopulationen außerhalb des Paarbundes waren, ergab sich ein Wert von 8,3%. Dieser Wert ist im Vergleich mit anderen Vogelarten sehr niedrig. Der geringe Anteil an Vaterschaften außerhalb des Paarbundes verwundert, da der Anteil von Kopulationen außerhalb des Paarbundes, die von den Männchen bei Sturmmöwen meist gewaltsam erzwungen werden, im Vergleich zur Gesamtzahl beobachteter Kopulationen in den untersuchten Kolonien 15,7% betrug und damit deutlich höher lag, als dies auf der Basis der Ergebnisse der DNA-Fingerprinting Untersuchungen zu erwarten gewesen wäre. Mögliche Gründe für die Diskrepanz zwischen dem Anteil der erzwungenen Kopulationen außerhalb des Paarbundes und dem Anteil der resultierenden Küken sind verschiedene Mechanismen der Vaterschaftskontrolle durch die Paarmännchen und/oder durch die Weibchen.

     

Covariance of paternity and sex with laying order explains male bias in extra-pair offspring in a wild bird population

It has been hypothesized that parents increase their fitness by biasing the sex ratio of extra-pair offspring (EPO) towards males. Here, we report a male bias among EPO in a wild population of blue tits (Cyanistes caeruleus). This resulted from a decline in both the proportion of males and EPO over the laying order of eggs in the clutch. However, previous studies suggest that, unlike the decline in EPO with laying order, the relationship between offspring sex ratio and laying order is not consistent between years and populations in this species. Hence, we caution against treating the decline in proportion of males with laying order, and the resulting male bias among EPO, as support for the above hypothesis. Variable patterns of offspring sex and paternity over the laying order may explain inconsistent associations between offspring sex and paternity, between and within species.     

Effects of extra-pair and within-pair reproductive success on the opportunity for selection in birds

The number of mates, their fecundity, and the number of extra-pairfertilizations can all affect male reproductive success in biparentalspecies. Extra-pair mating in birds has been of particular interest,because it could generate strong levels of sexual selectioneven when a species is socially monogamous. We examined howextra-pair fertilizations affect the opportunity for selectionin the sexually dimorphic common yellowthroat (Geothlypis trichas)and the sexually monomorphic house wren (Troglodytes aedon).We were able to identify sires for at least 95% of all nestlings,and, thus, we were able to make a nearly complete accountingof male reproductive success. Although extra-pair fertilizationswere common in yellowthroats (26% of young) it contributed little(21%) to the total variance in male reproductive success. Mostof the variance in reproductive success (58%) was attributableto the male's within-pair success, which was influenced primarilyby the number of young produced by each mate and the proportionof within-pair young sired. Despite a moderate level of extra-pairfertilizations (10% of young) in house wrens, almost all ofthe variance in male reproductive success (97%) was attributableto within-pair success, particularly the number of social mates.Although extra-pair fertilizations generally increase the variancein male reproductive success, within-pair reproductive successmay be the major source of variation in male reproductive success.Thus, sexual dimorphism in monogamous birds may be influencedmore by the number of mates and their fecundity than by extra-pairmatings.     

How female reed buntings benefit from extra-pair mating behaviour: testing hypotheses through patterns of paternity in sequential broods

Extra-pair paternity is an important aspect of reproductive strategies in many species of birds. Given that in most species females control whether fertilization occurs, they are expected to benefit in some way from the extra-pair matings. In this study we use patterns of extra-pair paternity (EPP) in broods of individual reed buntings (Emberiza schoeniclus), both within and between seasons, to test four hypothesized female benefits: (1) assessing potential future partners and seeking (2) genetic diversity (3) good genes, or (4) compatible genes. Reed buntings are socially monogamous, multibrooded passerines with extremely high levels of extra-pair paternity. We studied a population of reed buntings in the Netherlands in 2002 and 2003; 51% of offspring in 74% of nests were extra-pair. We showed that patterns of EPP did not support the first and second hypotheses, since females did not form a pair with previous extra-pair partners, EPP was not evenly distributed among broods and more broods than expected were sired by a single male. Furthermore, there was no relation between a male's within- and extra-pair fertilization success, no consistency in EPP between breeding attempts, no effect of parental relatedness on EPP and several cases of reciprocal paternity. These patterns do not support the good genes hypothesis and are most consistent with the genetic compatibility hypothesis. However, our previous finding that older males are more successful in gaining EPP, suggests some effect of good genes. These hypotheses need not be mutually exclusive, as females may select compatible males above a certain quality threshold (e.g. old males).     

Sex-specific differential survival of extra-pair and within-pair offspring in song sparrows, Melospiza melodia

It is widely hypothesized that the evolution of female extra-pair reproduction in socially monogamous species reflects indirect genetic benefits to females. However, a critical prediction of this hypothesis, that extra-pair young (EPY) are fitter than within-pair young (WPY), has rarely been rigorously tested. We used 18 years of data from free-living song sparrows, Melospiza melodia, to test whether survival through major life-history stages differed between EPY and WPY maternal half-siblings. On average, survival of hatched chicks to independence from parental care and recruitment, and their total lifespan, did not differ significantly between EPY and WPY. However, EPY consistently tended to be less likely to survive, and recruited EPY survived for significantly fewer years than recruited WPY. Furthermore, the survival difference between EPY and WPY was sex-specific; female EPY were less likely to survive to independence and recruitment and lived fewer years than female WPY, whereas male EPY were similarly or slightly more likely to survive and to live more years than male WPY. These data indicate that extra-pair paternity may impose an indirect cost on females via their female offspring and that sex-specific genetic, environmental or maternal effects may shape extra-pair reproduction.     

Lifespan, lifetime reproductive performance and paternity loss of within-pair and extra-pair offspring in the coal tit Periparus ater

The hypothesis that females of socially monogamous species obtain indirect benefits (good or compatible genes) from extra-pair mating behaviour has received enormous attention but much less generally accepted support. Here we ask whether selection for adult survival and fecundity or sexual selection contribute to indirect selection of the extra-pair mating behaviour in socially monogamous coal tits (Periparus ater). We tracked locally recruited individuals with known paternity status through their lives predicting that the extra-pair offspring (EPO) would outperform the within-pair offspring (WPO). No differences between the WPO and EPO recruits were detected in lifespan or age of first reproduction. However, the male WPO had a higher lifetime number of broods and higher lifetime number of social offspring compared with male EPO recruits, while no such differences were evident for female recruits. Male EPO recruits did not compensate for their lower social reproductive success by higher fertilization success within their social pair bonds. Thus, our results do not support the idea that enhanced adult survival, fecundity or within-pair fertilization success are manifestations of the genetic benefits of extra-pair matings. But we emphasize that a crucial fitness component, the extra-pair fertilization success of male recruits, has yet     

Tests of spatial and temporal factors influencing extra-pair paternity in red-winged blackbirds

Extra-pair paternity (EPP) is a widespread and highly variable reproductive phenomenon in birds. We tested the effects of habitat, spatial factors, and timing of breeding on the occurrence of EPP in red-winged blackbirds (Agelaius phoeniceus). We used PCR-amplified microsatellites to assess the paternity of 1479 nestlings from 537 broods on 235 territories over four breeding seasons. Over 4 years, 40% of nestlings were extra-pair. At least 27% of actual sires were non-neighbours, suggesting that males or females interacted over longer distances than in other populations of red-winged blackbirds. The level of EPP was significantly clumped within broods and males but not within females across broods. EPP was negatively related to the area of a male's territory. The spatial proximity of a female's nest to the territory boundary had no effect on total EPP, but tended to increase the probability of an EPP by a nearby male. We found no influence on EPP of the type of habitat on the territory or the level of nesting activity nearby. The time in the season when a nest was started and the synchrony of breeding also had no significant effect on the level of EPP. The age of the male, the age of his neighbours, and the interaction between the two had no effect on total EPP. However, older males were less likely to have an offspring sired by a neighbour on their territory. Males with older neighbours were also less likely to have offspring sired by a neighbour, particularly if they were new territory owners. The high variability in who gained and lost paternity, and the limited impact of spatial and temporal factors influencing it, have some interesting implications for theories seeking to explain mating patterns.     

Immune response of nestling warblers varies with extra-pair paternity and temperature

Extra-pair mating is widespread in birds, but its adaptive function remains unclear. It is often suggested that females obtain superior genes for their offspring as a consequence of extra-pair mating, but the evidence is limited. In this study, we examined the hypothesis that extra-pair mating provides females with offspring that have superior immune responses. We found that the T-cell-mediated immune response of extra-pair young was stronger than that of within-pair young in common yellowthroats (Geothlypis trichas). This paternity effect occurred when we compared all nestlings in the population, as well as in comparisons of both paternal and maternal half-siblings. Paternal half-siblings had a stronger immune response when they were produced with extra-pair females than with the male's social mate, which suggests that the greater immune response of extra-pair young was caused by nonadditive (compatible) genetic effects. However, these patterns were only significant in the colder of 2 years. Immune response was related positively to air temperature and nestlings had a stronger immune response in the warmer year. We suggest that such environmental variation could obscure the genetic benefits of extra-pair mating.     

Promiscuity, paternity and personality in the great tit

Understanding causes of variation in promiscuity within populations remain a major challenge. While most studies have focused on quantifying fitness costs and benefits of promiscuous behaviour, an alternative possibility--that variation in promiscuity within populations is maintained because of linkage with other traits-has received little attention. Here, we examine whether promiscuity in male and female great tits (Parus major)--quantified as extra-pair paternity (EPP) within and between nests--is associated with variation in a well-documented personality trait: exploration behaviour in a novel environment. Exploration behaviour has been shown to correlate with activity levels, risk-taking and boldness, and these are behaviours that may plausibly influence EPP. Exploration behaviour correlated positively with paternity gained outside the social pair among males in our population, but there was also a negative correlation with paternity in the social nest. Hence, while variation in male personality predicted the relative importance of paternity gain within and outside the pair bond, total paternity gained was unrelated to exploration behaviour. We found evidence that males paired with bold females were more likely to sire extra-pair young. Our data thus demonstrate a link between personality and promiscuity, with no net effects on reproductive success, suggesting personality-dependent mating tactics, in contrast with traditional adaptive explanations for promiscuity.     

灰喜鹊的繁殖生态和巢位选择Ⅰ.繁殖生态

灰喜鹊的繁殖生态和巢位选择Ⅰ．繁殖生态汝少国侯文礼（青岛海洋大学海洋生命学院,２６６００３）（东北师范大学环境科学系,长春１３００２４）刘云李多元（青岛海洋大学海洋生命学院,２６６００３）（东北师范大学环境科学系,长春１３００２４）ＴｈｅＢｒｅｅｄｉ...     

Variation in the extra-pair mating systems of Acadian Flycatchers and Wood Thrushes in forest fragments in southern Ontario

ABSTRACT.   The application of molecular tools to studies of avian mating systems has revealed that most songbird species engage in extra-pair matings. However, little is known about the possible effects of habitat fragmentation on extra-pair mating systems. During the breeding seasons of 2002 and 2003, we quantified the frequency of extra-pair matings in Acadian Flycatchers ( Empidonax virescens ) and Wood Thrushes ( Hylocichla mustelina ) nesting in forest fragments in southern Ontario. Acadian Flycatchers are at the limit of their northern range in southern Ontario and occurred at low densities (0.005–0.015 males/ha). Across forest fragments, 14% of young Acadian Flycatchers were the result of extra-pair fertilizations. In contrast, Wood Thrushes were common in forest fragments, with breeding densities ranging from 0.37 to 1 males/ha. Extra-pair mating was common among Wood Thrushes, with 40% of young the result of extra-pair matings. Compared to populations studied in less fragmented habitats in Pennsylvania, rates of extra-pair paternity in Ontario were lower for Acadian Flycatchers and higher for Wood Thrushes. Our results demonstrate that rates of extra-pair mating can vary across landscapes. However, the extra-pair mating systems of Acadian Flycatchers and Wood Thrushes appear to respond differently to fragmentation. We suggest that low breeding densities on fragments may be mediating the low rates of extra-pair mating observed in Acadian Flycatchers in southern Ontario, whereas changes to the behavioral tactics of male and female Wood Thrushes in southern Ontario may explain the high levels of extra-pair mating.     

Low frequency of extra-pair paternity in two colonies of the socially monogamous short-tailed shearwater Puffinus tenuirostris

The short-tailed shearwater is a colonially nesting, socially monogamous seabird. Little is known about mate fidelity and breeding behaviour in this species because breeding birds are nocturnal on land and spend much of their time within subterranean nesting burrows. Colonial breeding and extended sperm storage create opportunities for extra-pair copulations which may form a significant component of the mating strategy in this species. Multilocus DNA fingerprinting was used to examine the genetic relationship between nestlings and the male and female nest attendants in 83 burrows from two distinct breeding colonies. Genetic analyses identified nine nestlings, approximately equally distributed between the two colonies, that were not related to the attendant pair male in those burrows, implying extra-pair paternity through extra-pair copulations. These results are used retrospectively to discuss the characteristics of extra-pair copulations and extra-pair fertilizations and the implications for estimates of life-time reproductive success in the short-tailed shearwater.     

Female house wrens (Troglodytes aedon) increase the size, but not immunocompetence, of their offspring through extra-pair mating

House wrens are typically socially monogamous, but frequently engage in extra-pair matings leading to multisired broods. Because females do not appear to acquire direct material benefits from their extra-pair mates, we tested the hypothesis that female house wrens derive indirect genetic benefits, such as enhanced immunocompetence (cutaneous immune activity, humoral immunity, and plasma bactericidal activity) and condition (size and haematoserological traits) for their offspring, by mating polyandrously. We predicted that extra-pair young (EPY) should show greater immune responsiveness and better body condition than their within-pair maternal half-siblings (WPY). Contrary to our prediction, WPY had higher cutaneous immune activity than their EPY brood-mates in two of three years, and EPY and WPY did not differ in measures of innate and humoral immunity. WPY also had higher albumin to γ-globulin ratios than EPY; however, they were not in better condition based on other measures. EPY had consistently longer tarsi (a measure of long-bone size) than their WPY half-siblings, suggesting that females engage in extra-pair copulations with larger males. The benefits of large structural size in the study population is unknown, but based on evidence from other passerines, we suggest that structural size may be an important fitness-related trait in house wrens. We conclude that our results are not consistent with the hypothesis that females gain immune-related benefits for their offspring by engaging in extra-pair matings. Further study of the fitness consequences of differences in tarsus length is needed to determine whether females acquire size-related benefits for their offspring from extra-pair mates.     

灰喜鹊摄食对中国沙棘种子萌发的影响

为了探明鸟类摄食中国沙棘果实后对中国沙棘种群扩散的作用,对①来自鸟粪肥的种子。②人工用酸和高温处理的种子和③作为对照的天然种子的萌发率和萌发速度进行比较,3种类型的种子均区分为具内果皮种子和不具内果皮种子两组。结果表明：酸性和高温环境对两种类型种子的萌发率影响不大,但中国沙棘果实的内果皮不仅使种子萌发推迟,而且还降低了种子的萌发率。灰喜鹊的消化作用虽然降低了中国沙棘种子的萌发率和萌发速度,但对中国沙棘种子的传播和种群的扩散仍有促进作用。     

The evolution of paternity and paternal care in birds

Paternity has been hypothesized to be related to the evolutionof paternal care because (1) there should be selection formales not to invest in broods with an uncertain parentage,or (2) male extrapair activity is traded against paternal care.We used interspecific comparisons to discriminate between these alternatives. Male participation in three kinds of parentalcare (nest building, incubation, provisioning of offspring)increased with high paternity in their own nests. Male parentalactivities at some stages of the breeding cycle were significantlycorrelated. A multivariate analysis taking this intercorrelationbetween different components of care and potentially confoundingvariables such as precociality, polyandry, and sexual dichromatism into account revealed that paternity was significantly positivelyrelated to offspring provisioning, while male participationin the other components of parental care did not explain asignificant amount of interspecific variation in paternity.Analyses of evolutionary transitions between different dichotomizedstates of paternity and paternal care provided no clear conclusionsconcerning evolutionary scenarios. However, theoretical arguments and the results of the contrast analyses suggest that male provisioningof offspring evolved in response to paternity.     

Parentage assignment and extra-group paternity in a cooperative breeder: the Seychelles warbler (Acrocephalus sechellensis)

We describe the development and initial application of a semiautomated parentage testing system in the Seychelles warbler (Acrocephalus sechellensis). This system used fluorescently labelled primers for 14 polymorphic microsatellite loci in two multiplex loading groups to genotype efficiently over 96% of the warbler population on Cousin island. When used in conjunction with the program CERVUS, this system provided sufficient power to assign maternity and paternity within the Seychelles warbler, despite the complications associated with its cooperative breeding system and a relatively low level of genetic variation. Parentage analyses showed that subordinate 'helper' females as well as the dominant 'primary' females laid eggs in communal nests, indicating that the Seychelles warbler has an intermediate level of female reproductive skew, in between the alternative extremes of helper-at-the-nest and joint nesting systems. Forty-four per cent of helpers bred successfully, accounting for 15% of all offspring. Forty per cent of young resulted from extra-group paternity.     

Molecular insight into patterns of colony composition and paternity in the common mole-rat Cryptomys hottentotus hottentotus

We report the discovery of intraspecific variation in both colony composition and patterns of paternity in two populations of the social common mole-rat Cryptomys hottentotus hottentotus. These two populations represent the mesic and arid habitat extremes of the species' broad ecological range in South Africa. Until recently colonies of the common mole-rat were thought to consist of familial groups whereby all colony members were the offspring of a monogamous reproductive pair. The remaining colony members were thought to forego reproduction until both social and ecological conditions favoured dispersal and opportunities for independent outbreeding. Results from genetic assignment tests using microsatellite markers indicate that while colony composition is dominated by familial groups, colonies within both populations included both adult and subadult foreign conspecifics. Analysis of parentage reveals that the social organization of C. h. hottentotus is not that of strict monogamy; paternity of offspring was not assigned consistently to the largest, most dominant male within the colony. Moreover, a number of significantly smaller males were found to sire offspring, suggesting a sneak-mating strategy by subordinate within-colony males. Extra-colony extra-pair paternity (ECP) was also found to characterize C. h. hottentotus colonies, occurring with similar frequencies in both habitats. Both dominant established breeding males and subordinate males were identified as siring young in nonsource colonies. Furthermore, established breeding males were found to sire extra-colony young in the same season as siring young within their source colonies. We discuss the significance of these results within the context of the divergent ecological regimes characterizing the two sites and observe that our results revisit the accuracy of using behavioural and morphological characters, which have structured the basis of our understanding of the behavioural ecology of this species, as indicators of breeding status in mark-recapture studies.