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1.
In polygynous species, males appear to gain additional offspring by pairing with multiple females simultaneously. However, this may not be true if some females copulate outside of the social pair bond. Polygynous males could experience lower paternity because of trade-offs among gaining multiple social mates, guarding fertility with these mates, and pursuing extra-pair matings. Alternatively, polygynous males could simultaneously gain extra social mates and have high paternity, either because of female preferences or because of male competitive attributes. We tested four predictions stemming from these hypotheses in a facultatively polygynous songbird, the dickcissel (Spiza americana). Unlike most previous studies, we found that males with higher social mating success (harem size) also tended to have higher within-pair paternity and that the number of extra-pair young a male sired increased significantly with his social mating success. Females that paired with mated males were not more likely to produce extra-pair young. In contrast, extra-pair paternity was significantly lower in the nests of females whose nesting activity overlapped that of another female on the same territory. This pattern of mating was robust to differences in breeding density. Indeed, breeding density had no effect on either extra-pair mating or on the association between polygyny and paternity. Finally, nest survival increased with harem size. This result, combined with the positive association between polygyny and paternity, contributed to significantly higher realized reproductive success by polygynous male dickcissels. 相似文献
2.
Relatedness, polyandry and extra-group paternity in the cooperatively-breeding white-browed scrubwren (Sericornis frontalis ) 总被引:3,自引:0,他引:3
Linda A. Whittingham Peter O. Dunn Robert D. Magrath 《Behavioral ecology and sociobiology》1997,40(4):261-270
We used DNA fingerprinting to examine the genetic parentage and mating system of the cooperatively breeding white-browed
scrubwren, Sericornis frontalis, in Canberra, Australia. Our analyses revealed a remarkable variety of mating tactics and social organization. Scrubwrens
bred in pairs or multi-male groups that consisted of a female and two or more males. Females were always unrelated to the
pair male or alpha (dominant) male. Among multi-male groups we found three different mating tactics. Firstly, when alpha and
beta (subordinate) males were unrelated, they usually shared paternity in the brood. This resulted in both males gaining reproductive
benefits directly. Secondly, when beta males were not related to the female but were related to the alpha males, beta males
sired offspring in some broods. In this situation, beta males gained reproductive benefits both directly and potentially indirectly
(through the related alpha male). Thirdly, when beta males were related to the female or both the female and alpha male, they
remained on their natal territory and did not sire any offspring. Thus beta males gained only indirect reproductive benefits.
Overall, when group members were related closely, the dominant male monopolized reproductive success, whereas when the members
were not related closely the two males shared paternity equally. This positive association between monopolization of reproduction
and relatedness is predicted by models of reproductive skew, but has not been reported previously within a single population
of birds. Other cooperatively breeding birds with both closely related and unrelated helpers may show a similar variety of
mating tactics. Finally, we found that extra-group paternity was more common in pairs (24% of young) than in multi-male groups
(6%), and we discuss three possible reasons for this difference.
Received: 21 May 1996 / Accepted after revision: 14 December 1996 相似文献
3.
Factors that affect extra-pair mating in birds are likely to vary across the breeding season. Changing densities of active
nests may alter the opportunities for extra-pair mating, and parental duties may alter a male’s opportunity to guard his mate
from extra-pair mating. The latter affects species with multiple broods, where males care for fledglings from first nests
while females initiate second nests. We studied a population of multi-brooded American robins (Turdus migratorius) to assess how seasonal changes in nesting density and changes in mate-guarding opportunity influenced paternity patterns
over successive breeding attempts. Extra-pair paternity (EPP) occurred in 71.9% of broods and accounted for 48.1% of young.
High nesting densities in the study population may explain the high overall rate of EPP, but seasonal variation in breeding
density did not explain patterns of EPP among nests. Contrary to the predictions of the mate-guarding hypothesis, EPP did
not increase in the second nests that followed successful first nests, and the percentage of extra-pair young in second nests
did not decline as the overlap between successive nests increased. The fact that EPP was actually lower when the interval
between clutches was shorter suggests that the sooner the males can assume sole care of first broods and allow their mates
to renest (indicative of superior paternal quality), the more paternity they realize in the next nest. These results suggest
that mate-guarding opportunity does not influence paternity in this population of American robins and that female robins may
allocate paternity based on their assessment of male parental performance at first nests. 相似文献
4.
Mating system of the cooperatively breeding noisy miner Manorina melanocephala,as revealed by DNA profiling 总被引:1,自引:0,他引:1
In this study we examined parentage within broods of the cooperatively breeding noisy miner using multi-locus DNA profiling. Previous studies of noisy miners described them as highly promiscuous, leading to the suggestion that promiscuous mating behaviour was a tactic used by females to recruit males as provisioners to their nests (Dow 1978). At our study site in south-east Queensland, Australia, we found that both multiple and extra-group paternity (i.e. a female mating with a male outside the group of male provisioners at her nest) were rare. In nests where multiple paternity was possible (i.e. clutch size > 1) 97% of 31 broods were sired by only a single male. Overall, 96.5% of all nestlings (n = 85) were the result of monogamous matings. Also, at the vast majority of nests, the male that sired the nestlings was also the main provisioner among all male nest attendants. Our results show that the mating system of the noisy miner can no longer be considered cooperative polyandry (Brown 1987) but is clearly genetic monogamy. We discuss the implications of this finding for understanding the complex social system of this species. 相似文献
5.
Subordinate males are more likely to help if unrelated to the breeding female in cooperatively breeding white-browed scrubwrens 总被引:2,自引:0,他引:2
Subordinates in communally breeding groups of birds usually help to provision nestlings, but in some species helping-at-the-nest
is facultative. In species in which groups usually contain relatives, subordinates either always feed young or are more likely
to do so when breeding dominants are close relatives, suggesting that benefits of helping collateral kin are important. In
other species, adult group members are unrelated to each other and males may only feed young if they have gained paternity,
showing that cooperation is related to the mating system. The white-browed scrubwren, Sericornis frontalis, is a communally breeding species in which most groups consist of a simple pair or a dominant pair with a subordinate male.
Subordinate males either fed nestlings in a given nest at a rate comparable to the dominants, or did not feed them at all.
Breeding groups usually formed through natal philopatry of males, so that about 80% of subordinates were closely related to
one or both members of the dominant pair. However, because of death and dispersal, 54% of subordinates were unrelated to the
resident female. Although subordinates with their mother fed nestlings in 48% of cases, they fed offspring in 75% of cases
if their mother had been replaced by an unrelated female, suggesting that their decision to help is influenced by the opportunity
to mate with the female. Supporting this conclusion, relatedness to the dominant male did not affect subordinate behaviour,
and genetic studies showed that subordinates often gained paternity if unrelated to the female. Thus, paradoxically, provisioning
nestlings is related to the opportunity for mating in a society in which there is natal philopatry and subordinates are usually
related to one or both members of the dominant pair.
Received: 25 January 1997 / Accepted after revision: 1 May 1997 相似文献
6.
In cooperative breeders, mature males may compete for fertilizations. In this study, we measured the degree of multiple paternity
in a natural population of a cooperatively breeding fish. Neolamprologus pulcher (Perciformes: Cichlidae) is a highly social cichlid endemic to Lake Tanganyika. We used highly variable microsatellite loci
to survey 12 groups with an average number of 10.6 brood care helpers per group and a total of 43 offspring (mean 3.6 per
brood). In 11 of 12 groups, all young were assigned to the dominant female. The dominant male sired all offspring in three
groups, part of the offspring in four groups, and in five groups, he had no paternity at all. In total, 44.2% of young were
not fathered by the current male territory owner. Multiple paternity was found in 5 of 12 broods (41.7 %), with 8 of 35 young
(22.9 %) being sired by males other than the respective territory owners. This is an exceptionally high rate of extra-pair
paternity among cooperatively breeding vertebrates. Neither helpers present in these territories during collection nor neighbouring
males were unequivocally assigned to have sired these extra-pair young. However, behavioural observations suggest that male
helpers may have produced these young before being expelled from the territory in response to this reproductive parasitism.
We discuss these results in the light of reproductive skew theory, cooperative breeding in vertebrates and alternative reproductive
tactics in fish. 相似文献
7.
Lauryn Benedict 《Behavioral ecology and sociobiology》2008,62(6):983-988
Previous studies suggest that extrapair young are very rare or absent in socially monogamous avian species that produce vocal
duets. These results are generally consistent with functional hypotheses suggesting that duets may signal commitment between
partners, or aid males as a paternity guard to ensure genetic as well as social monogamy. Additionally, species that exhibit
social monogamy with the same partner across multiple breeding seasons tend to exhibit low levels of extrapair paternity,
so duetting species that mate for life may be particularly likely to exhibit genetic monogamy. This study examined the social
and genetic mating systems of California towhees (Pipilo crissalis), a duetting species thought to have life-long pair bonds. Observation of a color-banded population confirmed that California
towhees exhibit long-term social monogamy. Known social families were genotyped at four microsatellite loci with high allelic
diversity. Unexpectedly, paternity exclusion indicated that at least 13 of 31 (42%) nests contained extrapair young. All chicks
exhibited maternal alleles, but 21 of 81 (26%) young were not the offspring of social fathers. Thus, in contrast to previous
work, this study documents high frequencies of extrapair young among socially monogamous duetting birds with long-term pair
bonds. 相似文献
8.
Reproduction by subordinates in cooperatively breeding Arabian babblers is uncommon but predictable 总被引:4,自引:0,他引:4
In a genetic analysis of the mating system of cooperatively breeding Arabian babblers (Timalidae: Turdoides squamiceps), we identified which individuals in the population are breeding, and how reproductive success was distributed among group
members with respect to their dominance rank, for both males and females. The population was characterized by an asymmetrical
distribution of reproductive success; behaviorally dominant males produced 176 of 186 (95%) of the offspring in 44 social
groups analyzed, and alpha females produced 185 of 186 (99.5%). We evaluated models of reproductive skew by examining genetic
and demographic correlates of reproduction by␣subordinates. Subordinate (beta) males that sired young were more likely to
be recent dispersers from their natal groups or members of newly formed groups than betas that did not reproduce. Breeding
beta males had spent smaller proportions of their lives with the current alpha male and female as alphas than had beta males
that did not sire young. One consequence of the linkage of dispersal with breeding in newly formed, nonnatal groups is that
beta males that sired young had significantly lower genetic similarity to the alpha males in their groups (based on band-sharing
coefficients using multilocus minisatellite DNA fingerprinting) than those that did not sire young. This pattern may occur
generally in species in which group membership accrues both through nondispersal of young (forming groups of relatives) as
well as through dispersal involving coalitions that sometimes include nonrelatives.
Received: 22 July 1997 / Accepted after revision: 5 February 1998 相似文献
9.
Giulia Cutuli Stefano Cannicci Marco Vannini Sara Fratini 《Behavioral ecology and sociobiology》2013,67(2):273-281
Sperm storage is widespread in many vertebrate groups, and it is frequently associated with promiscuous mating systems. Chelonian species are one of the most outstanding examples of a promiscuous group capable of long-term sperm storage; specialized structures have evolved within the oviducts of these vertebrates to ensure sperm vitality across reproductive cycles. Thus far, few studies have investigated the factors regulating multiple paternity, sperm usage by females and paternity distribution in successive clutches. This study aimed to investigate the effect of mating order on male mounting and reproductive success in Testudo hermanni hermanni, combining behavioural and genetic data. A series of planned matings were performed, within which experimental females were mated sequentially to two different males under controlled conditions. Observations conducted during experimental matings revealed that courtship displays did not significantly differ between the first and second males to mate with a female. Interactions ending with a mount were characterized by a significantly higher intensity and occurrence of determinate courtship behaviours, for example biting and running after the female. Paternity analysis performed on hatchlings produced from experimental females revealed that 46 % of the clutches were multi-sired. A significant contribution of previous years' partners was still found, thus confirming the long-term sperm storage within the female oviduct in this species. Finally, mating order did not significantly affect the reproductive success of experimental males during the on-going reproductive season. 相似文献
10.
Female control of reproductive skew in cooperatively breeding brown jays (<Emphasis Type="Italic">Cyanocorax morio</Emphasis>) 总被引:2,自引:0,他引:2
Brown jays (Cyanocorax morio) are long-lived, social corvids that live in large, stable, territorial groups (mean = 10 individuals). In this study, I determined the distribution of reproductive success within groups using multi-locus DNA fingerprinting. Breeding females produced virtually all (99%) of the young within their own nests. Reproduction within groups was highly skewed towards a single primary female, although long term data indicate that secondary females (female breeders that were usually younger and subordinate to the primary female) were sometimes successful. The high reproductive skew observed for females was associated with primary female aggression. Successful reproduction by secondary females may have been due to parental facilitation or the inability of primary females to completely suppress secondary females. Multiple paternity occurred in 31–43% of broods and extra-group paternity occurred in a minimum of 22% of broods. Patterns of paternity also varied between years, since females often switched or included new genetic mates. Although male consorts of nesting females fathered relatively few offspring (20%), they still had a higher chance of fathering offspring than any other single group male. Reproduction was less skewed for males than females as a result of female mating patterns. Female reproductive patterns are consistent with some of the predictions and assumptions from optimal skew models, while male reproductive patterns are not. The factors affecting skew in species with complex social systems such as incomplete control by breeders over subordinate reproduction, female control of paternity, and resource inheritance have not been well incorporated into reproductive skew models.Communicated by: J. Dickinson 相似文献
11.
Patricia Brekke Phillip Cassey Cristina Ariani John G. Ewen 《Behavioral ecology and sociobiology》2013,67(6):963-972
Sexual conflict can result in the evolution of extreme mating strategies, including forced copulation. Forced extrapair copulation (FEPC) is generally rare among birds, but is common in re-introduced populations of the hihi (Notiomystis cincta), a socially monogamous, New Zealand endemic, endangered passerine. The aim of this study was to understand the patterns of extrapair paternity in a population where the majority of EPC is forced and to examine the factors, in particular female-specific, influencing the proportion of offspring fathered by extrapair males (EPP—extrapair paternity) and the number of males siring extrapair offspring within a brood (EPM) in this species. Using 8 years of comprehensive paternity, life-history and demographic information for 485 breeding attempts, we show that the frequency of EPP is dependent on (1) social male and female age, (2) the month the female fledged, (3) breeding density and (4) whether it was their first or second reproductive event of the season. In addition, we show that both EPP and EPM are negatively associated with breeding synchrony and clutch size is the most important predictor of EPM. Understanding the drivers of EPP and EPM in species with FECP is important because these are strong determinants of variance in reproductive success and the maintenance of extreme mating behaviour. 相似文献
12.
In a recent review, Westneat and Stewart (2003) compiled evidence that extra-pair paternity results from a three-player interaction in which sexual conflict is a potent force. Sequentially polyandrous species of birds appear to fit this idea well. Earlier breeding males may attempt to use sperm storage by females to obtain paternity in their mates subsequent clutches. Later-breeding males may consequently attempt to avoid sperm competition by preferring to pair with previously unmated females. Females may bias events one way or the other. We examined the applicability of these hypotheses by studying mating behavior and paternity in red-necked phalaropes (Phalaropus lobatus), a sex-role reversed, socially polyandrous shorebird. Male red-necked phalaropes guarded mates more strongly than other shorebirds. Males increased within-pair copulation attempts during their mates fertile period, and maintained or further increased attempts towards the end of laying, suggesting an attempt to fertilize the females next clutch; these attempts were usually thwarted by the female. Paired males sought extra-pair copulations with females about to re-enter the breeding pool. Multilocus DNA fingerprinting showed that 6% of clutches (4/63) each contained one chick sired by a male other than the incubator, producing a population rate of these events of 1.7% (n=226 chicks). Male mates had full paternity in all first clutches (n=25) and 15 of 16 monogamous replacement clutches. In contrast, 3 of 6 clutches of second males contained extra-pair young likely fathered by the females previous mate. Previously mated female phalaropes may employ counter-strategies that prevent later mating males from discriminating against them. The stability of this polyandrous system, in which males provide all parental care, ultimately may depend on females providing males with eggs containing primarily genes of the incubating male, and not a previous mate.Communicated by M. Webster 相似文献
13.
Mating patterns and reproductive success in the bushy-tailed woodrat (Neotoma cinerea), as revealed by DNA fingerprinting 总被引:1,自引:0,他引:1
The mating patterns and reproductive success of the bushy-tailed woodrat (Neotoma cinerea) were investigated over a 3-year period (1992–1994) using DNA fingerprinting. Paternity was determined by genetic analysis
of 58 juveniles of known maternity from 35 litters. Analysis of DNA fingerprints revealed that all offspring within a litter
were fathered by a single male; the statistical probability of detecting multiple males mating with a female was high, indicating
that multiple paternity would have been detected had it occurred. However, individual males did not father more than one litter
from a given female either within or between years. At least 75% of females and 57% of males successfully produced offspring
each year. The finding that all littermates are first-order relatives may contribute to the high level of female cooperation
in this species.
Received: 28 May 1997 / Accepted after revision: 22 March 1998 相似文献
14.
Masashi Kiyota Stephen J. Insley Stacey L. Lance 《Behavioral ecology and sociobiology》2008,62(5):739-746
We conducted a 6-year longitudinal behavioral and genetic investigation of a highly polygynous pinniped, the northern fur
seal (Callorhinus ursinus), to determine the contribution of terrestrial polygyny to male fertilization success and to assess the occurrence of alternative
mating strategies. Genetic samples from 37 adult males, 50 adult females, and 85 pups were collected and genotyped using five
polymorphic microsatellite loci. Pup paternity was assigned using Cervus 2.0 at 99% confidence level. Paternity of 83 pups
(98%) was assigned to terrestrial males who held territories or stayed temporarily in the study area during the breeding season
when fertilization occurred. For 56 pups of which attendance records of their mothers were available, paternity of 45 pups
(80%) was assigned to the associate males in whose territory their mothers stayed during the perioestrus period. In addition
to defending breeding territories, territorial males have often been observed attempting to forcibly abduct adult females
from adjacent territories (female stealing): We observed a total of 95 such cases, in which the stealers had significantly
fewer females than the territorial males from whose territories they stole females. Our results indicate that terrestrial
resource-defense polygyny is the major mating system in this species and that nonassociated paternity occurs mostly as a result
of alternative mating strategies of less successful males. Male northern fur seals thus appear to adopt conditional alternative
strategies that depend on their current social status to maximize their life-time reproductive success. 相似文献
15.
Condition-dependent control of paternity by female purple martins: implications for coloniality 总被引:9,自引:0,他引:9
Proposed causal links between extra-pair copulation (EPC) and colony formation in socially monogamous birds hinge on the
question of which sex controls fertilizations. We examined in colonial purple martins Progne subis (1) whether EPCs were forced or accepted by females, and (2) the degree to which apparently receptive females were able to
obtain EPCs against their mates’ paternity defenses. Paternity analyses of multilocus DNA fingerprinting confirmed previous
findings of a marked relationship between age class and extra-pair fertilizations (EPFs), with young males losing paternity
of 43% (n = 53) of their putative offspring compared to 4% (n = 85) by old males. All assignable extra-pair offspring were sired by old males, with one male obtaining most EPFs each year.
Contrary to the hypothesis that EPCs are forced, EPF frequency within age class did not increase with seasonal increases in
the number of males per fertile female. Whereas the male control hypothesis predicted that the male age class that mate-guarded
more would be cuckolded less, the reverse was true: young males guarded significantly more intensely. The male age class difference
in cuckoldry could not be explained by the possibility that young and inexperienced females (which are usually paired to young
males) were more vulnerable to forced copulation because EPFs were unrelated to female age. These findings suggest that females
(1) pair with old males and avoid EPCs, or (2) pursue a mixed mating strategy of pairing with young males and accepting EPCs
from old males. The receptivity to EPCs by females paired to young males put them in conflict with their mates. Two factors
determined the paternity achieved by young males: (1) the relative size of the male to the female, with young males achieving
much higher paternity when they were larger than their mates, and (2) the intensity of mate-guarding. Both variables together
explained 77% of the variance in paternity and are each aspects of male-female conflict. Given female receptivity to EPCs,
mate-guarding can be viewed as male interference with female mating strategies. We conclude that EPCs are rarely or never
forced, but the opportunity for females paired to young males to obtain EPCs is relative to the ability of their mates to
prevent them from encountering other males. Evidence of mixed mating strategies by females, combined with other features of
the martin mating system, is consistent with the female-driven “hidden lek hypothesis” of colony formation which predicts
that males are drawn to colonies when females seek extra-pair copulations.
Received: 23 March 1995/Accepted after revision: 14 January 1996 相似文献
16.
Manakorn Sukmak Worawidh Wajjwalku Julia Ostner Oliver Schülke 《Behavioral ecology and sociobiology》2014,68(7):1097-1108
In groups with multiple males, direct mate competition may select for the evolution of dominance hierarchies that sort males into a queue for access to fertile females. The priority-of-access (PoA) model proposed by Altmann in 1962 makes explicit predictions about the resulting paternity distribution based on an interaction between male dominance rank and the overlap of female receptive phases. Here, we investigated whether the logic of the PoA model predicted the distribution of paternity across ranks in a seasonal breeder with high reproductive synchrony over six consecutive mating seasons. We studied 18 males that resided in a group of wild Assamese macaques (Macaca assamensis) in their natural habitat at Phu Khieo Wildlife Sanctuary, Thailand, between 2006 and 2011 with 5 to 13 conceptions per season. We assessed whether mate guarding increased paternity success, described “short-term” deviations from predicted paternity distribution, and examined how these are related to the number of competitors and fertile females. We determined genetic paternity of 43 (93 %) offspring born into the study group and found reproductive skew to be relatively low with 29 % alpha male paternity in accordance with the high degree of female reproductive synchrony observed. Short-term deviations from expected paternity distribution over ranks were not explained by the number of resident males or the number of conceiving females or their interaction. Within the limits of this study, these results suggest that even if males cannot discern female fertile phases, if reproduction is seasonal, and if reproductive synchrony is high, males may also compete directly over access to females. 相似文献
17.
Kelley J. Kissner Patrick J. Weatherhead H. Lisle Gibbs 《Behavioral ecology and sociobiology》2005,59(2):207-214
To resolve conflicting field observations regarding the action of sexual selection, we used breeding experiments and paternity analysis of the 927 resulting offspring to assess how male size, condition, tail length, genetic similarity to the female, and variation in operational sex ratio (OSR) affected male reproductive success and the incidence of polyandry in northern watersnakes (Nerodia sipedon). Only size affected male mating success. Large males were more successful, but only when male size varied substantially and competition among males was intense (i.e., male-biased OSR). The conditional nature of the size advantage may explain why studies of free-living watersnakes have produced inconsistent results regarding the relationship between male size and mating success. Size differences between males did not affect the proportion of offspring each male sired within multiply sired litters. We found positive size-assortative mating, but only when the OSR was female biased, suggesting that smaller males had improved access to females when competition among males was reduced, but that competition with larger males still restricted mating opportunities of small males to less preferred, smaller females. Most litters (58%) were multiply sired and larger females were more likely to produce multiply sired litters, similar to free-living watersnakes. There was no association between the incidence of multiple paternity and OSR, however, suggesting that polyandry is not simply a function of opportunity, with females passively waiting for males to court them. 相似文献
18.
Patrick J. Weatherhead 《Behavioral ecology and sociobiology》1997,40(3):151-158
Using data from a 6-year paternity study of red-winged blackbirds, I tested the hypotheses that increased nesting synchrony
should either promote extra-pair mating by increasing the advantage of extra-pair mating to females, or decrease extra-pair
mating by constraining males from seeking extra-pair copulations. Contrary to these hypotheses, the occurrence of extra-pair
paternity did not vary with nesting synchrony over the breeding season, or vary with the number of synchronous nests within
territories or within marshes, or with nesting order on territories. However, for nearly all nests with extra-pair young,
there were fewer females synchronous with that nest on the cuckolder's territory than on the territory of the cuckolded male.
This “advantage” of a synchrony difference was less pronounced for older males that cuckolded younger males, particularly
when the two males were not neighbors. Collectively, these results suggest that breeding synchrony affects extra-pair mating
by affecting mate guarding, but that breeding synchrony alone can not be used to predict which females are more likely to
engage in extra-pair mating, nor with which extra-pair males they will mate. Understanding why extra-pair mating by older
males is less affected by breeding synchrony may explain much about both the proximate and ultimate causes of extra-pair mating
in red-winged blackbirds.
Received: 7 June 1996 / Accepted after revision: 25 November 1996 相似文献
19.
Antje Engelhardt Michael Heistermann J. Keith Hodges Peter Nürnberg Carsten Niemitz 《Behavioral ecology and sociobiology》2006,59(6):740-752
One of the basic principles of sexual selection is that male reproductive success should be skewed towards strong males in
species with anisogamous sex. Studies on primate multi-male groups, however, suggest that other factors than male fighting
ability might also affect male reproductive success. The proximate mechanisms leading to paternity in multi-male primate groups
still remain largely unknown since in most primate studies mating rather than reproductive success is measured. Furthermore,
little research focuses on a female’s fertile phase. The aim of this study was to investigate the relative importance of male
monopolisation and female direct mate choice for paternity determination. We also investigated the extent to which paternity
was decided post-copulatory, i.e. within the female reproductive tract. We used a combined approach of behavioural observations
with faecal hormone and genetic analysis for assessment of female cycle stage and paternity, respectively. The study was carried
out on a group of wild long-tailed macaques living around the Ketambe Research Station, Gunung Leuser National Park, Indonesia.
Our results suggest that both male monopolisation and post-copulatory mechanisms are the main determinants of male reproductive
success, whereas female direct mate choice and alternative male reproductive strategies appear to be of little importance
in this respect. Female cooperation may, however, have facilitated male monopolisation. Since paternity was restricted to
alpha and beta males even when females mated with several males during the fertile phase, it seems that not only male monopolisation
but also post-copulatory mechanisms may operate in favour of high-ranking males in long-tailed macaques, thus reinforcing
the reproductive skew in this species. 相似文献
20.
Multiple paternity and offspring quality in tree swallows 总被引:1,自引:0,他引:1
Peter O. Dunn Jan T. Lifjeld Linda A. Whittingham 《Behavioral ecology and sociobiology》2009,63(6):911-922
There is mounting evidence in a variety of taxa that females increase offspring quality by mating with multiple males, often
resulting in multiple paternity. In birds, however, few studies have explicitly examined the benefits of mating with several
different males; instead, the focus has been on whether or not extra-pair mating occurs, and its adaptive significance remains
controversial. We examined the hypothesis that offspring quality, particularly immune response (phytohaemagglutinin assay)
and growth, increases with the number of sires in broods of socially monogamous tree swallows (Tachycineta bicolor). We found one of the highest known levels of multiple paternity in birds (84% of nests with two or more extra-pair young
had at least two extra-pair sires). Among nests with extra-pair young, the number and diversity of sires continued to increase
linearly with the number of extra-pair young, so there was no evidence that some males monopolized paternity at high levels
of extra-pair fertilization. Indeed, the number of sires was actually greater than expected in large broods, suggesting that
some females might be seeking more mates. We found no effect of the number of sires on nestling immune response or growth.
In mixed paternity broods, the immune response of extra-pair young did not differ from that of their within-pair half-siblings.
However, among all broods, nestlings had a stronger immune response in nests with at least one extra-pair nestling than in
nests with all within-pair nestlings. These results are not consistent with a good genes benefit of extra-pair mating, but
they do suggest that there are environmental effects associated with extra-pair mating that increase nestling immune response.
These environmental effects could produce indirect genetic effects on sexual selection if they are heritable. The extraordinarily
high number of sires in this species highlights a relatively unexplored source of sexual selection in birds. 相似文献