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1.
Brood sex ratios, female harem status and resources for nestling provisioning in the great reed warbler (Acrocephalus arundinaceus) 总被引:4,自引:0,他引:4
H. Westerdahl Staffan Bensch Bengt Hansson Dennis Hasselquist Torbjörn von Schantz 《Behavioral ecology and sociobiology》2000,47(5):312-318
The theory of parental investment and brood sex ratio manipulation predicts that parents should invest in the more costly
sex during conditions when resources are abundant. In the polygynous great reed warbler, Acrocephalus arundinaceus, females of primary harem status have more resources for nestling provisioning than secondary females, because polygynous
males predominantly assist the primary female whereas the secondary female has to feed her young alone. Sons weigh significantly
more than daughters, and are hence likely to be the more costly sex. In the present study, we measured the brood sex ratio
when the chicks were 9 days old, i.e. the fledging sex ratio. As expected from theory, we found that female great reed warblers
of primary status had a higher proportion of sons in their broods than females of lower (secondary) harem status. This pattern
is in accordance with the results from two other species of marsh-nesting polygynous birds, the oriental reed warbler, Acrocephalus orientalis, and the yellow-headed blackbird Xanthocephalus xanthocephalus. As in the oriental reed warbler, we found that great reed warbler males increased their share of parental care as the proportion
of sons in the brood increased. We did not find any difference in fitness of sons and daughters raised in primary and secondary
nests. The occurrence of adaptive sex ratio manipulations in birds has been questioned, and it is therefore important that
three studies of polygynous bird species, including our own, have demonstrated the same pattern of a male-biased offspring
sex ratio in primary compared with secondary nests.
Received: 1 June 1999 / Received in revised form: 10 January 2000 / Accepted: 12 February 2000 相似文献
2.
Corey R. Freeman-Gallant 《Behavioral ecology and sociobiology》1997,40(6):395-400
Empirical relationships between parentage and male parental care are commonly interpreted in the context of life-history
models that consider increased offspring survivorship as the only benefit of paternal effort. However, indirect benefits associated
with male care can also influence a male's response to cuckoldry: if females allocate paternity according to their prior experience
with male parental care, it may pay for males to provision extra-pair young in early broods. Here, I assess the relationship
between first-brood parentage and paternal care in a population of Savannah sparrows (Passerculussandwichensis) where a male's fertilization success in the second brood appears to be influenced by his prior parental performance. Based
on the multi-locus DNA fingerprinting of 17 first broods, male feeding effort was influenced by parentage (percent of brood
resulting from within-pair fertilizations) but not by brood size, male mating status (monogamous versus polygynous), timing
of breeding (hatching date), structural size (wing length) or condition (mass). Males provided more care to broods that contained
few within-pair young. This result supports the idea that males provision young to increase their future mating success, but
alternative hypotheses involving male quality and timing of breeding cannot be excluded.
Received: 13 August 1996 / Accepted after revision: 22 February 1997 相似文献
3.
A. D. Tucker H. I. McCallum C. J. Limpus K. R. McDonald 《Behavioral ecology and sociobiology》1998,44(2):85-90
We compared natal dispersals of freshwater crocodiles (Crocodylus johnstoni) against the prediction of male dispersal bias for a polygynous mating system. The crocodiles inhabited a linear series of
pools and we calculated the net distances from natal pools to recapture locations some 12–18 years later, at maturity. Philopatry
was assessed in terms of adult social distances. A female social distance was 0.46 pools and a male social distance was 1.0
pool. By these criteria, both sexes showed low levels of philopatry (7–12%). However, individuals of both sexes dispersed
from the natal site long before they were sexually mature. Divergence in dispersal patterns by sex occurred after the maturity
threshold, as males dispersed two to three times farther than females. Intrasexual competition by males is resolved by a size-based
hierarchy. The displacement of small males from local mating access is a probable cause of the longer dispersals undertaken
by males. Competition, rather than inbreeding avoidance, is driving dispersal in this population of freshwater crocodiles.
Received: 8 May 1998 / Accepted after revision: 26 June 1998 相似文献
4.
Social monogamy and extra-pair fertilization in an Australian lizard, Tiliqua rugosa 总被引:3,自引:0,他引:3
C. Michael Bull Steven J. B. Cooper Ben C. Baghurst 《Behavioral ecology and sociobiology》1998,44(1):63-72
This study investigates social monogamy in the Australian sleepy lizard, Tiliqua rugosa. At a 70-ha site near Mount Mary, South Australia, we radio tracked 55 adult female and 39 adult male lizards during their
spring activity periods. Each lizard was observed in 1–5 years. Females were observed with a single male partner on an average
of 10.8 days per year, although in 17.3% of cases, females were observed on 2 or fewer days with a male. The most intense
pairing period each year was 15 September–15 November when females were with male partners on an average of 36% of observation
days. Partnerships lasted an average of 43.3 days each year. After mating in early November, the pairs separated. Observations
of females pairing with other males were rare. Most males (82%) were also consistently monogamous, although 7 were observed
pairing with 2 females within one season. To investigate paternity, we allowed 21 gravid females to give birth to 42 offspring
in the laboratory. We determined genotypes at five polymorphic microsatellite DNA loci for the females, their male partners
and their offspring. Four litters (19%) and 6 of the offspring from those litters (14.3%) showed evidence of extra-pair fertilization
(EPF). Although the sample sizes are small, females of polygynous males were more likely to experience EPF.
Received: 22 February 1998 / Accepted after revision: 23 May 1998 相似文献
5.
B. Birgersson 《Behavioral ecology and sociobiology》1998,43(2):87-93
This study tested whether fallow deer mothers, Dama dama, bias their investment towards sons and, thus, whether sons are more costly to produce than daughters. Young (2 years) and
old (≥3 years) hinds were analysed separately. Old hinds who raised sons accumulated less body mass than those who raised
daughters, during the period between late gestation and the end of lactation. This difference in body mass persisted to the
following spring. Mothers who had raised sons gave birth later and their offspring's pre-winter mass was lower the following
year than for mothers who had raised daughters. These results indicate higher expenditure for hinds who raise sons and support
theories of male-biased maternal investment. However, young mothers with sons and those with daughters did not differ in reproductive
performance the following year. One reason might be that young mothers are close to the maximum level of maternal expenditure,
since they are still growing, and cannot invest any extra resources in sons.
Received: 28 August 1997 / Accepted after revision: 5 April 1998 相似文献
6.
Alfréd Trnka Milica Po?gayová Petr Procházka Pavol Prokop Marcel Honza 《Behavioral ecology and sociobiology》2012,66(8):1187-1194
Reproductive success of brood parasites varies considerably both among and within host species, mainly due to differences in host egg-rejection rates and survival of parasitic chicks. Here, we investigated the breeding success of the cuckoo (Cuculus canorus) in one of its major hosts, the great reed warbler (Acrocephalus arundinaceus), with respect to host social mating status. In this passerine, polygynous males provide less parental care to their young per nest than monogamous males. Consequently, their less-assisted females may fledge lower numbers of nestlings than monogamous females. This may be especially true for secondary females, which often receive limited or no paternal help with young at all. Based on these findings, we expected higher cuckoo reproductive success in nests of socially monogamous than polygynous great reed warbler males. More specifically, we predicted lower fledging success of cuckoo young in nests of secondary than primary or monogamous females. In line with the prediction, we found higher cuckoo fledging success in nests of monogamous than polygynous males, monogamous nests being more than twice as successful as secondary nests. We detected, however, only a tendency to lower cuckoo success in primary compared to monogamous nests and no differences between primary and secondary nests. Moreover, neither parasitism nor host egg-rejection rates differed among the nests of different status. Our results show, for the first time, that the social mating status of a host may influence the overall reproductive success of a brood parasite and thus should be considered in further studies. 相似文献
7.
Jay D. Evans 《Behavioral ecology and sociobiology》1998,44(1):35-42
Most social groups have the potential for reproductive conflict among group members. Within insect societies, reproduction
can be divided among multiple fertile individuals, leading to potential conflicts between these individuals over the parentage
of sexual offspring. Colonies of the facultatively polygynous ant Myrmicatahoensis contain from one to several mated queens. In this species, female sexuals were produced almost exclusively by one queen.
The parentage of male sexuals was more complex. In accordance with predictions based on worker sex-allocation preferences,
male-producing colonies tended to have low levels of genetic relatedness (i.e., high queen numbers). Correspondingly, males
were often reared from the eggs of two or more queens in the nest. Further, over half of the males produced appeared to be
the progeny of fertile workers, not of queens. Overall investment ratios were substantially more male biased than those predicted
by genetic relatedness, suggesting hidden costs associated with the production of female sexuals. These costs are likely to
include local resource competition among females, most notably when these individuals are adopted by their maternal nest.
Received: 3 March 1998 / Accepted after revision: 20 June 1998 相似文献
8.
Most studies of social polygyny in birds have examined male provisioning on the basis of the number of feeding visits. This
may be misleading if males compensate for infrequent visits by bringing larger prey at each visit. We investigated nestling
provisioning in the socially polygynous great reed warbler, Acrocephalus arundinaceus, in south Central Sweden in 1996–1997. We collected data on rate of feeding visits, prey size and the amount of biomass delivered
by males and females. Males had lower rates of feeding visits and provided smaller prey to nestlings in secondary than in
monogamous and primary nests. Secondary females had higher rates of feeding visits and brought larger prey than monogamous
and primary females. These results confirm that secondary females face a potential cost of polygyny through a lower rate of
male feeding, and that this cost was reinforced by the significantly lower male provisioning rate (biomass h–1) at secondary nests. Secondary females compensated for the lack of male assistance by increasing their rate of feeding and
bringing larger prey. As a result, offspring in nests of secondary females received as much food as did those in nests of
primary females. Prey load size increased with the parent’s proportion of feeding visits, suggesting that parents use different
feeding strategies depending on their amount of responsibility for nestling provisioning. We suggest that parents which take
the main responsibility for nestling feeding have to forage further away from the nest, and based on optimal-foraging theory,
they should then on average bring larger prey to their nest.
Received: 4 April 1999 / Received in revised form: 12 October 1999 / Accepted: 23 October 1999 相似文献
9.
Changes in male guppy courting distance in response to a fluctuating light environment 总被引:1,自引:0,他引:1
In the guppy (Poecilia reticulata), effective courting by a male requires visual contact with the female. Therefore, environmental light intensity may affect
male display behavior, particularly initial courtship distance. We found that male guppies courted at exact and predictable
distances from the female given a particular light level, both in field and laboratory studies. In lower light levels (<0.1 μmol m−2 s−1), for example at dawn, dusk, or under heavy canopy, males court females at closer and less variable distances (<3 cm). At
higher light levels, which occur during most of the day and with less canopy cover, males often court from twice or three
times further out. Light levels over guppy streams change over relatively short time periods and ranges, correlating with
variation in courtship distances. Laboratory manipulations of irradiance confirmed that courtship distance depends on illumination.
Hence, courtship distances may be set by the effect of lighting on signal efficiency, minimization of energy or time expenditures,
or predation risk.
Received: 16 December 1997 / Accepted after revision: 8 August 1998 相似文献
10.
Nathaniel T. Wheelwright Cheryl B. Schultz Peter J. Hodum 《Behavioral ecology and sociobiology》1992,31(4):279-289
Summary To determine the effects of male mating status on female fitness, we compared the reproductive success, survival, and future fecundity of female Savannah sparrows (Passerculus sandwichensis) mated to monogamous vs. polygynous males in a 5-year study on Kent Island, New Brunswick, Canada. The proportion of males with more than one mate varied from 15 to 43% between years and sites. Polygynous and monogamous males fledged young of equal size in every year of the study. Females who shared paternal care with other females laid as many eggs per clutch and clutches per season as monogamously mated females. In most years polygynously mated females showed no delay in laying a second clutch, and they suffered no reduction in fecundity the following year. Recruitment of a female's offspring into the breeding population was generally independent of her mating status. Fitness costs of being mated to a polygynous male were only apparent in one year of the study, during which females mated to polygynous males had higher over-winter mortality than those mated to monogamous males. That same year, young raised by polygynous males were only one-third as likely to survive to reproductive maturity (as inferred by returns) as those raised by monogamous males. A male's mating status had no effect on his own survivorship. A male's mating status did not necessarily reflect his contributions to raising nestlings, which may partially explain why monogamously and polygynously mated females had equal fitness. At 35 nests the proportion of food deliveries brought by individual males varied from 0 to 75%; on average, males brought fewer than 30% of all food deliveries. Yet parental care by polygynous males was no less than that of monogamous males, at least at the nests of their primary females. Secondary females tended to receive less male assistance during the nestling stage, but their reproductive success was indistinguishable from that of primary females. Females feeding young without male assistance made as many food deliveries/h as did pairs in which males brought at least 30% of all food deliveries. Unassisted females did not suffer diminished fledging success or produce smaller fledglings. The benefits of polygyny for male Savannah sparrows are clear: polygynous males recruit more surviving offspring into the breeding population than monogamous males. The fitness of females, on the other hand, appears to be unaffected by whether their mate was monogamous or polygynous except in occasional years. Polygyny may be maintained in this population by the constraints of a female-biased sex ratio, the inability of females to predict a male's paternal care based on his morphology or behavior, the poor correlation between a male's mating status and his assistance at the nest, and inconsistent natural selection against mating with a polygynous male.
Correspondence to: N.T. Wheelwright 相似文献
11.
Frequency and timing of extrapair fertilisation in the polyandrous red phalarope (Phalaropus fulicarius) 总被引:1,自引:0,他引:1
James Dale Robert Montgomerie Denise Michaud Peter Boag 《Behavioral ecology and sociobiology》1999,46(1):50-56
In sequentially polyandrous bird species, where females mate with different males in succession during a single breeding
season, sperm stored by females can occasionally lead to extrapair fertilisations (EPFs) in clutches cared for by the second
and subsequent males. Thus, we predicted that in red phalaropes (Phalaropus fulicarius) – a sex-role-reversed, sequentially polyandrous, arctic breeding shorebird – EPFs would occur more frequently in clutches
laid later in the breeding season. We used multilocus DNA profiling to examine the frequency and timing of EPFs in a population
of red phalaropes breeding in the Canadian high arctic. Using a technique to determine parentage without maternal DNA, we
inferred that 6 of 70 chicks in 18 broods resulted from EPFs – one extrapair chick in each of 6 broods. These results were
supported by a further analysis using microsatellite DNA. As predicted, broods containing EPFs hatched from clutches laid
significantly later in the season than did broods containing no EPFs. The difference in median hatch dates between broods
with and without EPFs was 9.0 days, or 38% of the entire egg-laying period in that season. For the whole breeding season,
we estimated that 6.5% of chicks were sired by extrapair males, which is similar to extrapair paternity estimates for other
sex-role-reversed birds, but relatively low compared to the majority of socially monogamous species studied so far.
Received: 24 August 1998 / Received in revised form: 18 January 1999 / Accepted: 24 January 1999 相似文献
12.
Sex allocation theory predicts that female birds with high-quality mates will benefit from producing more sons, since sons
will inherit their father’s superior traits and enjoy a great reproductive success, whereas females with low-quality mates
will benefit from producing more daughters, since the variance in reproductive success among daughters is typically lower.
The male attractiveness hypothesis may apply to extra-pair paternity (EPP) because socially monogamous females routinely mate
with higher quality males outside the pair bond. We test these predictions using the Tibetan ground tit (Pseudopodoces humilis), a sexually monomorphic, socially monogamous, facultatively cooperative breeder. There was greater variation in actual reproductive
success among males than females due to EPP. An excess of sons was detected for bi-parental (i.e., non-cooperative) broods
wherein EPP was mainly sired by bi-parental males. The pattern was attributed to male-biased sex ratios produced for both
EPP and within-pair offspring within the same broods. The reason for the latter case might be a random allocation of more
offspring to sons by the potentially EPP-exposed females that have an inability to control fertilization by specific males.
In cooperative broods where EPP mostly resulted from within-group helpers of presumed low-quality, as indicated by their failure
in acquiring a social mate, there was a non-significant tendency for EPP offspring to be daughters and for within-pair offspring
in the same broods to be unbiased. These results support the EPP-related male attractiveness hypothesis especially in terms
of the overproduction of sons. Offspring produced through quasi-parasitism was unbiased towards either sex, suggesting a weak
female choiceness with respect to the quality of host males. 相似文献
13.
Parental investment, adult sex ratios, and sexual selection in a socially monogamous seabird 总被引:7,自引:0,他引:7
Although most birds are monogamous, theory predicts that greater female parental investment and female-biased adult sex ratios
will lower the polygyny threshold. This should result in polygynous mating, unless obligate biparental care or the spatial
and temporal distribution of fertilizable females constrains a male’s ability to take advantage of a lowered polygyny threshold.
Here we present data on the extent of male sexually dimorphic plumage, adult sex ratios and breeding season synchrony in three
populations of a socially monogamous seabird, the brown booby Sula leucogaster. For one of these populations, San Pedro Mártir Island, we also present data on differences in male and female parental investment,
mortality and probability of pairing. The extent of plumage dimorphism varied among populations. Sex ratios were female biased in all populations. On San Pedro
Mártir Island, parental investment was female biased, females failed more often than males to find a mate, but there was no
polygyny. We suggest that on San Pedro Mártir: (1) a period of obligate biparental care coupled with a relatively synchronous
breeding season constrained the ability of males to take advantage of a high environmental polygamy potential and (2) the
resulting socially monogamous mating system, in combination with the female-biased adult sex ratio, caused females to be limited
by the availability of males despite their greater parental investment.
Received: 18 November 1999 / Accepted: 24 January 2000 相似文献
14.
Correlates of extra-pair fertilization success in hooded warblers 总被引:13,自引:0,他引:13
Bridget J. M. Stutchbury W. H. Piper D. L. Neudorf S. A. Tarof Judith M. Rhymer G. Fuller R. C. Fleischer 《Behavioral ecology and sociobiology》1997,40(2):119-126
We examined correlates of extra-pair fertilization (EPF) success in the hooded warbler (Wilsonia citrina), a species where females pursue extra-pair matings. The good genes hypothesis predicts that females choose extra-pair mates
with morphological or behavioral traits that reflect differences in male genetic quality. EPFs were common, as 35.3% (42/119)
of broods contained extra-pair young (EPY) and 26.7% (95/356) of nestlings were the result of EPFs. There was a strong skew
in male EPF success which increased the variance in annual male mating success 2–3 fold. However, male morphology did not
predict EPF success, as extra-pair males were not older or larger than the males they cuckolded. Likewise, there were no significant
correlations between the proportion of extra-pair young in a brood and male size or age. The good genes hypothesis predicts
that high-quality males will be consistently preferred as genetic mates, but the number of young sired by a male with his
social mate was not consistent from one year to the next. There was a significant negative correlation between female age
and proportion of EPY produced, which could result if older females obtain higher-quality social mates. We found no strong
evidence that females choose extra-pair mates for good genes, but females may use behavioral rather than morphological cues
to assess relative male quality.
Received: 31 May 1996 / Accepted after revision: 17 October 1996 相似文献
15.
Verena Dietrich-Bischoff Tim Schmoll Wolfgang Winkel Sven Krackow Thomas Lubjuhn 《Behavioral ecology and sociobiology》2006,60(4):563-571
Females of many socially monogamous bird species commonly engage in extra-pair copulations. Assuming that extra-pair males are more attractive than the females’ social partners and that attractiveness has a heritable component, sex allocation theory predicts facultative overproduction of sons among extra-pair offspring (EPO) as sons benefit more than daughters from inheriting their father’s attractiveness traits. Here, we present a large-scale, three-year study on sex ratio variation in a passerine bird, the coal tit (Parus ater). Molecular sexing in combination with paternity analysis revealed no evidence for a male-bias in EPO sex ratios compared to their within-pair maternal half-siblings. Our main conclusion, therefore, is that facultative sex allocation to EPO is absent in the coal tit, in accordance with findings in several other species. Either there is no net selection for a deviation from random sex ratio variation (e.g. because extra-pair mating may serve goals different from striving for ‘attractiveness genes’) or evolutionary constraints preclude the evolution of precise maternal sex ratio adjustment. It is interesting to note that, however, we found broods without EPO as well as broods without mortality to be relatively female-biased compared to broods with EPO and mortality, respectively. We were unable to identify any environmental or parental variable to co-vary with brood sex ratios. There was no significant repeatability of sex ratios in consecutive broods of individual females that would hint at some idiosyncratic maternal sex ratio adjustment. Further research is needed to resolve the biological significance of the correlation between brood sex ratios and extra-pair paternity and mortality incidence, respectively. 相似文献
16.
Altered responses to female odors in parasitized male mice: neuromodulatory mechanisms and relations to female choice 总被引:5,自引:0,他引:5
M. Kavaliers D. D. Colwell K.-P. Ossenkopp T. S. Perrot-Sinal 《Behavioral ecology and sociobiology》1997,40(6):373-384
There is accumulating evidence that females may preferentially select parasite-free or -resistant males. Minimal attention
has, however, been paid to the mate preferences and responses of the parasitized male hosts themselves. Here, we considered
the effects of parasitic infection on male host mate responses, the neuromodulatory correlates of these responses, and the
relations of these responses to female mate choice. Using an odor “preference” test, we examined the effects of different
stages of an acute, sub-clinical infection with the naturally occurring, enteric, single host, protozoan parasite, Eimeria vermiformis, on the responses of male mice, Mus musculus domesticus, to the odors of estrous females along with the responses of uninfected females to the parasitized males. At 4 days post-infection
(non-infective, pre-patent stage) E. vermiformis-infected male mice showed a significantly decreased preference for the odors of estrous females, whereas at 10 days post-infection
(infective, patent stage) infected males showed a significantly increased preference for the odors of estrous females. Parasitized
males displayed no significant changes in their responses to the odors of non-estrous females, supporting effects on the reproductively
related responses of the host. In parallel, estrous females displayed a reduced interest in the odors of infected males. Least
interest was expressed in the odors of the patent, infective males, consistent with the avoidance of contagion. Using selective
opioid peptide receptor agonists and antagonists we found evidence that enhanced kappa opioid peptide (e.g., dynorphin) activity
was related to the decreased sexual interest of the pre-infective males, while augmented delta opioid peptide (e.g., enkephalin)
activity was associated with the enhanced responses of the infective males to females. We further showed that acute kappa
opiate administration reduced the responses of uninfected males to females and that uninfected females displayed modified
responses to the odors of uninfected males subject to acute modifications of opioid activity. We suggest that these differential
shifts in endogenous opioid activity in the parasitized males are associated with and, or related to alterations in neuro-immune
and endocrine functions. These findings show that parasitic infection can have, depending on the stage of infection and associated
neuromodulatory changes, either significant facilitatory or inhibitory effects on male host preferences for and responses
to females.
Received: 22 April 1996 / Accepted after revision: 15 March 1997 相似文献
17.
Jill M. Goldstein Glen E. Woolfenden Jack P. Hailman 《Behavioral ecology and sociobiology》1998,44(1):15-22
Prebreeders of the Florida scrub-jay (Aphelocoma coerulescens) are less likely to be found on their natal territories with a same-sex stepparent than with parents or an opposite-sex stepparent.
We tested two models that had been proposed to account for this sexual asymmetry. The dominance hypothesis states that stepparents
perceive same-sex prebreeders as competitors, primarily for a mate, so behave aggressively toward them. The pair-formation
hypothesis states that prebreeders remain home to pair eventually with the opposite-sex stepparent. Predictions from these
two models were tested by analyses from a quarter-century of records on a study population at Archbold Biological Station
and by new behavioral field observations at the Station. Results clearly rejected the latter and strongly supported the former
hypothesis. No prediction from the pair-formation hypothesis was confirmed: no pairing by a prebreeder of either sex has ever
occurred with a stepparent; remaining home was equally frequent in age-one males with stepmothers and genetic mothers, and
in females with stepfathers and genetic fathers; and the same results were found in age-two prebreeders. By contrast, the
data strongly supported the dominance hypothesis. Field data showed higher aggression rates by stepfathers to male prebreeders
and stepmothers to female prebreeders than by parents to their same-sex genetic offspring. Fewer age-one males remained home
with a stepfather than with the genetic father, and the same was found for age-one females with a stepmother and genetic mother;
at age two, the effect occurred only in female prebreeders. The two hypotheses make different predictions about prebreeders
with two stepparents versus with both parents, thus providing a critical test. The dominance hypothesis correctly predicted
decreased duration at home by age-one males and females; data for age-two females were in the direction of predicted difference
but not significant; and, as in other tests, no effect was found for age-two males. We propose that age-two male prebreeders
remain home despite elevated aggression from stepfathers because these prebreeders retain the possibility of budding from
or inheriting the natal territory.
Received: 16 July 1997 / Accepted after revision: 26 June 1998 相似文献
18.
The extent to which male birds in polygynous species with biparental care assist in nestling feeding often varies considerably
between nests of different mating status. Both how much polygynous males assist and how they divide their effort between nests
may have a profound effect on the evolution of mating systems. In this study we investigated how males in the facultatively
polygynous European starling Sturnus vulgaris invested in their different nests. The amount of male assistance affected the quality of the offspring. Polygynous males
invested as much as monogamous males, but divided their effort asymmetrically between nests, predominantly feeding nestlings
of first-mated (primary) females. Although females partly compensated for loss of male assistance, total feeding frequency
was lower at primary females’ nests than at monogamous females nests. Secondary females received even less assistance with
nestling rearing, and the extent to which males assisted decreased with the length of the interval between the hatching of
the primary and secondary clutches. These results are contrasted with those from a Belgian populations of starlings with a
much more protracted breeding season and thus greater opportunities for males to attract additional mates during the nestling
rearing period. The results show that both the “defence of male parental investment model” and the “asynchronous settlement
model” have explanatory power, but that their validity depends on the potential length of the breeding season.
Received: 21 July 1995/Accepted after revision: 13 July 1996 相似文献
19.
We examined patterns of concurrent multiple mating in a live-bearing poeciliid fish, the sailfin molly (Poecilia latipinna). We tested whether the probability of multiple paternity was related to female body size or fertility and whether the rate
of multiple paternity varied among four populations that differed in their distributions of female body size and fertility.
We analyzed data on mother and offspring genotypes for three polymorphic allozymes by three techniques, including a maximum-likelihood
estimator that accounts for sampling error in both parental and offspring allele frequencies. The estimated rate of multiple
paternity varied between 0.09 and 0.85, and the rate in one population varied seasonally between 0.33 (spring) and 0.85 (autumn).
The variation in these rates was not associated with variation in body-size distributions among populations but was closely
associated with variation in size-specific fertility: populations with greater variation in female fertility had higher multiple-paternity
rates. Within two populations, logistic regression revealed that individual females of larger body size and greater size-specific
fertility were more likely to carry multiply sired broods. This result is consistent with observations made in one of the
populations 5 years earlier. In general, the results strongly suggest that the mating system varies markedly among conspecific
populations of sailfin mollies and that larger, more fertile females are the objects of intermale competition.
Received: 6 May 1996 / Accepted in revised form: 5 December 1996 相似文献
20.
Coalitionary mate guarding by male chimpanzees at Ngogo, Kibale National Park, Uganda 总被引:13,自引:0,他引:13
David P. Watts 《Behavioral ecology and sociobiology》1998,44(1):43-55
Cooperative mate guarding by males is unusual in mammals and birds, largely because fertilizations are non-shareable. Chimpanzees
live in fission-fusion communities that have cores of philopatric males who cooperate in inter-group aggression and in defending
access to the females in their community. Male contest mating competition is restrained within communities, but single high-ranking
males sometimes try to mate guard estrous females. Data from an unusually large chimpanzee commmunity at Ngogo, Kibale National
Park, Uganda, that contains more males than any previously studied community show new variation in chimpanzee mate-guarding
behavior. Contrary to expectation given the large number of males, mate guarding was as common as, or more common than, at
other sites, and males other than the alpha male guarded more often. More strikingly, pairs or trios of top-ranking males
sometimes engaged in cooperative aggression to prevent estrous females from mating with other males, but tolerated each other's
mating activities. Both single males and coalitions mostly guarded periovulatory females. Mate-guarding coalitions were previously
unknown in chimpanzees. Coalitions occurred in large mating parties, seemingly because these often contained too many males
for single males to maintain exclusive access to estrous females. Coalition members gained higher shares of copulations than
they could have expected from solo mate guarding, and suffered lower per capita costs of guarding (as inferred from aggression
rates). Two males who most often participated in coalitions formed two-male coalitions at about the point where the number
of males present made it unlikely that either could get 50% or more of total copulations on his own, and formed trios when
this value dropped below 33%. Kin selection could be a factor in cooperation among male chimpanzees, but coalition members
were not necessarily close relatives and the apparent structure of payoffs fit that of mutualism. Furthermore, reliance of
male chimpanzees on support from allies to maintain high rank could have led to trading of mating exclusivity for support
against mating competitors.
Received: 28 May 1997 / Accepted after revision: 16 May 1998 相似文献