共查询到20条相似文献,搜索用时 31 毫秒
1.
Sharon A. Gill Maarten J. Vonhof Bridget J. M. Stutchbury Eugene S. Morton James S. Quinn 《Behavioral ecology and sociobiology》2005,57(6):557-565
There are few empirical tests of the acoustic mate-guarding hypothesis for the function of duetting in birds. This hypothesis states that when females are fertile, males initiate many songs or answer most of their mates solo songs to form duets and repel rival males seeking extra-pair copulations. We tested the hypothesis by comparing song initiation and answer rates of males and females in socially monogamous buff-breasted wrens (Throthorus leucotis) during pre-fertile and fertile periods. During pre-fertile periods, males often sang for short periods before being answered by their mates, yet first duets were formed earlier relative to dawn and more duets were given during the dawn chorus on pre-fertile than fertile mornings. Males initiated more songs during pre-fertile than fertile periods, whereas there was no difference between stages in female song initiation rates. The proportion of songs answered by individuals of both sexes did not differ between breeding stages. Other mate-guarding behaviours, such as frequent copulation and maintaining close proximity to mates when fertile, did not appear to be important in this species, as no copulations were observed and there was no difference in the time pairs spent in close proximity when females were fertile or not. Parentage analysis revealed that only 3% of 31 broods had young that were likely the result of extra-pair paternity. These findings do not support the acoustic mate-guarding hypothesis, and suggest that the low rate of extra-pair paternity in buff-breasted wrens was maintained without the use of acoustic or traditional paternity guards.Communicated by R. Gibson 相似文献
2.
Ioana Chiver Bridget J. M. Stutchbury Eugene S. Morton 《Behavioral ecology and sociobiology》2008,62(12):1981-1990
Extra-pair fertilizations are common in many socially monogamous species, and paternity studies have indicated that females
may use male vocal performance and plumage ornaments as cues to assess male quality. Female off-territory forays may represent
a key component of female choice and male extra-pair mating success, and female foray behaviour is expected to be strongly
influenced by indictors of male quality. In this study, we examined how male song and ornamentation affect how often females
left their territories, which males they visited and extra-pair paternity in a socially monogamous passerine, the hooded warbler
(Wilsonia citrina). We radiotracked 17 females during the fertile period and quantified male vocal performance (song output and rate) and plumage
characteristics (size of the black melanin hood and colour of the black hood, yellow cheeks and breast areas). We obtained
blood samples and determined paternity at 35 nests including those of 14 females that we radiotracked. Eleven (65%) of the
17 females forayed off-territory, whilst fertile and female foray rate was positively correlated with the number of extra-pair
young in the nest. Females that left their territories more frequently were paired with males that sang at a low rate. In
addition, extra-pair mates had higher song rates than the social mates they cuckolded (5.3 songs/min vs. 4.4 songs/min). Female
off-territory forays or extra-pair paternity were not significantly related to male plumage characteristics. Our results indicate
that a high song rate influences both the foray behaviour of a male’s social mate and the likelihood that he will sire extra-pair
offspring with neighbouring females. 相似文献
3.
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
4.
N. Saino C. R. Primmer H. Ellegren A. P. Møller 《Behavioral ecology and sociobiology》1999,45(3-4):211-218
The barn swallow (Hirundo rustica) is a socially monogamous passerine which usually breeds in colonies where extra-pair copulations are frequent. Males intensively
guard their mates during the female fertile period. Since males are more likely to be available for extra-pair copulations
when their mate is not fertile, synchrony in timing of breeding may affect paternity of individual males. In this study, we
analysed the change in mate-guarding rate by males in relation to the fertility condition of the female, and the relationships
between breeding synchrony and density with paternity in first broods of 52 male barn swallows. Paternity (proportion of nestlings
fathered in own brood) was assessed by typing of three highly polymorphic microsatellite loci. Mate guarding by males peaked
during the fertile period of their mates. Paternity increased as breeding synchrony in the colony increased. Paternity of
barn swallows is positively associated with the degree of exaggeration of male tail ornaments. The relationship between male
ornamentation and paternity was partly mediated by an effect of ornament size on breeding synchrony. We suggest that females
might delay breeding with low-quality males to enhance their opportunities for being fertilised by high-quality extra-pair
males.
Received: 16 January 1998 / Accepted after revision: 25 October 1998 相似文献
5.
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
6.
Russell C. Titus C. Ray Chandler Ellen D. Ketterson Val Nolan Jr. 《Behavioral ecology and sociobiology》1997,41(3):165-169
Frequency of singing by birds may vary with reproductive stage in ways that reflect variation in the functions of song in
intersexual and intrasexual communication. In dark-eyed juncos (Junco hyemalis) high-amplitude song is produced only by males. To investigate the function of this song, we tested whether fertility of
females affected singing by their mates or by neighboring males. Using focal observations, song censuses, and radiotracking
data, we determined whether song production varied between and among periods when females were fertile and non-fertile. Our
findings show that males do not increase song production when their mates are fertile, nor do they increase song production
when neighboring females are fertile. These results suggest that male juncos do not signal their intent to defend territories
(or mates) more when females are fertile and that they do not use song to advertise to specific potential participants in
extra-pair fertilizations.
Received: 13 February 1997 / Accepted after revison: 2 May 1997 相似文献
7.
Female control of offspring paternity in a western population of red-winged blackbirds (Agelaius phoeniceus) 总被引:9,自引:0,他引:9
E. M. Gray 《Behavioral ecology and sociobiology》1996,38(4):267-278
Extra-pair copulations, which occur when individuals that have formed social relationships to breed copulate outside their
pairbond, now are recognized as an important component of reproductive success in many species. In situations where both males
and females benefit from extra-pair copulations without incurring much risk, an inevitable conflict arises between pairbonded
mates. In this study I investigated the conflict of interest between male and female reproductive strategies in a western
population of red-winged blackbirds (Agelaius phoeniceus). Female red wings in this population initiate extra-pair copulations, which resulted in a 35% rate of extra-pair fertilization.
Females initiated the majority (78%) of extra-pair copulations away from their nesting territory where pairbonded individuals
typically copulate, and females that engaged in extra-pair copulations spent a significantly greater amount of time off the
marsh during peak fertilization compared to females that did not. In addition, females that nested in areas with a large number
of potential extra-pair partners produced significantly more extra-pair fertilized young compared to females that nested on
marshes with few male neighbors. Males’ strategies to protect paternity were limited primarily to patrolling territory boundaries
and to opportunistically preventing extra-pair copulations off the marsh when they were visible. In this population females
appear to use behavioral means to control nestling paternity, which in turn directly affected their mate’s reproductive success,
and males were restricted to using strategies that were largely ineffective at preventing the threat of extra-pair paternity.
Received: 23 December 1994/Accepted after revision: 17 December 1995 相似文献
8.
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
9.
Non-aggressive mate guarding by the blue-footed booby: a balance of female and male control 总被引:3,自引:1,他引:2
Thirteen pairs of blue-footed boobies (Sula nebouxii) were observed on their colony. Pairs courted frequently and, on average, copulated 24 times during the 30 days before laying,
with 38% of those copulations occurring in the last 5 days (presumed fertile period). Males and females increased attendance
at the nest site as laying approached. Seven females performed an average seven extra-pair copulations, with 1–2 paired male
neighbors, but these were less concentrated in the presumed fertile period than within-pair copulations, and the last two
copulations of all 7 females were with their social mates. Rates of female extra-pair copulations were six times lower when
their social mate was present, and during the presumed fertile period, no female performed an extra-pair copulation in the
presence of her mate. Males did not respond to infidelity of social mates with aggression, prompt copulation, retaliatory
copulation, or increase in copulation. Seven of 13 males performed an average of five extra-pair copulations, with 1–3 paired
female neighbors, before their own mates began egg-laying. The males' extra-pair copulations represented only 4% of their
total copulations during their own mates' presumed fertile periods. Females, the larger sex, apparently control sexual access
and copulate with extra males to achieve extra-pair fertilization. Males pursue a mixed strategy: they copulate with extra
females, mostly outside their own mate's presumed fertile period, and they copulate increasingly with their social mate as
laying approaches, probably assuring some paternity by mate guarding, involving attendance and courtship. Behavior of males
and females is also consistent with other hypotheses for extensive joint nest site attendance: pairbonding, copulation access,
and territory acquisition.
Received: 14 November 1997 / Accepted after revision: 16 May 1998 相似文献
10.
Seasonal variation in animal signalling behaviour has been well documented and has contributed much to our understanding of
male signals. In contrast, we know little about seasonal variation in female signals or signals produced jointly by males
and females, such as the vocal duets of birds. Here, we examine how singing behaviour changes in relation to time of year
and breeding stage in rufous-and-white wrens (Thryothorus rufalbus), neotropical songbirds where both males and females sing and where breeding partners coordinate songs to produce vocal duets.
We recorded a colour-marked population of birds over an extended time period encompassing multiple breeding stages. Across
all time frames and breeding stages, males sang at higher rates than females and male solos were more common than duets or
female solos. Males and females showed divergent seasonal patterns of singing. Females sang more often early in the year,
during the pre-breeding season, and female song tapered off as the breeding season progressed. Duetting followed a parallel
pattern, which resulted from females showing less duet responsiveness to their partner’s songs later in the year. Male independent
song rate peaked at the onset of the rainy season – a time when females become fertile – and males showed the highest level
of duet responsiveness during this period. Our results suggest that early in the year, duets appear to be cooperative displays,
functioning in joint territory defence and/or the coordination of breeding activities. When females are fertile, however,
increased duet responsiveness by males is consistent with mate or paternity guarding. 相似文献
11.
The high frequency of extra-pair paternity in tree swallows is not an artifact of nestboxes 总被引:6,自引:0,他引:6
C. A. Barber Raleigh J. Robertson Peter T. Boag 《Behavioral ecology and sociobiology》1996,38(6):425-430
A common criticism of nestbox studies is one of creating artificial nesting conditions and breeding behavior different from
what would be seen under natural conditions. We assessed the frequency of extra-pair paternity (percentage of broods with
at least one extra-pair young) in 25 families of tree swallows (Tachycineta bicolor) nesting in natural cavities and compared it to that in a nestbox population. We found that 84% of females nesting in natural
cavities obtained fertilizations from extra-pair males. These extra-pair males fathered 69% of all nestlings. Studies of tree
swallows breeding in nestboxes have shown that 50–87% of broods contained extra-pair young, with extra-pair males fathering
38–53% of all the young. In broods with extra-pair paternity, natural cavities contained a significantly greater proportion
of extra-pair young than did nestboxes. Despite differences in nesting habitat and female age structure, the frequency of
extra-pair paternity did not differ significantly between the natural-cavity and nestbox populations. Therefore, the presence
of extra-pair paternity in tree swallows is not an artifact of nestboxes or of artificial nesting conditions.
Received: 2 May 1995/Accepted after revision: 14 January 1996 相似文献
12.
Davina L. Hill Jan Lindström Ruedi G. Nager 《Behavioral ecology and sociobiology》2011,65(11):2049-2059
Whether parental effort can be negotiated between partners over ecological time and adjusted across different contexts is
not well understood. We manipulated male extra-pair copulation (EPC) opportunity in captive zebra finches, Taeniopygia guttata, to test whether males adjust incubation effort to the mating context and to examine how females respond to their partner’s
effort. Birds without previous breeding experience were paired randomly and bred with the same partner twice. In the first
breeding attempt, half the males received EPC opportunities with ‘extra-pair females’ during incubation, while the other half
did not. Males that received EPC opportunities in the first breeding attempt did not in the second breeding attempt and vice
versa. We recorded incubation effort on days when EPC opportunities were not presented. In their first breeding attempt, males
with EPC opportunities incubated less than those without. Females compensated fully for the deficit in male care so that a
pair’s combined incubation effort was unchanged. In the second attempt, when a male’s opportunity for EPCs was switched, individuals
showed the same level of incubation effort that they had previously, irrespective of the current availability of extra-pair
females. This suggests that division of effort was negotiated in the first breeding attempt and maintained without significant
adjustments in the second attempt. The effects of male EPC opportunity in the first breeding attempt on subsequent incubation
effort suggests that individual parental decisions can be shaped by previous experience and this may partly explain conflicting
results in studies where individuals’ histories were not known. 相似文献
13.
Susan L. Balenger L. Scott Johnson Brian S. Masters 《Behavioral ecology and sociobiology》2009,63(3):403-411
Ornamental traits are thought to evolve because they give individuals an advantage in securing multiple mates. Thus, the presence
of ornamentation among males in many monogamous bird species presents something of a conundrum. Under certain conditions,
extra-pair paternity can increase the variance in reproductive success among males, thus increasing the potential for sexual
selection to act. We addressed this possibility in the mountain bluebird (Sialia currucoides), a socially monogamous songbird in which males possess brilliant ultraviolet (UV)-blue plumage. Specifically, we asked whether
a male’s success at siring offspring within his own nest and within the nests of other males was related to his coloration.
In pairwise comparisons, males that sired extra-pair offspring were not more colorful than the males that they cuckolded.
However, males that sired at least one extra-pair offspring were, on average, brighter and more UV-blue than males that did
not sire extra-pair offspring. Brighter, more UV-blue males sired more offspring both with their own mate and tended to sire
more offspring with extra-pair mates and thus sired more offspring overall. Our results support the hypothesis that the brilliant
UV-blue ornamental plumage of male mountain bluebirds evolved at least in part because it provides males with an advantage
in fertilizing the eggs of multiple females. 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.
Females of socially monogamous species may copulate with attractive non-mates to obtain access to the genes of such males,
and a preference for attractive copulation partners may result in sexual selection. Extra-pair copulations are common in the
socially monogamous barn swallow Hirundorustica, and a 2-year study of paternity using multi-locus DNA fingerprinting demonstrated that 33% of 63 broods and 28% of 261 offspring
were sired by extra-pair males. The frequency of extra-pair offspring within broods was highly skewed with the majority of
all broods having either no extra-pair offspring or only extra-pair offspring. Individual pairs were consistent in their frequency
of extra-pair paternity among broods, and the repeatability of extra-pair paternity of multiple broods of the same female
was statistically significant. The proportion of extra-pair offspring was negatively related to the tail length of the male
attending the nest. Behavioural observations showed that extra-pair fertilizations were more likely in broods raised by females
that had been observed to engage in extra-pair copulations. The frequency of extra-pair offspring was unrelated to the intensity
of two male paternity guards, mate guarding and the rate of intra-pair copulations. In an analysis of extra-pair paternity
and male parental care in different broods of the same male, male barn swallows fed their offspring relatively less frequently
if the brood contained more extra-pair offspring. Therefore, female barn swallows pursue extra-pair copulations with attractive
males, which may result in sexual selection, even though extra-pair paternity is costly for females due to the reduction of
paternal care by their social mates.
Received: 24 January 1997 / Accepted after revision: 2 August 1997 相似文献
16.
Anders Pape Møller 《Behavioral ecology and sociobiology》1990,27(1):23-29
Summary Badge size, which functions as a signal of dominance status in male house sparrows Passer domesticus, was significantly related to their sexual behavior. Males with large badges participated in communal displays (multi-male chases directed towards single females) more often than males with small badges, irrespective of whether the female involved was the male's mate or not. Experimentally released females were more often chased if they were fertile than if they were nonfertile. Estradiol-implanted females were chased more often than control females without a hormone implant, and males with large badges chased estradiol-implanted females more often than did males with small badges. Both forced extra-pair copulations during communal displays and unforced extra-pair copulations were more often achieved by males with large than small badges. Male house sparrows with large badges also copulated with their mates at a higher rate than did males with small badges. A higher certainty of paternity therefore is hypothetized to accrue to male house sparrows with large badges. 相似文献
17.
Certainty of paternity covaries with paternal care in birds 总被引:5,自引:0,他引:5
Summary Male investment in parental care has been hypothesized to be affected or not to be affected by their certainty of paternity, depending on the particular assumptions of theoretical models. We used data on paternal care and extra-pair paternity from 52 bird species to determine whether male parental care was related to certainity of paternity. Paternal care was measured as the relative male contribution to nest building, courtship feeding, incubation, and feeding of nestlings, respectively. Males of avian taxa did not provide less parental care during nest building, courtship feeding and incubation if the frequency of extra-pair paternity was high. However, male participation in feeding of offspring was significantly negatively related to the frequency of extra-pair paternity. This was also the case when the effects of potentially confounding variables such as developmental mode of offspring (which may result in males being freed from parental duties), extent of polygyny (which may result in less paternal care), and the frequency of multiple clutches during one breeding season (which may increase the probability of finding fertile females during the nestling period) were controlled statistically. These results suggest that the extent of paternal care has been affected by certainty of paternity, and that sex roles during the energetically most expensive parts of reproduction have been shaped by sperm competition. 相似文献
18.
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
19.
Elisabeth Bolund Holger Schielzeth Wolfgang Forstmeier 《Behavioral ecology and sociobiology》2012,66(6):975-984
Song is used as a signal in sexual selection in a wide range of taxa. In birds, males of many species continue to sing after pair formation. It has been suggested that a high song output after pair formation might serve to attract extra-pair females and to minimise their own partner’s interest in extra-pair copulations. A non-exclusive alternative function that has received only scant attention is that the amount of song might stimulate the own female’s investment into eggs in a quantitative way. We address these hypotheses in a captive population of zebra finches, Taeniopygia guttata, by relating male undirected song output (i.e. non-courtship song) to male egg siring success and female reproductive investment in two different set-ups. When allowed to breed in aviaries, males with the highest song output were no more attractive than others to females in an analysis of 4,294 extra-pair courtships involving 164 different males, and they also did not sire more offspring (both trends were against the expectation). When breeding in cages with two different partners subsequently, females produced larger eggs with more orange yolks when paired to a male with a high song output. These findings suggest that singing activity in paired zebra finch males might primarily function to stimulate the partner and not to attract extra-pair females. 相似文献
20.
David F. Westneat Anne B. Clark Katherine C. Rambo D. F. Westneat 《Behavioral ecology and sociobiology》1995,37(5):349-356
We video-taped male and female red-winged blackbirds (Agelaius phoeniceus) feeding individual chicks in order to test the hypothesis that food might be differently allocated to within-pair offspring and extra-pair young. We found no evidence that paternity influenced the allocation of food by either males or females. Both males and females fed male offspring significantly more, but there was no tendency for paternity to be skewed by gender. Females fed older offspring significantly more, whereas males did not; extra-pair fertilizations, however, were not associated with lay or hatch order of the chicks. Given that males do not appear to discriminate within-pair from extra-pair offspring directly, these results are consistent with current theory on the effect of paternity on paternal behavior. We discuss briefly some of the possible reasons why discrimination might be lacking in red-winged blackbirds and in other species in which the possibility of discrimination of paternity and allocation of paternal behavior has been studied. 相似文献