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1.
Sperm competition and the level of polyandry in a bushcricket with large nuptial gifts 总被引:4,自引:0,他引:4
Variation in paternity due to sperm competition or post-copulatory female choice has a major influence on animal mating system evolution and on the levels of genetic variability in natural populations. However, there are relatively few studies comparing the outcome of sperm-competition experiments in the laboratory with natural variation in polyandry among families from the field. In the bushcricket Ephippiger ephippiger, females mate multiply, and the males provide them with a large, nutritious, and probably expensive, donation at mating. We examined paternity in a series of laboratory matings, where females mated with two males, and amongst a series of families collected from a natural population. In the laboratory, paternity was highly bimodally distributed: 24% of families had offspring fathered by the first male to mate, 68% by the second male (in only 8% was paternity shared). In the field, paternity was more mixed: only 27% of families had a single father, 14% had more than two fathers, whilst 59% had two fathers. While unsuccessful matings may contribute to the highly biased paternity in the laboratory, they cannot fully explain the high incidence of complete P2 families. Nonrandom sperm utilisation is therefore likely. Greater sperm mixing in the field probably results from females mating with more males, but the distribution of paternity also reflects an active process of nonrandom sperm utilisation. Confidence of paternity due to last male advantage may be relatively high in this species, and therefore may have facilitated the evolution of the large spermatophore in E. ephippiger.Communicated by D. Gwynne 相似文献
2.
A comprehensive understanding of sexual selection requires knowledge of the traits and mechanisms responsible for increasing a male’s paternity share (proportion of progeny sired) relative to that of other males mating with the same female. In this study we manipulated by starvation the expression of traits that might influence male paternity share in Tribolium castaneum. We then conducted experiments to examine how male starvation affects male performance during sequential episodes of sexual selection from mating to progeny production, and investigated female control over specific stages by using live vs dead females. Comparison of starved vs fed males revealed that T. castaneum females have control over spermatophore transfer during mating, as live females rejected inseminations by starved (“low quality”) males. None of the measured male copulatory behaviors (leg-rubbing frequency, asymmetry, and percent of time spent rubbing) affected the probability of successful insemination, but the last two were positively associated with male paternity share. Spermatophore positioning within the female reproductive tract was not affected by male treatment (starved/fed), by female treatment (live/dead), or by male copulatory behaviors. Starvation, however, had a dramatic effect on male reproductive physiology, decreasing both accessory gland size and total number of sperms transferred (but not sperm viability in seminal vesicles). In addition, females who mated to starved males stored fewer sperms in their spermathecae, which, together with decreased ejaculate size, may explain the reduced paternity share of starved males compared to fed males. This study elucidates some cryptic mechanisms influencing male reproductive success and aids our understanding of trait evolution through sexual selection. 相似文献
3.
Sjouke A. Kingma Michelle L. Hall Anne Peters 《Behavioral ecology and sociobiology》2012,66(8):1115-1123
In passerine birds, storage and maturation of sperm takes place in the cloacal protuberance (CP), an external swelling of the reproductive organ. The considerable variation in CP size among species is presumed to be a consequence of varying levels of sperm-competition, but whether individual variation in CP size within a species also reflects sperm competition is not well established. Here, we study temporal variation in male CP size in relation to within-pair and extra-pair mating opportunities and cuckoldry risk in purple-crowned fairy-wrens Malurus coronatus. This is a socially monogamous cooperatively breeding passerine that can breed year-round and has low levels of extra-pair paternity (in 6?% of broods). We show that male CP size sharply increased a few weeks before, and rapidly regressed after his partner laid eggs, consistent with a cost of its maintenance and/or sperm production. Surprisingly, despite low levels of extra-pair paternity, CP size of non-breeding and pre-breeding males was positively correlated with the number of breeding females in the population, suggesting that CP size is sensitive to extra-pair mating opportunities. However, CP sizes do not seem to reflect cuckoldry risk: CP size of dominant males was unaffected by the presence of a subordinate that was unrelated to the dominant female, although those subordinates occasionally sire offspring, and had a larger CP than subordinates living with their mother. Our results suggest that, even in a species with low levels of extra-pair paternity, individual investment in sperm storage reflects both within-pair and, albeit to lesser extent, extra-pair mating opportunities. 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.
Socially monogamous partners suffer conflicting interests concerning various aspects of reproduction such as parental care, copulation and fertilization. Female black-legged kittiwakes commonly eject their mates' sperm immediately following copulations. Because sperm ejection reduces male sperm competitiveness and paternity assurance, males and females have conflicting interests as regards sperm ejection. Males whose mates ejected their sperm at least once remained longer on their mates' backs after the last insemination which apparently prevented the females from ejecting sperm. These results suggest that compelling females to retain their sperm may be a previously unidentified tactic employed by males to assure their paternity. Females tried to prevent their mates from witnessing sperm ejection by ejecting sperm after their mates departed from the nest. Females were more likely to eject sperm when they terminated the copulations by unbalancing the male. The conflict over sperm ejection was related to the ability of the females to end the copulations which covaried with the body mass of their mates. These findings suggest that conflicts in monogamous pairs also exist over the disposition of sperm.Communicated by C.R. Brown 相似文献
6.
Oddmund Kleven Frode Jacobsen Rasa Izadnegahdar Raleigh J. Robertson Jan T. Lifjeld 《Behavioral ecology and sociobiology》2006,59(3):412-418
In socially monogamous species, extra-pair paternity has the potential to increase the variance in male reproductive success,
thereby affecting the opportunity for sexual selection on male extravagant ornamentation. In the European barn swallow (Hirundo rustica rustica), the tail streamer length is a sexually selected male ornament and an honest indicator of viability. The North American
barn swallow (Hirundo rustica erythrogaster) also shows sexual dimorphism in tail streamer length, but whether this trait holds the same signalling function in this
subspecies is a controversial issue, and the available literature is presently scarce. Here, we present data on paternity
in the North American barn swallow, including a complete sampling of extra-pair sires in four colonies. We analysed how extra-pair
paternity affected the variance in male fertilization success and examined whether male tail streamer (i.e. the outermost
tail feather) length correlated with fertilization success (n=86 males). Extra-pair paternity constituted 31% of all offspring and significantly increased the variance in male fertilization
success. The number of offspring sired by extra-pair males accounted for almost half of the total variance in male fertilization
success. Males with naturally long tail streamers had a higher fertilization success than males with shorter tail streamers,
and this pattern was mainly caused by a higher extra-pair success for males with long tail streamers. Males with long tail
streamers also paired with early breeding females in prime body condition. These results are consistent with the idea that
there is directional sexual selection on male tail streamer length, possibly mediated through male extra-pair mating success
or the timing of breeding onset. 相似文献
7.
Mario E. Favila Janet Nolasco Ivette Chamorro Florescano Miguel Equihua 《Behavioral ecology and sociobiology》2005,59(1):38-43
Field observation and laboratory experiments were conducted to investigate sperm competition and patterns of sperm fertilization under different experimental conditions in the carrion ball-roller beetle Canthon cyanellus cyanellus. Males in nature can mate with females whose spermathecae contains fertile sperm from other males. Sperm precedence was investigated using a visible genetic marker. The progeny of red (homozygous recessive) virgin females mated once with a red male and afterward, once with a green beetle (homozygous dominant) and vice versa, revealed that regardless of its color, the last male to mate fertilized c.a. 50% of the eggs, suggesting strong sperm competition. Males were able to achieve higher levels of paternity (more than 80%) when mated ad libitum with previously mated females, although large amount of variance in paternity does not exclude the possibility of first male sperm precedence or female cryptic choice. These results suggest that repeated mating and sperm replacement are the mechanisms by which last males achieve sperm precedence. 相似文献
8.
Paolo Galeotti Fabio Pupin Diego Rubolini Roberto Sacchi Pietro A. Nardi Mauro Fasola 《Behavioral ecology and sociobiology》2007,61(5):711-718
Sperm competition models predict that males should adjust their sperm expenditure according to the risk and/or intensity of
sperm competition. In this paper, we analysed copulatory behaviour of both sexes and sperm expenditure in relation to female
mating status (virgin or mated) in the freshwater crayfish Austropotamobius italicus, a species where males have been reported to feed on and remove sperm laid by other males. The same females were allowed
to be inseminated sequentially by two males, and we compared the sexual behaviours of partners between the first (virgin females)
and the second mating (mated females). We found that female resistance did not differ between the first and the second mating,
nor males refused or took more time to mount a mated female. However, when mating with a mated female, males reached an effective
copulation position significantly later. This occurred because second-mating males removed, by eating, all or most spermatophores
previously deposited by first males. As removal was often incomplete, this resulted in a larger amount of sperm being deposited
on female ventral parts after the second mating, although second males did not allocate more sperm to mated females than first
males did. Thus, the peculiar mode of sperm competition, where males remove previously deposited sperm, and the consequent
predictable strong last male prevalence in paternity likely led to the observed lack of adjustment of sperm expenditure to
female mating status in this species. 相似文献
9.
Ben C. Sheldon Pete Davidson Gabriella Lindgren 《Behavioral ecology and sociobiology》1999,46(3):141-148
There is increasing evidence that sexual selection may be intense even in socially monogamous birds, resulting from both
mate choice and sperm competition. We studied these two modes of sexual selection experimentally by removing paired male collared
flycatchers, Ficedula albicollis, from their mates for 2 days and investigating the factors that influenced the likelihood of a replacement male appearing
and how the removals influenced paternity. Replacement males (usually neighbouring males) appeared at 81% (n = 37) of nests where males were removed. The likelihood of this appearance was unaffected by the probable reproductive value
of the female's clutch to the replacing male. A replacement was, however, less likely when the original male had a large forehead
patch, a trait previously shown to be subject to sexual selection in this population. Experimental removal of males increased
the level of sperm competition: 74% of experimental broods were multiply sired, compared to 29% of unmanipulated broods in
a previous study. Only two factors predicted how paternity was shared between males: removed males fathered more young if
removed closer to laying, and if they had larger forehead patches. The former result is consistent with last-male sperm precedence
determining paternity, whereas the latter adds to other evidence that forehead patch size is the target of female preference
in this species. Our results suggest that females exert some control over male replacement, and also that they may influence
the fertilisation success of males by behavioural means.
Received: 15 July 1998 / Received in revised form: 16 March 1999 / Accepted: 28 March 1999 相似文献
10.
Christopher R. Friesen Amelia R. Kerns Robert T. Mason 《Behavioral ecology and sociobiology》2014,68(9):1419-1430
In some species, sperm is stored within the female reproductive tract for months to years, and yet remains viable to fertilize eggs and produce offspring. Female red-sided garter snakes store sperm for over 7 months of winter dormancy. In previous work, we demonstrated that these stored sperm account for an average of 25 % paternity of a litter when the female mates with a male at spring emergence. Here, we tested whether last-male sperm precedence was prevalent when a female mates with two males during the spring. On average, paternity was shared equally among the first (P1 proportion of paternity of the first male to mate) and second males (P2) to mate in the spring, and stored sperm (Pss), but the variance in paternity was high. Thus, last male sperm precedence may diminish when a female has more than two mates. Male size did not affect paternity, but, as the interval between matings increased, P1 increased at the expense of Pss. Interestingly, as the second spring male’s copulation duration increased, P1 also increased at the expense of P2. This result suggests that female influence over sperm and/or copulatory plug transfer during matings may also affect which male fathers her offspring in response to coercive matings as we assisted females to mate for their second mating. Finally, all females were spring “virgins”; consequently, sperm stored from autumn matings (and/or previous spring matings) remain competitive even when faced with two rivals in sperm competition and is likely the driver of the evolution of sperm longevity. 相似文献
11.
Determinants of paternity success in the spider Pholcus phalangioides (Pholcidae: Araneae): the role of male and female mating behaviour 总被引:1,自引:0,他引:1
In double mating experiments, we examined whether and to what extent various male and female behavioural traits influence
the course of mating and fertilization success in the cellar spider. In males, we focussed on pre-copulatory behaviour and
on the rhythmic twisting movements that the male performs with his pedipalps during copulation. In females, we investigated
remating decisions and the effect of female termination of copulation. Second males fertilized a high proportion of the eggs
(P
2: median 89%) despite much shorter second matings, with high variation in relative paternity success. The number of pedipalp
movements (PPMs) of either male was a better predictor of paternity than copulation duration. Our results suggest that in
second matings, PPMs help to remove sperm from previous males, whereas in first matings a high number of PPMs enhances fertilization
success, either due to numerical sperm competition or cryptic female choice. Furthermore, we found a negative male age effect
on paternity in second matings, implying that age-related deterioration of spermatozoa may promote variation in fertilization
success. Female receptivity decreased significantly in second matings; only 70% of the females remated. Females that accepted
a second copulation were found to terminate these much earlier and with higher probability than first matings. This suggests
that the intensity of conflict between the sexes is higher in second matings. Increased intensity of sexual conflict may be
responsible for stronger selection on male traits, as pre-copulatory behaviour and age only affected male copulatory performance
and paternity in second matings.
Electronic Publication 相似文献
12.
Michelle Pellissier Scott 《Behavioral ecology and sociobiology》1990,26(1):31-39
Summary Parental behavior that has an impact on the increased survival of offspring, an important factor in the evolution of parental care, can include both guarding and provisioning. The effects of these two components of parental care can be separated and quantified in the burying beetle Nicrophorus orbicollis in which both male and female cooperate to rear young. Although in the absence of competition, reproductive success is reduced by the presence of the second parent in the brood chamber, two parents dramatically reduce the probability that conspecifics will usurp the resource, replace either the male or female, kill the newly hatched brood, and produce a replacement clutch. After the establishment of the burial chamber (but not before) beetles appear to assist their mates in driving off intrasexual competitors. Male assistance in burial does not account for very much of the variance in the speed in which the carcass can be concealed nor are two parents essential to guard against insect predators. There were no significant differences in the duration of parental care by males paired with virgin and non-virgin females suggesting that paternity of the brood for which the male provides care is not a factor determining the length of care. Since male and female reproductive success is limited in Nicrophorus by access to suitable carcasses, many of the typical asymmetries in the costs and benefits of parental care are lacking. However since sperm displacement is not complete, paternity of the replacement clutch, for which the male does not provide care, may be a factor encouraging male desertion before female desertion. Other factors important in the evolution of paternal care, especially the probability of additional reproductive opportunities, are discussed. 相似文献
13.
Kaspar Delhey Anne Peters Arild Johnsen Bart Kempenaers 《Behavioral ecology and sociobiology》2007,61(6):853-862
Sex-allocation theory predicts that females paired to attractive males should bias the brood sex ratio towards male offspring,
as these would inherit the attractiveness of their father. We studied sex allocation based on male ornamentation in blue tits.
Brood sex ratios varied with male UV coloration in an age-dependent manner. For juvenile males, the proportion of sons increased
with increasing UV ornamentation, which is in agreement with previous findings from a Swedish population. However, the relationship
between UV ornamentation and brood sex ratio was reversed for adult males, with females paired to less UV-ornamented adult
males producing more sons. This pattern fits with the observation that, in our population, less UV-ornamented adult males
sire the majority of extra-pair young. To test the causality of the association between brood sex ratio and male coloration,
we experimentally manipulated crown colour largely within the natural range. We created two groups of males: one with higher
and one with lower UV reflectance, UV(+) and UV(−), respectively. Contrary to our expectations, there was no significant treatment
effect. However, in UV(−), but not UV(+) males, the proportion of sons was negatively correlated with male coloration before
manipulation. This suggests that the UV(−) treatment caused males that were more UV ornamented to decline more in attractiveness,
as shown in a similar experiment in Sweden. However, given that correlational patterns differ between these populations, similarities
in experimental results should not be taken as evidence for consistent patterns of adaptive sex allocation in this species. 相似文献
14.
Male–male competition has historically been considered the major force driving sexual selection. However, female choice and inter-sexual conflict are increasingly recognized as important influences affecting differential mating and reproductive success. Many females exhibit preferences for particular males; however, male strategies may conflict with females’ ability to obtain their mate preferences. To influence paternity, females must affect both (1) whether or not sexual interactions occur, particularly during the periovulatory period (POP) and (2) the outcome of sexual interactions. This study focuses on the effectiveness of female choice in wild chimpanzees (Pan troglodytes verus). Over 2,600 h of data were collected on two habituated chimpanzee communities in the Taï National Park, Côte d’Ivoire. Female mate preferences were measured by quantifying proceptive and resistance behavior toward males in both the periovulatory period and non-POP phases of estrus. The efficacy of female preference was measured both (1) by measuring success rates of female proceptivity and resistance behaviors and (2) by determining how well measures of female mate preference (proceptivity and resistance rates) predict male mating success. Though male chimpanzees are clearly dominant to females, the results indicate that females could effectively resist male solicitations and, in most cases, unwanted copulations were averted. Both female proceptivity and resistance rates correlate (positively and inversely, respectively) with male mating success in POP. Outside POP, female proceptivity rates corresponded with male mating success, but resistance rates did not. Males (irrespective of rank) that were preferred by females obtained higher mating success compared to other males during the POP, suggesting that females were effective in their mate choice and that, despite clear male dominance, female choice influences paternity in wild chimpanzees. 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.
Sperm competition or sperm selection: no evidence for female influence over paternity in yellow dung flies Scatophaga stercoraria 总被引:2,自引:0,他引:2
L. W. Simmons P. Stockley R. L. Jackson G. A. Parker 《Behavioral ecology and sociobiology》1996,38(3):199-206
Recent studies of non-random paternity have suggested that sperm selection by females may influence male fertilization success.
Here we argue that the problems originally encountered in partitioning variation in non-random mating between male competition
and female choice are even more pertinent to interpreting patterns of non-random paternity because of intense sperm competition
between males. We describe an experiment with the yellow dung fly, Scatophaga stercoraria, designed to partition variance in the proportion of offspring sired by the second male, P
2, between males and females, and to control for sperm competition. Large males were shown to have a higher P
2 than small males but P
2 was independent of the size of the female’s first mate. This result might suggest an absolute female preference for large
males via sperm selection. However, large males have a higher constant rate of sperm transfer and displacement. After controlling
for this effect of sperm competition, large males did not achieve higher paternity than small males. We argue that a knowledge
of the mechanism of sperm competition is essential so that male effects can be controlled before conclusions are made regarding
the influence of sperm selection by females in generating non-random paternity.
Received: 4 April 1995 / Accepted after revision: 17 October 1995 相似文献
17.
James V. Briskie Robert Montgomerie Tarmo Põldmaa Peter T. Boag 《Behavioral ecology and sociobiology》1998,43(3):181-190
In species where females copulate with more than one male during a single breeding attempt, males risk investing in offspring
that are not their own. In the polygynandrous Smith's longspur (Calcarius pictus), females copulate sequentially with one to three males for each clutch of eggs and most of these males later assist in feeding
the young. Using multilocus DNA profiling, we determined that there was mixed paternity in >75% of broods (n=31) but that few offspring (<1% of 114 nestlings) were sired by males outside the polygynandrous group. Male feeding rate
increased significantly with the number of young sired, with males siring four nestlings feeding the brood at double the frequency
of males siring only a single nestling. However, male Smith's longspurs appear to show a graded adjustment of paternal care
in response to paternity only when other males are available to compensate for reduced care: feeding rate did not vary in
relation to paternity when only one male provisioned young at the nest. There was no evidence that males could recognise their
own offspring within a brood and feed them preferentially. The number of offspring sired by each male was significantly correlated
with the number of days spent copulating with the attending female: on average, a male sired one offspring for every 2 days
of copulatory access. If males use their access to females to estimate paternity (and thereby decide on their subsequent level
of parental investment), a positive relationship is expected between the amount of female access and the subsequent feeding
rate to the nestlings. Nonetheless, male feeding effort was only weakly correlated with female access and more study is needed
to determine how males estimate their paternity in a brood.
Received: 1 June 1997 / Accepted after revision: 1 April 1998 相似文献
18.
Chiara Boschetto Clelia Gasparini Andrea Pilastro 《Behavioral ecology and sociobiology》2011,65(4):813-821
While both sperm number and quality are now recognized to be important in determining the outcome of sperm competition, very
few studies have experimentally assessed the influence of these two parameters simultaneously. We studied the effect of sperm
quality and number on competitive fertilization success in an internal-fertilizing fish, the guppy (Poecilia reticulata), which is characterized by high levels of sperm competition. We artificially inseminated virgin females with varying proportion
of sperm from two competing males, while holding constant the total number of sperm transferred to the female. Sperm morphology
and sperm swimming velocity were also determined prior to insemination. The paternity outcome of sperm competition trials
was assessed through molecular analyses of the resulting offspring using polymorphic microsatellite loci. We found that both
sperm number and sperm velocity affected the outcome of sperm competition, with males that contributed more and faster sperm
achieving a greater paternity share. 相似文献
19.
Peter Frederick 《Behavioral ecology and sociobiology》1987,21(4):223-228
Summary I intensively observed the mating behavior of 134 pairs of white ibises for over 15 000 pair hours to examine the responses of males to extrapair copulations (EPC) involving their mates. Females often cooperated completely in apparently fertile EPCs. Male mate-guarding was vigorous and effective. Males did not respond to apparent sperm competition with forced-pair copulation, physical punishment, or abandonment of their mates. I found no negative correlation between degree of female promiscuity and the amount of parental care her mate gave to the entire brood. Males also did not reduce paternal care given to the young most likely to be the result of an EPC. I hypothesize that males are constrained in the behaviors they can use to avoid misplaced paternity in this species. While male mate-guarding reduces the opportunities for female involvement in EPC, the behaviors used by males to protect paternity apparently have not prevented the evolution of female receptiveness during EPC attempts. 相似文献
20.
In socially monogamous species, extra-pair paternity may increase the reproductive success of highly ornamented males, mediating the evolution of sexual ornaments. However, ornaments may also attract social mates, and a tradeoff between extra-pair paternity (EPP) and within-pair paternity (WPP) may complicate mating strategies. Further, in many socially monogamous species, females are also ornamented, and the relationship between female ornamentation and patterns of EPP has been neglected. We investigated the patterns of genetic paternity with respect to carotenoid- and melanin-based pigmentation in yellow warblers (Setophaga petechia) of both sexes. We asked whether males face tradeoffs between EPP and WPP, how paternity patterns relate to carotenoid- versus melanin-based pigmentation, and whether less EPP occurs in broods when males and females are assortatively paired. Males faced a tradeoff between EPP and WPP. Moreover, non-additive relationships existed between paternity patterns and the two pigment types in both sexes. Males with high melanin coverage but dull carotenoid pigmentation achieved EPP but lost WPP, whereas males with high levels of both pigment types had high WPP but gained little EPP. A parallel pattern occurred in females. Warblers paired assortatively by pigmentation and EPP was less common in broods when the sexes were assortatively paired by carotenoid pigmentation. Results suggest that the most colorful birds obtain high quality social mates and advance reproductive success through WPP, show that correlations can arise between female ornamentation and patterns of EPP, and also uniquely suggest that social pairing patterns may influence extra-pair mating strategies. 相似文献