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1.
Ola Svensson Maria Lissåker Kenyon B. Mobley 《Behavioral ecology and sociobiology》2010,64(8):1325-1331
When parental care is costly, parents should avoid caring for unrelated young. Therefore, it is an advantage to discriminate
between related and unrelated offspring so that parents can make informed decisions about parental care. In the present study,
we test the hypothesis that male sand gobies (Pomatoschistus minutus) recognize and differentially care for their own offspring when given a choice between a nest with sired eggs and a second
nest with eggs sired by an unrelated male. The sand goby is a species with exclusive and costly paternal care. Male parasitic
spawnings (e.g., sneaking) as well as nest takeovers by other males are common. Our results show that nests containing sired
eggs were preferred and received significantly more care, as measured by nest building and nest occupancy, than nests with
foreign eggs even when males cared for both nests. These findings suggest that males respond to paternity cues and recognize
their own clutches. Relative clutch size also had a significant effect on male parental care. When sired clutches were larger
than foreign clutches, males preferred to care for their own nest. In the few cases where males chose to take care of foreign
nests, the foreign clutch was larger than their own clutch. Taken together, our results provide evidence that both paternity
cues and clutch size influence parenting decisions among male sand gobies. 相似文献
2.
Parental care is a costly part of reproduction. Hence, natural selection should favor males which avoid caring for unrelated
young. However, the decision to abandon or reduce care requires cues which are evaluated to give information on potential
reproductive value of the offspring. The prediction that male sand gobies, Pomatoschistus minutus, care for foreign eggs as long as they were spawned in their own nest and at least some of such cues are fulfilled was tested.
Egg-guarding males that had recently taken part in a spawning event were given a clutch of eggs that was sired either by themselves
or another male, in either their own or another male’s aquarium. Males that had not taken part in a spawning event were used
as controls and were given eggs sired by another male. We measured the amount of filial cannibalism and nest building. Control
group males did not care for eggs and ate them all before rebuilding the nest. In the other treatments, there were no significant
effects of paternity, though males moved to another male’s aquarium increased their clutch area threshold and completely consumed
larger clutches than males that were not moved. There was no intermediate response in any treatment in the form of increased
partial filial cannibalism or less well-constructed nests. Our results suggest that egg-guarding males cannot distinguish
between eggs sired by themselves and those sired by other males but are able to react to cues indicating paternity state.
Males do not adopt eggs to attract females in P. minutus. 相似文献
3.
Laaksonen T Adamczyk F Ahola M Möstl E Lessells CK 《Behavioral ecology and sociobiology》2011,65(2):257-264
Female birds might be able to manipulate the parental effort of their male partner through elevated transfer of hormones to
the eggs, since these hormones affect many chick traits that males might use as cues for adjusting the level of their investment.
We experimentally studied whether female pied flycatchers Ficedula hypoleuca could manipulate male investment via yolk androgens. There is much more variation in yolk androgen levels between females
than within clutches, and in order to change the androgen levels of the eggs, we swapped whole clutches between nests. To
estimate the androgen levels of the clutch, we measured the androgen content of a single egg per clutch. Females did not succeed
in manipulating male effort using yolk androgens, since there was no relationship between the division of parental care within
a pair and either original or foster egg androgen levels. One of these relationships should have occurred if females were
manipulating males. The proportion of feeding visits by the male was higher when the male was old (55%) than when he was young
(45%) and females laid eggs with higher androgen levels when mated with a young male. Young males did not exhibit any responses
to yolk androgen levels either, which indicates that females cannot exploit their effort more than that of old males. We suggest
that females may allocate yolk androgens to adjust the growth trajectories of the chicks to poor growing conditions when mated
with young males that are poor providers or occupying a poor territory. 相似文献
4.
Paternal care and egg survival both increase with clutch size in the fathead minnow,Pimephales promelas 总被引:4,自引:0,他引:4
R. C. Sargent 《Behavioral ecology and sociobiology》1988,23(1):33-37
Summary In some species of fishes with paternal care, females prefer to spawn with males who are already defeding eggs; moreover, in many species, paternal care increases with the number of eggs that a male is defending. If egg survival depends on the level of paternal care, and is largely independent of egg number, then egg survival should increase with clutch size. This result would provide a potential adaptive mechanism for female preference for males with eggs. I examined the effects of clutch size on paternal care and egg survival in the fathead minnow, Pimephales promelas, and found that both increased with male clutch size. 相似文献
5.
Parents adjust care in response to weather conditions and egg dehydration in a Neotropical glassfrog
Jesse R. J. Delia Aurelio Ramírez-Bautista Kyle Summers 《Behavioral ecology and sociobiology》2013,67(4):557-569
Parental hydration of terrestrially developing eggs has evolved repeatedly among frogs and is thought to buffer embryos from environmental variation. While many anurans offer relevant opportunities to study parental care, research on how parents respond to environmental variation and offspring conditions are lacking. In this study, we investigated the interrelationships of weather, embryo hydration demands, and parental provisioning in a wild population of the glassfrog Hyalinobatrachium (‘Centrolenella’) fleischmanni in Oaxaca, Mexico. We determined whether males modify parental behavior in response to changes in weather conditions that effect embryo dehydration, how variation in both weather and parental hydration affect egg water balance and embryonic mortality, and whether parental provisioning is related to the hydration levels of egg clutches. We found that male H. fleischmanni compensate for environmental variation in offspring conditions by adjusting the frequency of parental care in response to both weather and egg dehydration. Using a male removal experiment, we examined the function of paternal care and made comparisons with previous research, finding that both the adaptive value of parental care and flexibility in parental behavior are impacted by spatial and temporal conditions. We present observations that indicate a direct conflict between providing parental care and multiple matings. In summary, this research demonstrates that the variable frequency of paternal care in H. fleischmanni is a response to the fluctuating nature of the climate and resulting hydration requirements of embryos in combination with the allocation of effort to parental care versus mating activity. 相似文献
6.
Devon E. Pearse Fred J. Janzen John C. Avise 《Behavioral ecology and sociobiology》2002,51(2):164-171
When females receive no direct benefits from multiple matings, concurrent multiple paternity is often explained by indirect genetic benefits to offspring. To examine such possibilities, we analyzed genetic paternity for 1,272 hatchlings, representing 227 clutches, from a nesting population of painted turtles (Chrysemys picta) on the Mississippi River. Goals were to quantify the incidence and distribution of concurrent multiple paternity across clutches, examine temporal patterns of sperm storage by females, and deduce the extent to which indirect benefits result from polyandrous female behaviors. Blood samples from adult males also allowed us to genetically identify the sires of surveyed clutches and to assess phenotypic variation associated with male fitness. From the genetic data, female and male reproductive success were deduced and then interpreted together with field data to evaluate possible effects of female mating behaviors and sire identity on offspring fitness. We document that more than 30% of the clutches were likely fathered by multiple males, and that presence of multiple paternity was positively correlated with clutch size. Furthermore, the data indicate that the second male to mate typically had high paternity precedence over the first. 相似文献
7.
Elisabet Forsgren Anna Karlsson Charlotta Kvarnemo 《Behavioral ecology and sociobiology》1996,39(2):91-96
In some fish species with paternal care, females prefer to spawn with males whose nests already contain eggs. Several hypotheses
have been put forward to explain this behaviour, such as reduced risk of predation or cannibalism (the dilution effect), increased
parental investment, and mate copying. This experimental study focuses on female mate choice in the sand goby, Pomatoschistus minutus. Females were found to choose males with eggs in their nests. In addition, hatching success increased with clutch size, mainly
because males with larger clutches showed less filial cannibalism. Increased egg survival in large clutches may thus be explained
by a combination of the dilution effect and higher parental investment. In another experiment, females did not seem to copy
the observed mate choice of other females. In conclusion, female preference for males with eggs in their nests is adaptive,
and can be explained by direct benefits, as more surviving offspring are produced.
Received: 23 December 1995/Accepted after revision: 11 May 1996 相似文献
8.
Recent theoretical models predict that the relative allocation to advertisement and parental care depends on whether paternal
care is necessary for offspring survival: In species with exclusive male care, male investment in attraction is expected to
reliably indicate paternal care effort and male phenotypic quality. Previous research, yielding contrasting results, has considered
how one trait involved in mate attraction interacts with parental care or a specific aspect of male quality. In the blenny
Salaria pavo, we perform a comprehensive analysis of the interplay between overall male attractiveness and male quality, the latter in
terms of fertility, condition, and parental care. In this fish, males are larger than females, exhibit two sexually dimorphic
traits (head crest and anal glands), and solely care for eggs. We generated a male attractiveness index through principal
component analyses of morphological traits and quantified parental effort as the total time spent in egg care. In addition,
we analyzed the relationships between specific components of attractiveness and male qualities. In agreement with theory predictions,
we found that male overall attractiveness is a reliable indicator of fertility, in terms of sperm number, but is unrelated
to body condition and parental care effort, with males able to perform high levels of care regardless of their level of advertisement.
However, the relative expression of head crest area appears positively related to sperm number but is traded-off with parental
care effort. These findings underline the need, in addressing real patterns, to consider interactions between multiple aspects
of male display and quality. 相似文献
9.
Elise Huchard Alexandra Alvergne Delphine Féjan Leslie A. Knapp Guy Cowlishaw Michel Raymond 《Behavioral ecology and sociobiology》2010,64(5):769-781
In mammals, fathers are facultative caretakers, and male care is expected to evolve only if it is directed towards related
young. Yet, in several promiscuous primate societies, males seem to care for infants despite a presumably low paternity confidence.
In cercopithecines, cohesive associations (‘friendships’) between a lactating female and an adult male are frequent and provide
the female and her infant with protection against various sources of aggression, including infanticide. However, the benefits
gained by males through such relationships remain unclear, in part, because the relatedness between males and their protected
infants has rarely been examined. Moreover, little is known about the nature of the cues underlying kin discrimination by
males in societies where females mate polyandrously. In this study, we combine behavioural and genetic data from wild chacma
baboons (Papio ursinus) in Namibia to investigate (1) whether males are related to their friend’s infant and (2) whether similarity between the
major histocompatibility complex (MHC) genotype of males and infants (potentially perceived through odour phenotype) favours
the establishment of friendships. We first show that males share close genetic ties with their friend’s infants, most often
by having sired the infant. Secondly, we find that male–infant MHC (Class II–DRB) similarity, in contrast to paternity, does not predict male–infant associations. Overall, our results clarify the nature
of the evolutionary benefits gained by males in these heterosexual associations, which can be considered as true paternal
care. However, the proximate mechanisms underlying paternity recognition remain to be identified. 相似文献
10.
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
11.
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
12.
Kai Lindström 《Behavioral ecology and sociobiology》1998,42(2):101-106
This study tested experimentally whether clutch size and the cost of care affect filial cannibalism in the sand goby, Pomatoschistus minutus. Evolutionary models of filial cannibalism suggest that egg eating has evolved as a way for the male parent to prolong his
breeding season. These models assume that eggs function as an alternative energy source for the constrained parent. I manipulated
clutch size by allowing males to mate with either one or two females, representing a small and a large clutch, respectively.
The addition of a small male shore crab, a common egg predator, increased the cost of care. I quantified fat reserves as a
measure of the condition of guarding males. Males who did not build nests had lower fat reserves than males who built nests,
suggesting that males with low energy reserves do not start breeding. Males with small clutches lost their nest to the crab
more often than males with large clutches. Neither filial cannibalism nor the amount of eggs eaten were affected by the treatments.
Males who consumed eggs had a higher fat percentage than males who did not eat eggs. The result that males with small clutches
lost their nests to the crabs supports the idea that eggs are defended only if the benefit from continued care will outweigh
the cost and that males therefore are sensitive to the trade-off between present and future reproductive success.
Received: 15 May 1997 / Accepted after revision: 15 November 1997 相似文献
13.
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
14.
Vedder O Magrath MJ Niehoff DL van der Velde M Komdeur J 《Behavioral ecology and sociobiology》2012,66(4):603-612
Although functional explanations for female engagement in extra-pair copulation have been studied extensively in birds, little
is known about how extra-pair paternity is linked to other fundamental aspects of avian reproduction. However, recent studies
indicate that the occurrence of extra-pair offspring may generally decline with laying order, possibly because stimulation
by eggs induces incubation, which may suppress female motivation to acquire extra-pair paternity. Here we tested whether experimental
inhibition of incubation during the laying phase, induced by the temporary removal of eggs, resulted in increased extra-pair
paternity, in concert with a later cessation of laying, in blue tits (Cyanistes caeruleus). As expected, experimental females showed a more gradual increase in nocturnal incubation duration over the laying phase
and produced larger clutches than controls. Moreover, incubation duration on the night after the first egg was laid predicted
how extra-pair paternity declined with laying order, with less incubation being associated with more extra-pair offspring
among the earliest eggs in the clutch. However, incubation duration on this first night was unrelated to our experimental
treatment and independent of final clutch size. Consequently, the observed decline in extra-pair paternity with laying order
was unaffected by our manipulation and larger clutches included proportionally fewer extra-pair offspring. We suggest that
female physiological state prior to laying, associated with incubation at the onset of laying, determines motivation to acquire
extra-pair paternity independent of final clutch size. This decline in proportion of extra-pair offspring with clutch size
may be a general pattern within bird species. 相似文献
15.
Nga Nguyen Russell C. Van Horn Susan C. Alberts Jeanne Altmann 《Behavioral ecology and sociobiology》2009,63(9):1331-1344
Close associations between adult males and lactating females and their dependent infants are not commonly described in non-monogamous
mammals. However, such associations [sometimes called “friendships” (Smuts 1985)] are regularly observed in several primate species in which females mate with multiple males during the fertile period.
The absence of mating exclusivity among “friends” suggests that males should invest little in infant care, raising questions
about the adaptive significance of friendship bonds. Using data from genetic paternity analyses, patterns of behavior, and
long-term demographic and reproductive records, we evaluated the extent to which friendships in four multi-male, multi-female
yellow baboon (Papio cynocephalus) groups in Amboseli, Kenya represent joint parental care of offspring or male mating effort. We found evidence that mothers
and infants benefited directly from friendships; friendships provided mother–infant dyads protection from harassment from
other adult and immature females. In addition, nearly half of all male friends were the genetic fathers of offspring and had
been observed mating with mothers during the days of most likely conception for those offspring. In contrast, nearly all friends
who were not fathers were also not observed to consort with the mother during the days of most likely conception, suggesting
that friendships between mothers and non-fathers did not result from paternity confusion. Finally, we found no evidence that
prior friendship increased a male’s chances of mating with a female in future reproductive cycles. Our results suggest that,
for many male–female pairs at Amboseli, friendships represented a form of biparental care of offspring. Males in the remaining
friendship dyads may be trading protection of infants in exchange for some resources or services not yet identified. Our study
is the first to find evidence that female primates gain social benefits from their early associations with adult males.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Brady A. Porter Anthony C. Fiumera John C. Avise 《Behavioral ecology and sociobiology》2002,51(4):350-359
In a variety of fish species with paternal care of offspring, females prefer to spawn in nests that already contain eggs.
This female preference has been hypothesized to explain egg thievery in male sticklebacks, allopaternal care of eggs in minnows,
and the evolution of egg-mimicking body features in male cichlids and darters. Here we employ microsatellite-based parentage
analyses to evaluate the reproductive success of striped darter (Etheostoma virgatum) males that appear to utilize two of these functionally related tactics to entice females to spawn in their nests. In an
isolated population (Clear Creek, Ky.), we observed that breeding males develop conspicuous white spots on their pectoral
fins. If these spots are egg mimics, as we suspect, then this represents the fourth independent evolutionary origin of egg
mimicry documented to date in darters, the first based on pigmentation (as opposed to physical structures), and the first
in which the egg mimics vary greatly in number among males. From direct counts of microsatellite genotypes in clutches of
embryos, at least 3.8 females contributed to the progeny within a typical nest, and females tended to spawn preferentially
with males that were larger and displayed more egg-mimic spots. In another population (Hurricane Creek, Tenn.) without egg
mimics, the multi-locus genetic data document that allopaternal care is common, especially among the smallest males who sometimes
tend nests containing their own as well as an earlier sire's offspring. Thus, these foster males had adopted egg-containing
nests and then successfully spawned with subsequent females. Overall, the genetic data on paternity and maternity, in conjunction
with field observations, suggest that egg mimicry and allopaternal care are two mate-attracting reproductive tactics employed
by striped darter males to exploit female preferences for spawning in nests with 'eggs'.
Electronic Publication 相似文献
17.
Contrary to Bateman’s principle, polyandry appears to be a common female mating strategy. Several hypotheses have been proposed
to explain the evolution of polyandry. It is assumed that females gain either material or genetic benefits from multiple matings,
or that they are coerced into mating by males. In water striders, mating is generally assumed to be costly to females, and
they are thought to mate for reasons of convenience, adjusting their resistance to mating according to male harassment. Here,
we tested the effect of number of matings (with the same male) and number of partners on female fitness in a water strider
Aquarius paludum. In the first experiment, we regulated the time females spent with a male and found that females’ egg production increased
with multiple matings up to a point. The result supports the existence of an optimal female mating frequency. In the second
experiment, we tested how polyandry affects the number of eggs laid and egg hatching success. We conducted three different
trials: females mated four times with either a single male, two different males, or with four different males. Females that
mated with four different males laid the lowest number of eggs and had the lowest egg hatching success, suggesting that polyandry
reduces females’ egg production and egg hatching success in A. paludum. We conclude that A. paludum females probably gain material benefits from mating but no genetic benefits were found in this study. 相似文献
18.
Females mating with multiple males may obtain direct benefits such as nuptial gifts or paternal care or indirect (i.e. genetic)
benefits resulting in higher-quality offspring. While direct benefits are easily identified, it is difficult to determine
indirect benefits, and it is hence largely unclear how they are obtained. This is particularly true in species with external
fertilisation, where females seem to have little control over fertilisation. In cichlids, most maternal mouthbrooders show
sequential multiple mating, where females visit several males for egg deposition. Genetic data revealed that multiple paternity
of eggs and young in the mouth of females is common, but behavioural data of female spawning decisions are missing. Here,
we test four hypotheses to explain female multiple mating in the maternally mouthbrooding cichlid, Ophthalmotilapia ventralis: (1) fertilisation insurance, (2) genetic bet-hedging, (3) female choice and (4) ‘sperm shopping’ (i.e. induction of sperm
competition resulting in sexually selected sperm). Detailed observations of spawning behaviour in the field combined with
histological analyses of the male reproductive organs suggest that fertilisation insurance, genetic bet-hedging and pre-mating
female choice are unlikely to explain the sequential female multiple mating in O. ventralis. Instead, cryptic female choice by sperm shopping, i.e. post-mating sexual selection, is most compatible with our data and
might be the major ultimate cause of multiple mating in females of this species and of mouthbrooding cichlids with maternal
care in general. Our study provides new insight into ultimate causes of sequential polyandry in species with external fertilisation,
as hitherto post-mating sexual selection by cryptic female choice has been assumed to be incompatible with external fertilisation
mechanisms except by components of the ovarian fluid. 相似文献
19.
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
20.
Impressive variation in egg colouration among birds has puzzled evolutionary biologists for a long time. The most frequently
studied selective forces moulding egg colouration—predation and brood parasitism—have either received little empirical support
or may play a role in only a minority of species. A novel hypothesis has suggested that egg colour may be significantly influenced
by sexual selection. Females may deposit a blue-green pigment biliverdin into eggshells instead of using it for themselves
as a powerful antioxidant. By this handicap, females may signal their quality to males, which are then hypothesized to increase
their paternal effort. We experimentally tested the hypothesis in the collared flycatcher (Ficedula albicollis), a species laying blue-green eggs. We cross-fostered clutches between nests to disentangle effects of female/territory quality
and egg colour on paternal effort and nestling quality. The results supported two assumptions of sexual signalling through
egg colour hypothesis: Blue pigment seems to be a limited resource for females, and female quality is positively correlated
with the intensity of the blue-green colour. However, we did not find support for the main prediction of the hypothesis, as
male parental effort parameters (feeding frequencies to nestlings and intensity of nest defence) were unrelated to egg colour.
We discuss possible reasons for the discrepancy between our results and previous correlative analyses that supported the hypothesis
that blue egg colour may be a postmating, sexually selected signal in females. 相似文献