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1.
Summary. Many animals use carotenoid pigments to color their integument and become
sexually attractive. These colorants can also serve physiological functions,
protecting cells and tissues from oxidative damage as well as stimulating the immune system.
Because animals often acquire several different carotenoid pigments from their diet,
there is the potential for different carotenoids to exhibit different free-radical-scavenging
or immunoenhancing activity. We experimentally tested how two common dietary
xanthophylls - lutein and zeaxanthin - may differentially affect the immune system in
male zebra finches (Taeniopygia guttata). Male
T. guttata derive their red sexual beak colorants from these two carotenoids, and
prior studies with this species have shown that lutein and zeaxanthin together boost cell-mediated
immunity. We experimentally elevated these two dietary carotenoids separately in two
groups of non-breeding zebra finches, but found that lutein-supplemented and zeaxanthin-supplemented
males mounted similar cell-mediated immune responses (to phytohaemagglutinin, or PHA).
Although zeaxanthin is a more conjugated carotenoid than lutein and has the potential
to be a more potent antioxidant, our study suggests that such a subtle structural
difference between these two biochemicals does not differentially affect immune
performance in this songbird. 相似文献
2.
Carlos Navarro Tomás Pérez-Contreras Jesús M. Avilés Kevin J. McGraw Juan J. Soler 《Behavioral ecology and sociobiology》2010,64(7):1209-1067
Many colourful sexually selected signals in animals are carotenoid-dependent and, because carotenoids function as antiradicals
and immunostimulating molecules, carotenoid-dependent signals may honestly reflect the health state of individuals. Some others
nutrients like vitamin A may also enhance health and colouration, but these have rarely been tested alongside carotenoids
in colourful birds. Here, we examined whether beak colour of the spotless starling (Sturnus unicolor) reflected circulating levels of carotenoids and/or vitamin A (retinol). Spotless starlings are polygynous, sexually dimorphic
birds (i.e. length of chest feathers). The tip of the beaks of male and female spotless starlings is more intensely coloured
at the beginning of the breeding season and becomes dull after mating, which may suggest a sexual function. We found that
females have a more intensely coloured beak and higher plasma carotenoid concentration than males during mating, and, despite
the finding that carotenoid and vitamin A levels were not significantly related; colour intensity was positively correlated
with plasma concentration of carotenoids and vitamin A in both sexes. However, adult beak coloration was not associated with
carotenoid and vitamin A concentrations after nestlings were hatched. Therefore, beak colouration of spotless starlings provides
information about circulating levels of carotenoids and vitamins during the mating season and may potentially function as
a reliable signal of physiological status in the context of sexual selection. 相似文献
3.
Sarah A. Collins Christene Hubbard Anne M. Houtman 《Behavioral ecology and sociobiology》1994,35(1):21-25
Studies of female mate preference in zebra finches (Taenopygia guttata) have shown that male beak colour and song rate are important. However, the two characters are correlated. Here the effect of beak colour and song rate on female choice are examined independently. In mate choice tests involving two males, beak colour was manipulated artificially using nail varnish. The results showed that females showed a significant preference for males with a high song rate, but not with a red beak. Females did not prefer males with a red beak if song rate was low and females preferred males with orange beaks who expressed a high song rate. Female preference for males with red beaks was not found when beak and song characters were no longer correlated. 相似文献
4.
Carlos Navarro Tomás Pérez-Contreras Jesús M. Avilés Kevin J. Mcgraw Juan J. Soler 《Behavioral ecology and sociobiology》2010,64(7):1057-1067
Many colourful sexually selected signals in animals are carotenoid-dependent and, because carotenoids function as antiradicals and immunostimulating molecules, carotenoid-dependent signals may honestly reflect the health state of individuals. Some others nutrients like vitamin A may also enhance health and colouration, but these have rarely been tested alongside carotenoids in colourful birds. Here, we examined whether beak colour of the spotless starling (Sturnus unicolor) reflected circulating levels of carotenoids and/or vitamin A (retinol). Spotless starlings are polygynous, sexually dimorphic birds (i.e. length of chest feathers). The tip of the beaks of male and female spotless starlings is more intensely coloured at the beginning of the breeding season and becomes dull after mating, which may suggest a sexual function. We found that females have a more intensely coloured beak and higher plasma carotenoid concentration than males during mating, and, despite the finding that carotenoid and vitamin A levels were not significantly related; colour intensity was positively correlated with plasma concentration of carotenoids and vitamin A in both sexes. However, adult beak coloration was not associated with carotenoid and vitamin A concentrations after nestlings were hatched. Therefore, beak colouration of spotless starlings provides information about circulating levels of carotenoids and vitamins during the mating season and may potentially function as a reliable signal of physiological status in the context of sexual selection. 相似文献
5.
Michael Tobler Dennis Hasselquist Henrik G. Smith Maria I. Sandell 《Behavioral ecology and sociobiology》2010,64(5):717-727
Hormone-mediated maternal effects play an important role in the formation of a differentiated phenotype. They have been shown
to influence a wide array of offspring traits, both early in life and in adulthood. One important offspring trait that is
under the influence of maternal androgens is the immune system. In birds, a growing number of studies show that yolk androgens
modulate immune function during the chick stage. However, there is a lack of knowledge regarding long-term effects of prenatal
androgens on offspring immunity. In this study, we therefore investigated the influence of prenatal testosterone (T) on several
measures of immunity in fledgling and adult zebra finches (Taeniopygia guttata). Cell-mediated immune response (towards phytohaemagglutinin, PHA) of fledglings hatching from control eggs was negatively
related to brood size, whereas there was no such association for fledglings hatching from eggs with experimentally elevated
T levels (T fledglings). Male control fledglings showed reduced mass gain compared to female control fledglings within 24 h
after the PHA injection. This pattern was reversed in T fledglings. Total antibody levels in fledglings were not affected
by egg treatment. Neither cell-mediated immunity nor total antibody levels in sexually mature zebra finches were influenced
by egg treatment. However, there was an immuno-enhancing effect of elevated egg T on both primary and secondary humoral immune
responses toward diphtheria and tetanus antigens in ca 5 and 7 month old zebra finches. In addition, the covariation between
different immune components differed between T and control offspring, suggesting that egg treatment may have altered the potential
trade-offs between different parts of the immune system. Our results suggest that prenatal androgens could be an important
factor contributing to individual variation in immune function even in adulthood. 相似文献
6.
Henrik Brumm 《Behavioral ecology and sociobiology》2009,63(8):1157-1165
Bird song is a sexually selected multidimensional signal. A fundamental question regarding the evolution of sexually selected
signals is what information they convey and how their honesty is maintained. Song amplitude is a performance-related signal
trait that varies considerably between individuals, but this signal dimension has been neglected in past studies. I found
that median song amplitude in male nightingales (Luscinia megarhynchos) and zebra finches (Taeniopygia guttata) did not vary significantly with body size or residual body mass. In contrast, I found a significant negative correlation
between body size (and also residual mass) and the maximum song amplitude during interactive singing in nightingales. However,
the function of these more subtle differences in song amplitude remains to be investigated. By and large, the results of this
study suggest that mean song amplitude is unlikely to indicate a bird’s body size or current condition (measured as residual
mass). 相似文献
7.
Michael W. Butler Matthew B. Toomey Kevin J. McGraw 《Behavioral ecology and sociobiology》2011,65(2):401-413
For a variety of technical and conceptual reasons, biologists have come to use several different methods to quantify the colors
of animals. However, the relative abilities of these different color-scoring procedures to capture variation in the actual
color-generating mechanisms—pigment or structural composition of the integument—have never been tested systematically. Here,
we examined which commonly employed color metrics predict carotenoid content of ornaments in three avian species (house finch
Carpodacus mexicanus, mallard duck Anas platyrhynchos, and zebra finch Taeniopygia guttata). We used spectrophotometry to measure reflectance spectra from beak and feather tissue, calculated numerous color metrics
(e.g., hue, chroma, brightness, principal components, and tetrahedral color space position) from these spectra, and determined
carotenoid content at the site of color measurement with high-performance liquid chromatography. We found that several principal
component, tristimulus, and avian visual model metrics significantly correlated with carotenoid content of house finch feathers
and duck beaks. Carotenoid content of mallard beaks was most closely correlated with brightness and saturation metrics, whereas
in house finch feathers, carotenoid concentration was best captured by hue and saturation metrics. According to tristimulus
scores and visual models, we found that the ultraviolet portion of the spectrum was not an essential predictor of variation
in carotenoid content. Also, visual model chromatic contrasts generally were not significant predictors of carotenoid content,
although some achromatic contrasts and tetrahedral color space vector parameters were. Our results indicate that numerous
methods, especially tristimulus scores, are suitable for capturing pigment-based color variation in two carotenoid-containing
ornaments, and we discuss the merits and shortcomings of these different approaches. In contrast, there were no significant
relationships between any color metrics and the carotenoid content of zebra finch beaks, suggesting that other color-generating
mechanisms besides carotenoids may contribute to color variability in this species. 相似文献
8.
Joanna Rutkowska Tomasz Wilk Mariusz Cichoń 《Behavioral ecology and sociobiology》2007,61(8):1211-1217
There is accumulating evidence that maternal hormones may play a role in offspring sex adjustment, but little is known about
the costs of such hormone-mediated mechanisms. Recent studies have reported sex-specific effects of hormones on offspring
viability. Specifically, we previously found that elevating the plasma androgen level in mothers results in a male-biased
offspring primary sex ratio, but it affects the viability of sons negatively and daughters positively in zebra finches (Taeniopygia guttata; Rutkowska and Cichoń, Anim Behav, 71:1283–1288, 2006). In this study, we studied further fitness consequences of exposure
to elevated yolk androgen levels in zebra finches. We measured growth rate and cellular immune response of nestlings that
hatched from eggs laid by females injected with testosterone during egg laying and nestlings of unaffected control females.
We found that sons of testosterone-treated females grew slower in comparison to sons of control females. The significant interaction
between experimental group and offspring sex indicates that sons of testosterone-treated mothers suffered impaired immune
responsiveness while daughters seemed to benefit from elevated androgen level in terms of enhanced immune responsiveness.
We found no effects of androgens on offspring performance at adulthood—neither fecundity of females nor attractiveness of
males was affected. We conclude that the benefits of biasing sex ratio towards males by increasing androgen level in the yolk
may be limited due to negative effects on male offspring performance early in life. 相似文献
9.
Tim Ruploh Hans-Joachim Bischof Nikolaus von Engelhardt 《Behavioral ecology and sociobiology》2014,68(4):537-549
Group-living animals rely on social skills which ensure beneficial interaction and prevent harmful ones with conspecifics. In a previous experiment, we demonstrated that male zebra finches reared in groups during adolescence show consistently less courtship and aggressive behaviour as adults than pair-reared males. Here we tested whether such differences affect how they group with conspecifics, as an indicator of their social integration. Zebra finches were kept in pairs (male–female or male–male) or mixed-sex groups (three males and three females) during adolescence and were introduced to an established group of unknown conspecifics during adulthood. Male courtship and aggressive behaviour were quantified directly after introduction to the group and 48 h later. At the same time, male position in relation to other birds and the number of birds in proximity were recorded. Males that grew up in a small mixed-sex group during adolescence spent more time within groups, were observed in bigger groups and lost less weight than males raised in pairs, indicating that an enriched social environment during early development may facilitate social integration. However, we observed no differences in courtship and aggressive behaviour that could predict the differences in grouping behaviour of pair- and group-reared males. We discuss alternative explanations for the difference in grouping and how to test these in future research. 相似文献
10.
Tim Ruploh Hans-Joachim Bischof Nikolaus von Engelhardt 《Behavioral ecology and sociobiology》2013,67(2):175-184
Adolescence is the pivotal transitional phase during which animals become sexually and socially mature and acquire the skills to cope with a variety of environmental challenges on their own. We investigated in a bird species, the zebra finch, how the social environment experienced during this period influences their behaviour in a sexual context. Zebra finches were kept in pairs (male–female or male–male) or larger mixed-sex groups (three males and three females) during adolescence and the long-term consequences were studied on courtship behaviour, aggressiveness and attractiveness in 42 males. To investigate the stability of the observed effects over time, all behavioural tests were repeated approximately 4 months after the initial recordings. Males that grew up with a single female showed the most intense courtship and highest aggressiveness and were most attractive to females, while group-reared males had the lowest courtship and aggressiveness and were the least attractive. The observed differences in courtship and aggressiveness were stable, while the differences in attractiveness disappeared over time. These findings are very similar to earlier studies on guinea pigs, indicating that the observed effects represent a general phenomenon, not restricted to mammals with a similar function and presumably also similar underlying mechanisms. 相似文献
11.
Food restrictions early in life can have adverse effects on the development of adult avian song structure. Nutritional deficiencies
during brain development are thought to impair the growth of neural circuits responsible for learning and production of song
in adulthood. Thus, the quality of song may reflect the quality of the singer due to the costs associated with neural development
early in life. Recent investigations have focused on domesticated laboratory strains of zebra finches where early dietary
deficiencies have significantly reduced the complexity of song and its sexual attractiveness. Domesticated zebra finches may
be more sensitive to the early effects of moderate under-nutrition on song complexity than their non-domesticated counterparts.
In an aviary experiment with non-domesticated zebra finch stock, we found that song complexity when measured by a linear combination
of six variables was reduced in food-restricted birds, with syllable rate and maximum syllable frequency as the principal
variables affected. The restriction had no effect on learning accuracy when song phrases of experimental birds were compared
to those of their fathers.This result demonstrates that early nutrition may differentially affect the development of neural
processes that influence learning accuracy and song complexity. While the finding of negative effects of dietary restriction
on song complexity is robust for zebra finches and is not an artefact of domestication, it does not explain why some nutritionally
stressed populations of wild zebra finches have more complex songs than those from other regions of Australia characterised
by greater food availability. 相似文献
12.
The hypothesis that sexual ornaments are honest signals of quality because their expression is dependent on hormones with
immune-depressive effects has received ambiguous support. The hypothesis might be correct for those signals that are carotenoid-dependent
because the required carotenoid deposition in the signal, stimulated by testosterone, might lower the carotenoid-dependent
immune defence of the organism. Two pathways underlying this androgen-dependent honest signaling have been suggested. Firstly,
androgens that are needed for ornament expression may suppress immune defence, a cost that only high-quality animals can afford.
Alternatively, immune activation may downregulate the production of androgens in low-quality individuals. Which of these alternatives
is correct, and to what extent these effects are mediated by the different metabolites of androgens, remain open questions.
To provide answers to these questions, we manipulated the levels of testosterone (T), 5α-dihydrotestosterone (DHT), and 17-β-estradiol
(E2) in diamond doves Geopelia cuneata, a species in which both sexes exhibit a carotenoid-dependent, androgen-regulated red–orange periorbital ring of bare skin.
On the first day of the experiment (day 0), we inserted steroid-releasing implants into groups of birds and on day 14, we
subjected half of the birds to an immunological challenge by immunizing them with sheep red blood cells (SRBC). In females,
but not in males, androgen but not estradiol treatments reduced antibody production to SRBC. In addition, the immunological
challenge reduced redness and size of the trait as well as androgens levels in both sexes and in all treatments. This indicates
that an immunological challenge can lower circulating T at the cost of the trait expression. These findings are in accordance
with both pathways postulated in the immunocompetence-handicap hypothesis, but do not entirely support the idea that the immunosuppressive
effect of androgens yields honest signaling since both T and DHT were not immunosuppressive in males, for which sexual signaling
is supposed to be especially important. 相似文献
13.
The attractiveness of an individual (i.e. its ability to arouse interest in a potential mate) has important implications for
its reproductive success. However, attractiveness is not a fixed trait. Previous work has shown that male birds can adjust
the intensity of their courtship display in response to variation in female behaviour, but little is known about how males
adjust their behaviour during mate choice in response to social feedback about their own attractiveness independent of their
intrinsic quality. Such information may help to maximize the potential mating success of males. Here, we provide experimental
evidence that the amount of attention given by male zebra finches to females is dependent upon the manipulated attractiveness
of males. This demonstrates that, in this socially monogamous species of bird, attractiveness of males could be considered
to be a social construct, at least partially determined via social feedback from females. 相似文献
14.
K. A. Spencer J. H. Wimpenny K. L. Buchanan P. G. Lovell A. R. Goldsmith C. K. Catchpole 《Behavioral ecology and sociobiology》2005,58(4):423-428
Developmental stress has recently been shown to have adverse effects upon adult male song structure in birds, which may well act as an honest signal of male quality to discriminating females. However, it still remains to be shown if females can discriminate between the songs of stressed and non-stressed males. Here we use a novel experimental design using an active choice paradigm to investigate preferences in captive female zebra finches (Taeniopygia guttata). Nine females were exposed to ten pairs of songs by previously stressed and non-stressed birds that had learned their song from the same tutor. Song pairs differed significantly in terms of song complexity, with songs of stressed males exhibiting lower numbers of syllables and fewer different syllables in a phrase. Song rate and peak frequency did not differ between stressed and non-stressed males. Females showed a significant preference for non-stressed songs in terms of directed perching activity and time spent on perches. Our results therefore indicate that developmental stress affects not only the structure of male song, but that such structural differences are biologically relevant to female mate choice decisions. 相似文献
15.
Summary. Geckos consumed immature Bactrocera carambolae males readily, but their consumption was reduced significantly when offered sexually mature males. They showed a similar
aversion for sexually mature males previously fed with methyl eugenol. When male flies at different ages were offered to starved
geckos, geckos’ consumption showed an age-related anti-feeding effect, which was concomitant with the production trend of
6-oxo-1-nonanol, a major endogenous component synthesized in the male rectal gland. The production of 6-oxo-1-nonanol was
also age-related and corresponded with sexual maturity as reported previously. Topical application of the authentic chemical
of 6-oxo-1-nonanol onto the thorax of female fruit flies, at the amount normally detected in the rectal gland of a sexually
mature male, had the same deterrent effect against geckos. 相似文献
16.
E. C. Pariser L. Gilbert N. Hazon K. E. Arnold J. A. Graves 《Behavioral ecology and sociobiology》2012,66(4):519-527
Females are expected to partition resources between offspring in a context-dependent way to maximise total fitness returns
from a reproductive attempt. Female zebra finches (Taeniopygia guttata) vary the allocation of yolk androgens and antioxidants among offspring. Importantly, the balance between androgens and antioxidants
in yolks may be more important than their independent absolute amounts in terms of fitness consequences for developing young.
Therefore, we tested whether the relative allocation of these two resources in yolks varies according to either the Trivers–Willard,
positive or compensatory maternal investment hypothesis. We manipulated male attractiveness using coloured leg bands (red-banded
males appear attractive; green-banded males, unattractive) and measured yolk androgens and antioxidants in each egg, egg sex,
clutch sex ratio and female condition. While female zebra finches manipulated the balance of androgens and antioxidants within
and between clutches in response to mate attractiveness, offspring sex and their own condition, they did not do so in a way
that consistently followed any of the hypotheses. Mothers paired with unattractive males allocated a larger antioxidant/androgen
ratio to daughters than sons. This pattern was reversed when paired to an attractive male; sons received a larger antioxidant/androgen
ratio than daughters. We also found offspring sex ratio decreased with increasing female condition for unattractive males,
but not for attractive males. However, without knowing the fitness consequences of the balance of different egg constituents,
it is difficult to interpret the patterns consistently in terms of the Trivers–Willard, compensatory and positive investment
hypotheses. 相似文献
17.
David Costantini Nosrat Mirzai Neil B. Metcalfe 《Behavioral ecology and sociobiology》2012,66(8):1195-1199
Biologists have long been interested in the behavioural and physiological mechanisms that regulate flight. The manipulation of physical activity of birds under captive conditions, however, faces the experimenter with some technical problems. In this article, we describe a simple automated system that allows control and manipulation of the flight activity of captive birds and use it for the first time to induce blood oxidative stress in male zebra finches (Taeniopygia guttata). Finches subjected to a short-term flight effort regime had an increase of plasma oxidative damage and a decrease of thiol concentration in red blood cells and of body mass, respectively. However, no change in red blood cell glutathione peroxidase was observed. This simple experiment shows that our automated system may be successfully used to induce changes in the physiological state of small birds. 相似文献
18.
A. P. Møller E. Flensted-Jensen W. Mardal 《Behavioral ecology and sociobiology》2007,61(10):1561-1571
Many different seabirds including terns have black color at the tip of their beak, but a yellow, orange, or red color of the
rest of the beak. The tip of the beak of Arctic terns Sterna paradisaea is black, while the rest of the beak is deep red during the breeding season. We hypothesized that the black coloration of
the tip of the beak is a reliable signal of phenotypic quality maintained by the costs of deposition of melanin. In this paper,
we tested a number of predictions arising from this hypothesis. Consistent with the hypothesis, we found that (1) Arctic terns
mated assortatively with respect to beak color score; (2) early breeding adults had larger beak color scores than late breeders;
(3) clutch size was larger in adults with large beak color scores; (4) adults with a small beak color scores were more likely
to die in the immediate future than individuals with large scores; and (5) beak color score was related to environmental conditions
at the breeding grounds, as reflected by the North Atlantic Oscillation and the amount of fertilizer used in agriculture,
and hence, leaking to coastal waters and environmental conditions at the Antarctic wintering areas as reflected by the Southern
Oscillation. These findings suggest that beak color score provide reliable information about individual phenotypic quality. 相似文献
19.
The complex songs of songbirds are thought to have evolved through sexual selection. Sexually selected signals must be associated
with costs in order to ensure their honesty as indicator of male quality. Costs may relate to the development of the neural
substrate underlying song learning, which develops already very early in life. Song may, therefore, serve as an indicator
of the early developmental history. This nutritional stress hypothesis has initially been confirmed for a variety of species,
but recent studies using zebra finches as a model species reported somewhat inconsistent effects, and the functional consequences
of changes in adult song phenotype remain unclear. We tested the nutritional stress hypothesis in canaries by manipulating
either the brood size or the food quality postfledging. The brood size manipulation had a significant effect on early development,
and low food quality postfledging led to a transient reduction in body mass. However, we did not find evidence that any of
the song traits measured reflected the early developmental conditions, which is in conflict with the nutritional stress hypothesis.
Canaries may be less vulnerable to nutritional stress or are able to compensate stressful conditions during early development.
However, if males compensated, this compensation may have come at a survival cost. Female mate choice decisions were independent
of the developmental history of a male. Instead, females preferred males singing longer song bouts, a trait that may contain
a heritable component. 相似文献
20.
Peter D. Dijkstra Renske Hekman Rüdiger W. Schulz Ton G. G. Groothuis 《Behavioral ecology and sociobiology》2007,61(4):599-609
The nature of the costs maintaining honesty of sexual signalling in inter- and intrasexual interactions remains a contentious
issue. For carotenoid-based colour ornaments, it has been hypothesized that the honesty of the signal is enforced when carotenoid
allocation to colour expression is traded off against carotenoid availability for immunocompetence. In addition, honesty is
enforced if androgens required for colour expression are immunosuppressive. We tested whether there is a trade-off between
colour expression and immunocompetence in a lek-breeding haplochromine cichlid fish, Pundamilia nyererei, from Lake Victoria with a carotenoid-based nuptial dress. First, we showed that expression of red nuptial colouration and
social rank in a group were positively correlated. We then successfully manipulated the level of colour advertisement by socially
stimulating individually housed males with a rival male: Stimulated males developed larger areas of red nuptial colouration
and had higher levels of circulating 11-ketotestosterone (11-KT) than non-stimulated males. We subsequently tested the humoral
immune response to a novel antigen (sheep red blood cells). There was no overall significant effect of social stimulation
on antibody production, but in the stimulated males, the degree of red colouration and the antibody response were negatively
correlated. This significant interaction between colour and treatment thus shows that the negative correlation between colouration
and antibody production is dependent on the (manipulated) social environment. This study provides correlational and experimental
evidence for a trade-off between expression of a sexual trait and one component of immune function in fish. We found no evidence
for a direct effect of 11-KT on antibody production, and we discuss alternative mechanisms that could mediate the trade-off. 相似文献