共查询到20条相似文献,搜索用时 31 毫秒
1.
Matteo Griggio Lorenzo Serra Davide Licheri Alessia Monti Andrea Pilastro 《Behavioral ecology and sociobiology》2007,61(3):423-433
Females often base their mating preferences on male sexual secondary traits that are used to settle contests among males. Such traits are likely to be honest indicators of male quality if they are constantly used during costly male–male agonistic interactions. Carotenoid signals have been shown to work as a handicap because they are costly to produce. However, the role of carotenoids as “honest” signals during male contests is less clear, and it is not known whether a carotenoid-based trait can serve in both male–male competition and female choice. In this study, we studied the dual function of a carotenoid feather ornament in the rock sparrow (Petronia petronia), a bird species in which both sexes have a yellow throat patch whose size positively correlates with phenotypic measures. First, we investigated, in a field study, whether the size of a male’s yellow patch correlates with his ability to acquire a territory. Second, we tested the signal function of the yellow patch in two male–male interaction in captivity experiments. Finally, we measured female preference for males differing in throat patch size in a mate choice experiment. Our experiments revealed that the size of a male’s throat patch positively correlated with the number of nest boxes he was able to defend. Moreover, in controlled conditions, males with relatively large yellow patches had earlier access to food than those with small patches. Also, in an experiment in which a dummy rock sparrow with an experimentally manipulated yellow patch was positioned near a feeder, latency to feed by focal birds positively correlated with dummy patch size. Lastly, in a dichotomous mate choice experiment, females showed a proximity preference for males whose patch was experimentally enlarged. Taken together, these results suggest that the same carotenoid feather signal may be used in both male–male competition and female choice in this passerine bird. 相似文献
2.
Mennill Daniel J. Doucet Stéphanie M. Montgomerie Robert Ratcliffe Laurene M. 《Behavioral ecology and sociobiology》2003,53(6):350-357
Sexual dichromatism and phenotypic variation in elaborate male traits are common products of sexual selection. The spectral properties of carotenoid and structurally-based plumage colors and the patch sizes of melanin-based plumage colors have received considerable attention as sexual signals in birds. However, the importance of variation in achromatic plumage colors (white, gray and black) remains virtually unexplored, despite their widespread occurrence. We investigated a potential signal function of the achromatic black and white plumage of black-capped chickadees (Poecile atricapilla). We captured and color-banded 178 free-living chickadees and assessed winter flock dominance hierarchies by tabulating pairwise interactions at feeders. We recaptured 73 of these birds and measured plumage coloration for six body regions using a reflectance spectrometer and the area of melanin-based plumage patches from standardized photographs. We found extensive individual variation in chickadee plumage traits and considerable sexual dichromatism. Male black-capped chickadees have significantly brighter white plumage than females, larger black patches, and greater plumage contrast between adjacent white and black plumage regions. We also found rank differences in the plumage reflectance of males; high-ranking males, who are preferred by females as both social and extra-pair partners, exhibit significantly darker black plumage and grow their feathers more rapidly than low-ranking males. This variation among individuals reveals a potential signal function for achromatic plumage coloration in birds. 相似文献
3.
Multiple traits may either signal different characteristics of a male or be redundant. These multiple signals may convey different
messages if they are intended for different receivers (e.g., male or females) that have different interests. We examined the
functions of multiple colorful visual traits of male Schreiber’s green lizard (Lacerta schreiberi). Results showed that interindividual variation in the characteristics of coloration of males can be related to variation
in morphology, health state, dominance status, and pairing status, but that different relationships were found for each color
signal. For example, dominant males had brighter “blue” throat and with higher values of ultraviolet (UV) and bluish coloration
and darker and greenish dorsal coloration than subordinate males. Health state was also reflected in coloration; males with
a higher immune response had “blue” throats with lower amounts of UV coloration, but had “yellow” chests with higher amounts
of UV coloration. Males found guarding females also differed in coloration from males found alone. These data suggest that
characteristics of coloration of the different multiple signals may reveal different messages for different receivers, either
male or female conspecifics. The development of the different signals, based on different morphological and physiological
mechanisms and trade-offs, may allow signal reliability of multiple colorful traits in different social contexts. 相似文献
4.
Delayed plumage maturation in Lazuli buntings: tests of the female mimicry and status signalling hypotheses 总被引:1,自引:0,他引:1
Vincent R. Muehter Erick Greene Laurene Ratcliffe 《Behavioral ecology and sociobiology》1997,41(4):281-290
The evolutionary importance of delayed plumage maturation (DPM) in passerines, the condition when more than 1 year is required
to achieve adult-like coloration, remains highly contentious. Adaptive hypotheses propose that aggression from after 2nd-year
(ASY) males or predation favors DPM in 2nd-year (SY) males, thereby increasing SY male survivorship or reproductive success.
However, each hypothesis suggests a distinct selective mechanism explaining “how” this is accomplished. Alternatively, DPM
may be a consequence of a nonadaptive molt constraint. We tested the female mimicry and status signalling hypotheses in territorial
ASY male lazuli buntings (Passerinaamoena) using three sets of model presentation experiments. The female mimicry hypothesis proposes that dull SY male plumage deceptively
mimics female plumage, and predicts that ASY males can not distinguish SY male from female plumage. The status signalling
hypothesis proposes that dull SY male plumage honestly signals low competitive threat, and predicts that ASY males respond
less aggressively to dull versus bright, ASY-like plumage. Contrary to the female mimicry hypothesis, ASY males distinguished
between SY male and female plumage, as they were aggressive to SY male models exclusively and attempted to copulate with female
models. Supporting the status signalling hypothesis, ASY males were significantly less aggressive to SY versus ASY male plumage.
While DPM may result from a physiological constraint on bright SY male plumage, our results support the idea that dull plumage
in an SY male's first breeding season may be maintained by selection to reduce aggression from ASY males, serving as a signal
of competitive status.
Received: 21 February 1997 / Accepted after revision: 16 June 1997 相似文献
5.
Evolutionary biologists have shown much recent interest in the costliness and signal content of colorful plumage displays in birds. Although many studies suggest that both carotenoid- and structurally-based plumage colors are condition-dependent indicators of health and nutritional state at the time ornamental feathers are grown, there is little experimental evidence supporting the idea that melanin pigmentation is a reliable signal of condition during molt. Instead, melanin-based ornamental coloration often reveals the competitive ability and dominance of individuals throughout the year. However, this work does not indicate which proximate environmental factors shape the expression of melanin pigmentation at the time of feather growth. Because of the link between melanin coloration and the social environment, it is possible that the development of brightly colored plumage may be associated with aggressive social interactions during feather molt. Here, we show that melanin-based ornamental coloration in male house sparrows (Passer domesticus) is correlated with the degree to which individuals interact aggressively with conspecifics during molt. Males that were dominant (beta, but not alpha) within captive social groups during molt grew larger badges than subordinates. Groups of males that had higher rates of aggression during molt grew larger badges than less aggressive triads. To our knowledge, this is the first demonstration that melanin pigmentation and plumage-based status badges are related to the competitive history of individuals during feather development. By coupling badge size directly with aggressive experiences during molt, birds can use their status signal to honestly indicate their likelihood of winning agonistic encounters throughout the year. 相似文献
6.
In breeding plumage, the African male red-shouldered widowbirds (Euplectes axillaris) are black except for red carotenoid-based epaulets ('shoulder patches'), similar to the well-studied American red-winged blackbirds (Agelaius phoeniceus). To experimentally test the signal function of the red epaulets in male red-shouldered widowbirds, we manipulated epaulet colour and size (within natural variation), and observed the effects in two competitive contexts. First, in captivity, unfamiliar males with epaulets of different size or redness were staged in dyadic contests over food. Only epaulet manipulations significantly affected contest outcome; red epaulet males out-competed orange and control males, which in turn dominated blackened (no epaulet) males. Epaulet size manipulations had particularly strong effects; enlarged epaulet males vigorously defeated smaller epaulet males within colour treatments, whereas the independent effect of 'redness' (i.e., within size treatments) was much weaker. Second, in a field experiment, epaulets were manipulated prior to territory establishment. Males with enlarged epaulets acquired territories, whereas most males with blackened or reduced signals failed to obtain territories. Furthermore, among the territorial males, birds with enlarged epaulets defended larger territories and spent less time in boundary signalling, yet they received fewer intrusions from conspecifics. In contrast, epaulet manipulations had no effect on either female visitation rates or subsequent female settlement. These results concur with recent studies and suggest that the carotenoid-based epaulets of red-shouldered widowbirds are status signals, sexually selected through male contest competition for territories. 相似文献
7.
The effects of preen oils and soiling on the UV–visible reflectance of carotenoid-pigmented feathers
Lorenzo Pérez-Rodríguez Francois Mougeot Gary R. Bortolotti 《Behavioral ecology and sociobiology》2011,65(7):1425-1435
Plumage coloration, particularly when carotenoid-based, is important in social signaling in birds. Although feather color
is a relatively stable trait, individuals may modify it with “cosmetic” substances such as preen oils. In addition, dirt accumulation
may influence plumage coloration and further affect signal perception by receivers. Here, we analyze the separate potential
effects of preen oils and soil accumulation on the reflectance properties of carotenoid-pigmented feathers across the visual
range of most bird species, which includes the ultraviolet (UV). Using the yellow portion of tail feathers of Bohemian waxwings
(Bombycilla garrulus), we performed two separate experiments where: (a) preen oils and/or soil were removed, or (b) preen oils (from black-billed
magpies Pica pica or eagle owls Bubo bubo) were added. Preen oil addition reduced brightness but increased UV hue and yellow chroma. UV chroma was reduced by the addition
of magpie (but not owl) preen oil. Soil accumulation had little effect on plumage reflectance in the UV range but significantly
reduced yellow chroma. According to models of avian vision, both of these effects are detectable by birds and biologically
meaningful when compared with natural variation between the sexes and age classes. We conclude that preen oil and soil accumulation
can significantly affect the UV–visible reflectance of carotenoid-based plumages. As such traits typically advertise individual
quality, preening and soiling have the potential to modify the information content of carotenoid-based plumage traits and
how these signals are perceived by receivers. 相似文献
8.
Pierrick Blanchard Rodolphe Sabatier Hervé Fritz 《Behavioral ecology and sociobiology》2008,62(12):1863-1868
Theory predicts that individuals at the periphery of a group should be at higher risk than their more central conspecifics
since they would be the first to be encountered by an approaching terrestrial predator. As a result, it is expected that peripheral
individuals display higher vigilance levels. However, the role of conspecifics in this “edge effect” may have been previously
overlooked, and taking into account the possible role of within-group competition is needed. Vigilance behavior in relation
to within-group spatial position was studied in impalas (Aepyceros melampus) feeding on standardized patches. We also controlled for food distribution in order to accurately define a “central” as opposed
to a “peripheral” position. Our data clearly supported an edge effect, with peripheral individuals spending more time vigilant
than their central conspecifics. Data on social interactions suggest that it was easier for a foraging individual to defend
its feeding patch with its head lowered, and that more interactions occurred at the center of the group. Together, these results
indicate that central foragers may reduce their vigilance rates in response to increased competition. Disentangling how the
effects of competition and predation risk contribute to the edge effect requires further investigations. 相似文献
9.
Joel W. McGlothlin Deborah L. Duffy Jessica L. Henry-Freeman Ellen D. Ketterson 《Behavioral ecology and sociobiology》2007,61(9):1391-1399
Sexually selected traits that act as signals of quality often display some degree of condition dependence. In birds, condition
dependence of ornamental plumage is often mediated by production costs related to acquisition or allocation of dietary resources.
White plumage ornaments, however, have often been assumed to be inexpensive because their production requires neither pigment
nor specialized feather structure. In male dark-eyed juncos (Junco hyemalis), the size of a white patch on the tail contributes to attractiveness and mating success. Using captive males, we examined
the effects of diet quality on the size and brightness of the tail-white patch. After removing four tail feathers to induce
replacement, we maintained subjects on a subsistence (low-protein) or enriched (high-protein) diet while induced feathers
grew. Birds that received an enriched diet grew their feathers more quickly and grew larger, brighter white patches. Feather
growth rate was positively correlated with the increase in the size of the tail-white patch, a relationship that was stronger
in the subsistence diet group. However, within diet treatments, faster-grown feathers were slightly duller. Taken together,
these results suggest that variation in diet quality may lead to condition-dependent expression of tail white and that condition
dependence may be stronger in more stressful environments. We suggest a mechanism by which increased feather growth rate may
lead to an increase in the size of the tail-white patch and discuss potential trade-offs between signal size and brightness. 相似文献
10.
Sex-specific nest defense in house sparrows (Passer domesticus) varies with badge size of males 总被引:2,自引:0,他引:2
Heinz-Ulrich Reyer Wiltrud Fischer Pascale Steck Thomas Nabulon Philip Kessler 《Behavioral ecology and sociobiology》1998,42(2):93-99
According to indicator models of sexual selection, females can benefit from choosing males with above average epigamic traits,
but empirical evidence for such benefits is scarce. Here, we report results from an experiment with 29 pairs of house sparrows
(Passer domesticus) where the intensity of nest defense against a mounted mustelid predator was related to the size of the black throat and
breast patch (“badge”) in males. Using principal components analysis (PCA), original response variables of both sexes were
reduced to two factors: “Approach” to the predator and “Distant warning”. “Approach”, the more risky behavior, increased from
small- through medium- to large-badged males and decreased in their females. Since large-badged males have a higher certainty
of paternity (i.e. greater benefits from defense) and may be older and more experienced (i.e. incur lower costs), the most
likely explanation for male defense intensity increasing with badge size is an improving benefit/cost ratio. The resulting
optimal response of their females and evolutionarily stable participation in joint parental care is illustrated by a graphical
model. It shows that females would, indeed, benefit directly from choosing large-badged males. This, however, is no proof
of a direct evolutionary tie between badge size and paternal behavior, as assumed by indicator models of sexual selection.
It may simply represent a spurious relationship, originating from the correlation of badge size and defense with confidence
of paternity.
Received: 22 September 1997 / Accepted after revision: 3 November 1997 相似文献
11.
Alice Rémy Arnaud Grégoire Philippe Perret Claire Doutrelant 《Behavioral ecology and sociobiology》2010,64(11):1839-1847
Badges of status, usually color patches, are hypothesized to serve as important signals within natural populations by communicating
an individual’s fighting ability or aggressiveness before an interaction ever takes place. These signals, which may evolve
via sexual and/or social selection, mediate intra-specific competition by influencing the outcome or escalation of contests
between individuals. The last 10 years saw the rise of interest in the role of ultraviolet (UV)-based coloration in intra-sexual
communication. However, the rare experimental studies that tested this hypothesis found opposite results, which may originate
from the different methodological procedures used to assess the badge of status theory. We present here the results of an
experiment testing whether male blue tits (Cyanistes caeruleus) respond differently to unfamiliar conspecifics presenting contrasted UV crest coloration. In an aviary, we simultaneously
presented two caged blue tits with enhanced (UV+) or reduced (UV−) crest coloration to a focal bird. We found that focal males
acted more aggressively towards the UV− males than UV+ males. In addition, focal males fed more often close to males that
were similar in brightness or duller than themselves. We conclude that, in blue tits, UV blue crest coloration affects both
social and aggressive responses towards unfamiliar individuals, and thus it has some properties of a badge of status. 相似文献
12.
Arnaud Da Silva Valentijn van den Brink Guillaume Emaresi Ester Luzio Pierre Bize Amélie N. Dreiss Alexandre Roulin 《Behavioral ecology and sociobiology》2013,67(7):1041-1052
Nest and territory defence are risky and potentially dangerous behaviours. If the resolution of life history trade-offs differs between individuals, the level of defence may also vary among individuals. Because melanin-based colour traits can be associated with life history strategies, differently coloured individuals may display different nest and territory defence strategies. We investigated this issue in the colour polymorphic tawny owl (Strix aluco) for which plumage varies from dark to light reddish melanic. Accordingly, we found that (1) our presence induced a greater response (flying around) from dark-coloured than light-coloured females and (2) dark reddish males suffered lower nest predation rates than light-coloured males. In experimentally enlarged broods, the probability that females reacted after we played back the hoot calls of a stranger male was higher if these females were lighter reddish; the opposite pattern was found in experimentally reduced broods with dark parents being more reactive than light parents. Finally, darker females alarmed more frequently when paired with a light than with a dark male, suggesting that partners adjust their behaviour to each other. We also tested whether colouration is used as a signal by conspecifics to adjust the level of their defensive behaviour. Accordingly, breeding females responded more vigorously to a dark than a light reddish stuffed tawny owl placed beside their nest. We conclude that melanin-based colouration is a signal of alternative nest and territory defence behaviour that depends on ecological factors. 相似文献
13.
Sjouke A. Kingma István Szentirmai Tamás Székely Veronika Bókony Maarten Bleeker András Liker Jan Komdeur 《Behavioral ecology and sociobiology》2008,62(8):1277-1288
Melanin-based ornaments are often involved in signaling aggression and dominance, and their role in sexual selection is increasingly
recognized. We investigated the functions of a melanin-based plumage ornament (facial ‘mask’) in male Eurasian penduline tits
Remiz pendulinus in the contexts of male–male aggression, mating success, and parental care. The penduline tit is a passerine bird with a
unique mating system in which both sexes may mate with several mates in a breeding season, and one (or both) parent deserts
the clutch. Our study revealed that mask size of males is more likely an honest signal used by females in their mate choice
decisions than a trait involved in male–male competition. First, mask size increased with both age and body condition, indicating
that the mask may signal male quality. Second, males with larger masks paired more quickly and had more mates over the breeding
season than males with smaller masks. Third, we found no evidence that male mask size signals male–male aggression or dominance
during competitive encounters. The increased mating success of large-masked males, however, did not translate into higher
reproductive success, as nestling survival decreased with mask size. Therefore, we conclude that there is either no directional
selection on male mask size or males with larger masks receive indirect, long-term benefits. 相似文献
14.
In an agonistic interaction, the assessment of the probable outcome of future encounters with the same individuals may be the best way of decreasing costs of fighting, but this may only be accomplished if animals are able to recognize individual conspecifics. We staged encounters between male lizards, Podarcis hispanica, to examine whether odoriferous cues are involved in rival recognition during agonistic interactions. We experimentally manipulated the odour of intruding males, creating familiar males with their own odour or bearing odours of unfamiliar males, and unfamiliar males bearing unfamiliar odours or odours of familiar males. The results showed that when familiar males were impregnated with scents from unfamiliar males, they elicited an aggressive response by resident unmanipulated males similar to that observed for a new unfamiliar male with unfamiliar odour. This suggests that resident males were unable to recognize familiar males when their own scents were removed. In contrast, responding males were less aggressive towards familiar males impregnated with their own odour and towards unfamiliar males impregnated with scents of familiar males, suggesting that when two males have already interacted, their scents become familiar for both males, and that the detection in successive encounters of the familiar scent suffices to reduce the aggressive response of territorial males. Therefore, recognition mechanisms based on chemical cues during agonistic encounters may contribute to reducing the intensity and the costs of fighting in P. hispanica and may play an important role in the organization of their social system. 相似文献
15.
Maria I. Sandell 《Behavioral ecology and sociobiology》2007,62(2):255-262
In the European starling, Sturnus vulgaris, optimal mating systems differ between males and females. Males gain from polygyny, whereas monogamy increases female fitness.
The cost of polygyny to females lead to intense female–female competition, and it has previously been shown that the intensity
of female aggression during the pre-breeding period can predict the realised mating system. The physiological regulation of
such female aggression in starlings is not yet known. This study examines the role of testosterone in mediating aggressive
behaviours involved in intra-specific reproductive competition in female starlings. Testosterone levels were experimentally
elevated with testosterone implants in females during the pre-laying period. To simulate a situation in which an additional
female tried to mate with the focal female’s mate, a caged female was presented close to a nest-site to which the male could
attract a secondary female. Testosterone was significantly related to several behaviours involved in female–female interactions.
Females with testosterone implants spent significantly more time close to the caged female and produced more song bouts than
control females. In contrast, male behaviour was unrelated to the experimental status of the mate. Females mated to males
that attracted a secondary female were less aggressive towards the caged female than those that remained monogamously mated.
The effect of exogenous testosterone in this study indicates that androgens may mediate social behaviours in female starlings
during the breeding season. 相似文献
16.
Many animals use multiple signals in sexual communication, but our understanding of the interactions between multiple signals,
particularly in inexperienced breeders, is limited. In birds, delayed plumage maturation (DPM) is well documented; young birds
appear duller than adults, despite reaching sexual maturity. Age-related changes in song structure are also common in songbirds,
though the extent to which songs of yearling males differ from those of adults (delayed song maturation, DSM) and its prevalence
in species with DPM is unknown. We tested for DSM in the mate-attraction (repeat) song of a species with dramatic DPM, the
American redstart (Setophaga ruticilla). Repeat song structure of territorial yearling and adult males differed significantly, based on discriminant analysis of
nine non-collinear song features. Combined with previous evidence of delayed maturation in territorial (serial) song, we provide
the first evidence for DSM in different song types used in different behavioral contexts during the breeding season of a migratory
songbird. Within adults, variation in repeat song was associated with pairing, earlier onset of breeding, and number of offspring
sired, suggesting a potential benefit for expressing more adult-like song. We found no relationship between the expression
of adult-like repeat song and plumage in either age class. These results indicate that delayed maturation of repeat song in
yearling redstarts is not due to a generalized delay in signal development, and suggest further work is needed to determine
whether mate attraction (for both yearling and adult males) provides greater pressure to sound more “adult-like” than to look
more “adult-like”. 相似文献
17.
Vertebrate eggs contain maternal steroid hormones in their yolks; and in avian species the concentration of these steroids vary within and among clutches. The organizational actions of these variable doses of maternal steroids in the avian egg, analogous to those regulating the development of sexually dimorphic traits, are little explored. In this study, we examined the organizational effects of yolk testosterone in the house sparrow,
Passer domesticus, a sexually dichromatic passerine bird in which males are characterized by the presence of a throat patch or badge of black feathers that varies in size among males. We injected a physiological dose of testosterone or vehicle into eggs in the field, removed nestlings, and hand-raised them in the laboratory. At 5 months of age, we investigated treatment effects on plumage and behavior. Males that hatched from testosterone-injected eggs developed a larger badge than males that hatched from vehicle-injected (control) eggs. However, testosterone did not induce the expression of a badge in females. In staged dyadic encounters, both males and females hatched from testosterone-injected eggs were more successful at obtaining and defending a food source than individuals of the same sex hatched from control eggs. The results suggest that variable concentrations of maternal testosterone in the eggs of the house sparrow organize the expression of a plumage trait in males and behavior in both sexes.Communicated by J. Graves 相似文献
18.
Matteo Griggio Francisco Valera Alejandro Casas-Crivillé Herbert Hoi Andrés Barbosa 《Behavioral ecology and sociobiology》2011,65(4):655-664
In birds, colourful and elaborate feathers are important traits in mate choice. Distinct tail white patches are present in
many species of birds, but they remain little studied. Tail markings may indeed have a signal function because in many species
males spread the tail offering a good view of these markings to females during courtship behaviour. Here, we investigated
whether white tail spots in male rock sparrow, Petronia petronia, play a role in mate choice. In a free-living population of rock sparrows, we found a reduction in white tail spots size
as the breeding season progressed due to abrasion, which was expected if tail spots act as a reliable quality indicator (i.e.
a handicap). The same reduction was found under captive conditions, and males in worse condition (individuals that lost more
weight) abraded a bigger part of white. This suggests that white tail markings are an indicator of male quality. In captivity,
we measured female preference for males differing in white patch size in a mate choice experiment. The experimental reduction
of the size of the males’ white spots resulted in a lower sexual interest by females. During courtship display, male rock
sparrow shows a yellow breast patch (a carotenoid-based, sexually selected ornament) together with the white spots in the
tail. The sizes of these two traits are positively correlated, but only the abraded white area in the tail correlates with
a surrogate of individual quality (lost of weight). In conclusion, we can assert that the size of the white spots is preferred
by female rock sparrows and it is a part of a multiple signal system. 相似文献
19.
Hamilton and Zuk proposed that bright plumage in birds indicates genetic resistance to parasites, and that by selecting brighter
males as mates, females can increase their offspring’s fitness due to this inherited resistance. The theory predicts a negative
relationship between parasite load and plumage brightness in males. We used Sindbis virus clearance rate after an experimental
infection to quantify parasite resistance in male greenfinches (Carduelis chloris) and related variation in clearance rate with variation in male plumage brightness. We found that certain aspects of brightness
of the male plumage (i.e. tail-patch area) could be used to predict the virus infection clearance rate. Wing brightness was
uninformative of virus clearance rate, but revealed age class. We found no clear relationship between antibody production
rate and virus clearance rate or total viraemia. However, males with large tail patches tended to have a higher antibody production
rate. The results suggest that the size of the male tail patch may function as an indicator of an individual male’s ability
to resist parasite infections, thus supporting the Hamilton-Zuk theory for a novel taxon of parasites, a virus.
Received: 11 November 1999 / Received in revised form: 13 March 2000 / Accepted: 1 April 2000 相似文献
20.
The adaptive significance of male subadult plumage in purple martins: plumage dyeing experiments 总被引:1,自引:0,他引:1
Bridget J. Stutchbury 《Behavioral ecology and sociobiology》1991,29(4):297-306
Summary I tested two hypotheses for the adaptive significance of subadult plumage in male purple martins (Progne subis) : the female mimicry and subordinance signaling hypotheses. Subadult males were at a competitive disadvantage in obtaining territories, as they arrived later in the spring than adult males. Contrary to the predictions of both hypotheses, adult male territory owners were not less aggressive toward subadult male than adult male intruders. The subadult plumage was not effective in mimicking females, as adult male owners were significantly more aggressive toward subadult male than female intruders. Summer adaptation hypotheses predict that young males in subadult plumage are more successful in acquiring territories and mates than they would be with an adult plumage. I tested this prediction by dyeing the plumage of floater subadult males to mimic the appearance of adult males. In 13/17 paired experiments, dyed subadults obtained territories before control subadults. There was no difference in the time it took dyed and control males to attract a mate after they obtained a territory. These results suggest that the subadult plumage is not an advantage to young males in competing with adult males for breeding resources. In late winter, subadult males were growing mostly femalelike feathers on their underside, suggesting that the subadult plumage is not the result of a molt constraint. The subadult plumage could enhance survival of yearlings in winter roosts if it improves access to good roost sites or reduces the risk of predation. 相似文献