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41.
Summary. While many marine molluscs have been suggested to use aposematic coloration to avoid predation, few studies have tested the
ability of marine predators to learn to associate colors with distasteful prey. In field experiments, we tested the ability
of two populations of reef fishes to discriminate among red, yellow, and black artificial nudibranch models when one color
was paired with a feeding deterrent. We offered fishes (1) the models without any feeding deterrents, (2) the models with
a feeding deterrent coated onto one color, and (3) the models without deterrents again. If reef fishes learn to associate
colors with noxious prey, we expected the color paired with the feeding deterrent to be eaten less frequently in the final
assay than the initial assay. In both populations, fishes formed clear associations between color and feeding deterrence.
However, when the experiment was repeated in one population, changing the color paired with the feeding deterrent, fishes
did not form an association between color and feeding deterrence. In this case, prior learning may have affected subsequent
trials. Our study indicates that common colors of nudibranchs are recognizable by fishes and can be associated with noxious
prey.
Received 24 September 1998; accepted 18 December 1998. 相似文献
42.
Sibling aggression, hatching asynchrony, and nestling mortality in the black kite (Milvus migrans) 总被引:3,自引:0,他引:3
Javier Viñuela 《Behavioral ecology and sociobiology》1999,45(1):33-45
In siblicidal species, hatching asynchrony could act to reduce sibling rivalry or promote the death of last-hatched chicks.
The pattern of hatching asynchrony was experimentally altered in the black kite Milvus migrans. Hatching asynchrony in control broods was intermediate between those of experimentally synchronised and asynchronised broods.
Sibling aggression and wounds on the chicks were more commonly observed early in the nestling period and in synchronous nests.
Serious injuries were observed on last-hatched chicks in asynchronous nests, as were observations of intimidated or crushed
chicks. Sibling aggression was related to food abundance, but some chicks died at an early age in nests with abundant food
(cainism). Cainism was more commonly found in asynchronous nests. For species with facultative siblicide, moderate hatching
asynchrony could be a compromise between reducing sibling rivalry and avoiding large size differences between sibs that would
result in cainism. Female black kites preferentially fed the smallest chicks and exhibited behaviours to reduce sibling aggression,
contrary to observations in other siblicidal species. In a highly opportunistic forager such as the black kite, a strategy
may exist to protract the life of all the chicks in the brood, waiting for unpredictable situations of food overabundance.
This would induce the appearance of a parent-offspring conflict over brood reduction, reflected in the existence of a possible
anticipated response by some of the chicks (cainism) and in the appearance of special behaviours by the parents to selectively
feed smaller chicks or reduce sibling aggression. In this facultatively siblicidal species, cainism does not seem to be the
final stage of an evolutionary trend favouring the raising of high-quality chicks, but a manifestation of a parent-offspring
conflict over brood size.
Received: 9 March 1998 / Accepted after revision: 8 August 1998 相似文献
43.
Donald C. Dearborn 《Behavioral ecology and sociobiology》1998,43(4-5):259-270
Understanding the selective forces that limit the exaggeration of begging signals is a critical issue in understanding the
evolution of begging behavior. I studied the begging behavior of nestlings of the brown-headed cowbird (Molothrus ater), a brood parasite. In the nests of indigo buntings (Passerina cyanea), brown-headed cowbird nestlings received approximately twice as much food per hour than their host nestmates. I tested three
hypotheses for the mechanism by which cowbirds acquired more food than their bunting nestmates: the size advantage hypothesis,
the signal exaggeration hypothesis, and the novel begging behavior hypothesis. I found support for the hypotheses that cowbirds
acquire more food as a result of their larger body size, and due to the exaggeration of begging signals that are not dependent
on body size. I did not find support for the role of novel begging behaviors in cowbird food acquisition. These results suggest
that food acquisition by host chicks in unparasitized nests could be increased by the exaggeration of begging signals. Recent
work suggests that such exaggeration may be limited by the risk of nest predation, but further studies are needed.
Received: 12 December 1997 / Accepted after revision: 29 December 1997 相似文献
44.
In male willow ptarmigans, the relationship between qualitative differences between birds belonging to different intrapopulation groups and some individual features of male nuptial plumage has been revealed by studying banded birds. Thus, males that have changed their nesting site differ from those returning to the former site and bigamous males differ from monogamous in the number and size of dark spots amid the white plumage. The influence of the time of the onset of spring on the development of nuptial plumage is considered. 相似文献
45.
HR gas chromatographic PCB patterns in human/poultry fat tissue and hair/plumage in samples from a polluted region of Bela Krajina /Slovenia/ were investigated. The concentration of PCBs in human adipose tissue was found to be 9.62 μg/g in comparison to 0.67 μg/g in the adipose tissue of the non-exposed population, and in poultry fat 12.80 μg/g on a fat basis. The corresponding values in human hair and poultry plumage were 0.90 μg/g and 0.20 μg/g of original weight. The difference in PCB patterns between fat and hair can be attributed to the different routes of contamination (ingestion, air transport), to the time of exposure and physicochemical properties (octanol- water partition coefficients, Henry's law constants and the metabolism) of some individual congeners. Hair could be used for the assessment of ingestion of contaminated food and of the PCB levels in the air. In fat tissue PCB congeners with higher metabolic stability are enriched, whereas in hair PCB congeners with higher concentrations in air and with high octanol- water partition coefficients predominate. 相似文献
46.
Juliana Valencia Elena Solís Gabriele Sorci Carlos de la Cruz 《Behavioral ecology and sociobiology》2006,60(3):399-404
In cooperatively breeding species, helpers may contribute to the success of the brood by increasing the number of independent offspring, but also, they may affect offspring condition and, hence, their survival and recruitment into the breeding population. This second type of benefits is rarely included in theoretical models or assessed in field studies. Immune response is a good proxy of individual quality and fitness, and there is good evidence that the performance of the immune system of chicks during the nestling phase is related to their chances of survival and future reproduction. However, no study has so far explored whether helpers at the nest might contribute to enhance immune functioning of nestlings in species with a cooperative breeding system. Here we investigate this issue in the azure-winged magpie (Cyanopica cyanus) and found for the first time a positive correlation between the number of helpers at nest and the cell-mediated immune response of nestlings. This effect was not explained by a general improvement of body condition of chicks because it was independent of individual variation in body mass or tarsus length. Our results suggest that helping can have subtle effects on the quality of offspring that may influence their survival and future reproduction. 相似文献
47.
Commonly, female birds use the brightly coloured patches on males to choose the best-quality mates. Coloured wing patches, however, have received little attention or have been previously related to social behaviour (as a signal to recruit conspecific individuals at feeding patches) or foraging (to flush prey) contexts, rather than to sexual selection. Here we provide evidence that in siskins (Carduelis spinus), wing patches function in mate choice. Mate-choice experiments showed that females were attracted by the size of the yellow wing stripe of the male, but not by the size of its black bib, body size, general plumage brightness or age. Experiments on birds with manipulated yellow wing stripes showed that females were sensitive to the size of this colour patch, irrespective of other male qualities. The preference of female siskins for males with larger wing patches when searching for a mate may be explained by the relationship of this trait to foraging ability, which would ensure females good parental investment from the chosen male.Communicated by W.A. Searcy 相似文献
48.
Although evidence is accumulating on the adaptive function of female ornamentation, very little is known about maternal allocation
decisions involving sexual signaling and other reproductive functions. Blue egg coloration has been suggested as a sexually
selected signal of female quality to males, and some recent studies are in accordance with this hypothesis. Blue eggshell
coloration results from the deposition of biliverdin pigment by laying females, which is a potent antioxidant. Thus, egg pigmentation
should be costly in terms of antioxidants, an assumption of the signaling hypothesis that has not been tested yet. We induced
increased reproductive effort in a set of female pied flycatchers Ficedula hypoleuca through nest removal and measured egg pigmentation and plasma antioxidant levels in relation with a control group. Experimental
females showed a negative association between egg color and plasma antioxidant levels, while there was no relationship for
control birds. This supports that egg pigmentation is costly in terms of general antioxidant defenses and suggests a tradeoff
between the allocations to both traits. Furthermore, experimental females with more colorful eggs raised more fledglings,
especially when breeding early. Controls did not show a relationship between egg color and reproductive success. Females laying
more colorful eggs could have shifted their allocation decisions towards current reproduction, at the expense of their own
antioxidant defenses. Our results highlight that blue egg coloration is a life-history trait, subject to tradeoffs with other
attributes, and seems to be especially informative under harsh breeding conditions. 相似文献
49.
Susan L. Balenger L. Scott Johnson Brian S. Masters 《Behavioral ecology and sociobiology》2009,63(3):403-411
Ornamental traits are thought to evolve because they give individuals an advantage in securing multiple mates. Thus, the presence
of ornamentation among males in many monogamous bird species presents something of a conundrum. Under certain conditions,
extra-pair paternity can increase the variance in reproductive success among males, thus increasing the potential for sexual
selection to act. We addressed this possibility in the mountain bluebird (Sialia currucoides), a socially monogamous songbird in which males possess brilliant ultraviolet (UV)-blue plumage. Specifically, we asked whether
a male’s success at siring offspring within his own nest and within the nests of other males was related to his coloration.
In pairwise comparisons, males that sired extra-pair offspring were not more colorful than the males that they cuckolded.
However, males that sired at least one extra-pair offspring were, on average, brighter and more UV-blue than males that did
not sire extra-pair offspring. Brighter, more UV-blue males sired more offspring both with their own mate and tended to sire
more offspring with extra-pair mates and thus sired more offspring overall. Our results support the hypothesis that the brilliant
UV-blue ornamental plumage of male mountain bluebirds evolved at least in part because it provides males with an advantage
in fertilizing the eggs of multiple females. 相似文献
50.
Alexandre Roulin 《Die Naturwissenschaften》2009,96(3):375-382
Identifying the factors that mediate covariation between an ornament and other phenotypic attributes is important to determine
the signaling function of ornaments. Sign and magnitude of a covariation may vary across environments if the expression of
the ornament or of its linked genes regulating correlated phenotypes is condition-dependent. I investigated in the barn owl
Tyto alba whether sign and magnitude of covariation between body mass and two heritable melanin-based plumage ornaments change with
food supply, along the reproductive cycle and from the morning to the evening. Using a dataset of 1,848 measurements of body
mass in 336 breeding females, I found that females displaying large black spots were heavier than conspecifics with smaller
spots in the afternoon (i.e., a long time after the last feeding) but not in the morning (i.e., a short time after the last
feeding). This is consistent with the recently proposed hypothesis that eumelanin-based ornaments are associated with the
ability to maintain energy balance between food intake and energy expenditure. Thus, covariation between melanin-based coloration
and body mass can be detected only under specific conditions potentially explaining why it has been reported in only ten out
of 28 vertebrate species. The proposition that ornamented individuals achieve a higher fitness than drab conspecifics only
in specific environments should be tested for other ornaments. 相似文献