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1.
张志杰 《辽宁城乡环境科技》2006,26(1):29-30,33
目前测定空气中SO2主要采用甲醛吸收-副玫瑰苯胺分光光度法。该法操作比较严格,测试结果的准确度受诸多因素的影响。因此文中对这些影响因素进行了探讨,主要为试剂质量、显色温度和显色时间、溶液加入顺序、比色皿、空气采样器流量、采样温度、导气管的吸附等因素对测定结果的影响进行了探讨。 相似文献
2.
The phenetic structure of natural and urbanized populations of the terrestrial snail Cepaea vindobonensis has been studied with respect to polymorphism in the shell-band color and pattern. It is noted that C. vindobonensis snails populating different artificial habitats in the city of Nikolaev and its suburbs are characterized by a higher level of both intra-and interpopulation diversity with respect to the type of this polymorphism. In addition, urban populations show a very wide range of variation in the frequencies of particular morphs or their groups. Conversely, natural populations are characterized by a more uniform frequency structure with respect to polymorphism of the shell banding pattern. 相似文献
3.
José P. Veiga 《Behavioral ecology and sociobiology》1996,39(5):345-352
In many bird species the cryptic winter plumage is due to the presence of light feather tips that conceal conspicuous colorations.
The gradual abrasion of these tips that makes sexual traits visible has been interpreted as a strategy to improve mating success
(here referred as the permanent exhibition hypothesis). However, under some circumstances, the maintenance of a full plumage
that facultatively enables the bird to exhibit or cover aggression-inducing traits has proved to be advantageous (the coverable
badge hypothesis). In a population of house sparrows where black throat patches (here called badges) are used in intrasexual
competition, the degree of abrasion of dull feather tips that conceal bright colour early in the breeding season correlated
neither with badge size nor with traits indicating morphology and body condition. These results are only in accordance with
predictions of the coverable badge hypothesis. In 1992 experimental clipping of badge feather tips, which forced permanent
exposure of badges, negatively affected birds with the largest badges in terms of nest acquisition, but an opposite trend
was indicated for birds with the smallest badges. In 1993, when more novel birds in the study area were competing for nesting
sites than in 1992, only badge size, but not the experimental manipulation, affected nesting success. These results suggest
that the loss of the ability to conceal badges was disadvantageous, and more so if most competing individuals had already
been resident in the colony in previous years and the larger their badges were. There is a striking contrast between the results
reported for this study population, where badges mainly signal fighting ability, and those reported for another house sparrow
population, where badges are mainly used in mate choice. In this last population, tip abrasion is advantageous for dominant
individuals showing the largest badges. This suggests that the trade-off between conserving versus wearing off the feathers
that conceal ornaments could have different optimal resolutions depending on the relative importance of inter and intrasexual
selection on indicator traits.
Received: 29 September 1995/Accepted after revision: 14 July 1996 相似文献
4.
Frank Götmark 《Behavioral ecology and sociobiology》1997,40(1):41-49
Conspicuous color patterns in birds may lead to increased risk of predation. Alternatively, bright birds may be aposematic
or unprofitable prey, which leads to decreased predation. During four autumns, I examined whether the black-and-white plumage
of (stuffed) magpies Pica pica increases or reduces the risk of attack by migrating goshawks Accipiter gentilis. Attack risk was higher for normal magpies than for cryptic, brown magpies whether the mounts were placed near one another
or far apart. However, the brown magpie may have been avoided because of its novelty. For magpies and cryptic jays Garrulus glandarius exposed together, the attack risk was similar. In 2 years, magpie and jay mounts were also exposed far apart. In 1994, with
an invasion of migrating jays, attack risk was much higher for jays than for magpies. In 1995, with a normal density of jays,
hawks attacked the magpies more often. The results demonstrate frequency-dependent prey selection by goshawks, which would
influence any predation cost of bright plumage. The attacks on normally colored magpie mounts suggest that magpies are not
aposematic. Trials with photographs and human observers indicated that normal magpies were somewhat easier to detect than
jays. The plumage of the magpie possibly increases the risk of predation, but may be favoured by sexual or social selection.
Received: 18 January 1996 / Accepted after revision: 6 October 1996 相似文献
5.
Caroline Isaksson Tobias Uller Staffan Andersson 《Behavioral ecology and sociobiology》2006,60(4):556-562
Carotenoid pigments have attracted much interest in behavioural and evolutionary ecology because of their dual function in immune physiology and as color signals. In vertebrates, carotenoids must ultimately be obtained from the diet, and the mechanisms and magnitude of this environmental dependence are central for understanding carotenoid signal functions and evolution. In the present cross-fostering experiment with great tits Parus major, we investigate pre- and postnatal parental effects (egg yolk carotenoids, parental coloration) on nestling size and carotenoid coloration, using HPLC analysis of egg yolk carotenoids, and a reflectance-based measure of ‘chroma’ that reflects the plumage pigment concentration. Both rearing environment and origin influenced offspring size and plumage chroma. Maternal allocation of carotenoids to eggs had a weak positive effect on nestling plumage chroma, whereas we found no prenatal maternal effects (egg size or yolk carotenoid concentration) on size. Nestling plumage chroma was also significantly predicted by the chroma of the rearing father, but not by the color of the rearing mother or either of the original (genetical) parents. Thus, both prenatal maternal effects and postnatal paternal effects influence the carotenoid-based plumage coloration of nestling great tits. Future studies will reveal if parental effects have long-term consequences for plumage development and associated fitness components. 相似文献
6.
Jesús M. Avilés Bård G. Stokke Arne Moksnes Eivin Røskaft Anders P. Møller 《Behavioral ecology and sociobiology》2007,61(3):475-485
The outer layer of the eggshell in birds is in many cases covered by pigments that are assumed to be genetically determined traits with a negligible environmental component. To test the hypothesis that spring environmental conditions (i.e., temperature and rainfall) may affect bird egg pigmentation, we measured by spectrophotometry and photography egg coloration and spottiness on reed warbler (Acrocephalus scirpaceus L.) clutches parasitized by the common cuckoo (Cuculus canorus L.) collected over a period of 24 years and preserved in the Zoological Museum, Copenhagen, Denmark. In addition, we investigated whether spring environmental conditions may influence the coevolutionary relationship between the cuckoo and its host via changes in cuckoo–host egg matching. Generalized mixed models revealed that reed warbler eggs were more brilliant in those springs with a higher rainfall and tended to be bluer and greener in springs with a lower relative temperature. On the other hand, cuckoo eggs were bluer and greener in springs with a higher rainfall. Cuckoo–host egg matching in blue-greenness and spottiness was better in springs with a higher rainfall. These results provide support for the existence of an environmental component on bird egg coloration and suggest that environmental factors may potentially affect the outcome of important features of the arms race between cuckoos and reed warblers. 相似文献
7.
Testis size variation in the greenfinch Carduelis chloris : relevance for some recent models of sexual selection 总被引:3,自引:0,他引:3
Interspecific evidence that testis size responds to selection caused by sperm competition has been obtained from many taxa. However, little is known about the sources of intraspecific variation in testis size, although such variation may have functional significance. Variation in testis size and asymmetry was studied within and between eight geographically separated (and genetically differentiated) populations of greenfinches Carduelis chloris. The relationships between testis size and plumage brightness (degree of yellowness) and the prevalence of haematozoan infections were also investigated in three of these populations, as they related to the predictions of the immunocompetence handicap hypothesis, and Møller's hypothesis relating directional testis asymmetry to phenotypic quality. There were large differences between populations in testis size, with males from northern populations having larger testes than those from southern populations. Within populations, large testes were associated with larger body size and greater age. When the influence of these factors was removed statistically, males with large testes were more likely to be infected with haematozoan parasites, and had brighter yellow plumage. No evidence was found that directional asymmetry in testis size was related to either of these measures of phenotypic quality. These results are consistent with the hypothesis that males with large testes, while signalling higher phenotypic quality as revealed by increased plumage brightness, also pay a cost in terms of reduced immunocompetence, revealed by the increased probability of infection in these males. That these patterns were similar in three different populations adds further strength to these conclusions. Our results suggest that studying the sources of variation in testis size among individuals can reveal interesting processes in sexual selection. 相似文献
8.
Although many avian eggs appear to be cryptically colored, many species also lay vibrant blue green eggs. This seemingly conspicuous
coloration has puzzled biologists since Wallace, as natural selection should favor reduced egg visibility to minimize predation
pressure. The sexual signaling hypothesis posits that blue green egg coloration serves as a signal of female quality and that
males exert post-mating sexual selection on this trait by investing more in the nests of females laying more intensely blue
green eggs. This hypothesis has received mixed support to date, and most previous studies have been conducted in cavity-nesting
species where male evaluation of his partner’s egg coloration, relative to that of other females, may be somewhat limited.
In this study, we test the sexual signaling hypothesis in colonially nesting ring-billed gulls (Larus delawarensis) where males have ample opportunity to assess their mate’s egg coloration relative to that of other females. We used correlational
data and an experimental manipulation to test four assumptions and predictions of the sexual signaling hypothesis: (1) blue
green pigmentation should be limiting to females; (2) extent of blue green egg coloration should relate to female quality;
(3) extent of blue green egg coloration should relate to offspring quality; and (4) males should provide more care to clutches
with higher blue green chroma. Our data provide little support for these predictions of the sexual signaling hypothesis in
ring-billed gulls. In light of this and other empirical data, we encourage future studies to consider additional hypotheses
for the evolution of blue green egg coloration. 相似文献
9.
A. Roulin J. Gasparini P. Bize M. Ritschard H. Richner 《Behavioral ecology and sociobiology》2008,62(4):507-519
One hypothesis for the maintenance of genetic variation states that alternative genotypes are adapted to different environmental
conditions (i.e., genotype-by-environment interaction G×E) that vary in space and time. Although G×E has been demonstrated
for morphological traits, little evidence has been given whether these G×E are associated with traits used as signal in mate
choice. In three wild bird species, we investigated whether the degree of melanin-based coloration, a heritable trait, covaries
with nestling growth rate in rich and poor environments. Variation in the degree of reddish-brown phaeomelanism is pronounced
in the barn owl (Tyto alba) and tawny owl (Strix aluco), and variation in black eumelanism in the barn owl and Alpine swift (Apus melba). Melanin-based coloration has been shown to be a criterion in mate choice in the barn owl. We cross-fostered hatchlings
to test whether nestlings sired by parents displaying melanin-based colorations to different extent exhibit alternative growth
trajectories when raised by foster parents in poor (experimentally enlarged broods) and rich (experimentally reduced broods)
environments. With respect to phaeomelanism, barn owl and tawny owl offspring sired by redder parents grew more rapidly in
body mass only in experimentally reduced broods. With respect to eumelanism, Alpine swift offspring of darker fathers grew
their wings more rapidly only in experimentally enlarged broods, a difference that was not detected in reduced broods. These
interactions between parental melanism and offspring growth rate indicate that individuals display substantial plasticity
in response to the rearing environment which is associated with the degree of melanism: at least with respect to nestling
growth, phaeomelanic and eumelanic individuals are best adapted to rich and poor environments, respectively. It now remains
to be investigated why eumelanism and phaeomelanism have a different signaling function and what the lifelong consequences
of these melanism-dependent allocation strategies are. This is important to fully appraise the role played by environmental
heterogeneity in maintaining variation in the degree of melanin-based coloration. 相似文献
10.
Martin Stevens Claire L Stubbins Chloe J Hardman 《Behavioral ecology and sociobiology》2008,62(11):1787-1793
Animals utilise various strategies to reduce the risk of predation, including camouflage, warning colours and mimicry, and
many of these protective signals promote avoidance behaviour in predators. For example, various species possess paired circular
‘eyespots’, which startle or intimidate predators, preventing or halting an attack. However, little is known of how the efficacy
of such signals relates to the context in which they are found, and no studies have tested the relative effectiveness of anti-predator
signals when on otherwise camouflaged and conspicuous prey. We find that the protective value of conspicuous wing spots, placed
on artificial moth-like targets presented to wild birds in the field, is strongly affected by the attributes of the prey ‘animal’
on which they are found. Wing spots reduced predation when on conspicuous prey but were rendered ineffective when on otherwise
camouflaged targets, indeed they increased the risk of predation compared to non-marked camouflaged controls. These results
demonstrate how different anti-predator strategies may interact, and that protective signals can switch from being beneficial
to costly under different contexts. 相似文献