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341.
Leg ornamentation and the efficacy of courtship display in four species of wolf spider (Araneae: Lycosidae) 总被引:1,自引:1,他引:0
This study used both correlative and experimental video playback methods to test the hypothesis that the secondary sexual
traits of male wolf spiders act to increase the efficacy of visual courtship displays. Direct observations of courtship of
several lycosid genera and a review of the literature revealed a significant association between ornamentation and visual
courtship displays. This suggests that the ornamentation may be playing the role of amplifier for a visual display. To test
this hypothesis, male courtship behaviors of four Schizocosa species were experimentally manipulated using video-imaging techniques. Females of species with non-visually displaying,
non-ornamented males (Schizocosa duplex and S. uetzi) did not increase in frequency of receptivity when tufts were added to conspecific males. In a species with a visual display
and foreleg pigmentation (S. stridulans), the addition of foreleg tufts increased female receptivity. In a tufted species (S. crassipes), females tended to decrease their receptivity when male ornamentation was completely removed. In visually displaying species,
ornamentation acts to increase female receptivity, supporting its role as an amplifier of a visual display.
Received: 29 December 1997 / Received in revised form: 23 October 1999 / Accepted: 13 December 1999 相似文献
342.
M. Itzkowitz M. J. Draud J. L. Barnes M. Haley 《Behavioral ecology and sociobiology》1998,42(3):149-155
Male beaugregory damselfish (Stegastes leucostictus) spent more time courting larger females in both two-choice and single presentations. Female size was significantly correlated
with gonad weight. We also verified that female fecundity was extremely variable within a natural population. We found that
male reproductive success was highly correlated with both clutch size and clutch number. However, clutch size was not significantly
correlated with clutch number, indicating that males that received larger clutches did not receive more egg clutches. Furthermore,
there was no difference between the number of offspring produced by males that mated with the largest females and by males
that mated with the most females. Thus, although males preferred larger females, males produced similar numbers of offspring
by mating with large females or mating with many females.
Received: 7 March 1997 / Accepted after revision: 1 November 1997 相似文献
343.
Astrid M. Heiling 《Behavioral ecology and sociobiology》1999,46(1):43-49
The nocturnal orb-web spider Larinioides sclopetarius lives near water and frequently builds webs on bridges. In Vienna, Austria, this species is particularly abundant along the
artificially lit handrails of a footbridge. Fewer individuals placed their webs on structurally identical but unlit handrails
of the same footbridge. A census of the potential prey available to the spiders and the actual prey captured in the webs revealed
that insect activity was significantly greater and consequently webs captured significantly more prey in the lit habitat compared
to the unlit habitat. A laboratory experiment showed that adult female spiders actively choose artificially lit sites for
web construction. Furthermore, this behaviour appears to be genetically predetermined rather than learned, as laboratory-reared
individuals which had previously never foraged in artificial light exhibited the same preference. This orb-web spider seems
to have evolved a foraging behaviour that exploits the attraction of insects to artificial lights.
Received: 8 June 1998 / Received in revised form: 18 January 1999 / Accepted: 19 January 1999 相似文献
344.
The criteria as laid out by the International Union for the Conservation of Nature (IUCN) Red List are the gold standard by which the extinction risk of a species is assessed and where appropriate biological extinctions are declared. However, unlike all other categories, the category of extinct lacks a quantitative framework for assigning this category. Given its subjective nature, we surveyed expert assessors working on a diversity of taxa to explore the attributes they used to declare a species extinct. Using a choice experiment approach, we surveyed 674 experts from the IUCN Species Survival Commission specialist groups and taskforces. Data availability, time from the last sighting, detectability, habitat availability, and population decline were all important attributes favored by assessors when inferring extinction. Respondents with red-listing experience assigned more importance to the attributes data availability, time from the last sighting, and detectability when considering a species extinction, whereas those respondents working with well-known taxa gave more importance to the time from the last sighting. Respondents with no red-listing experience and those working with more well-known taxa (i.e., mammals and birds) were overall less likely to consider species extinct. Our findings on the importance assessors place on attributes used to declare a species extinct provide a basis for informing the development of specific criteria for more accurately assessing species extinctions. 相似文献
345.
有机热载体锅炉安全选用及安装质量探讨 总被引:1,自引:0,他引:1
通过有机热载体炉的工作原理分析,介绍了锅炉及其系统中循环泵和膨胀器的选用及安装的要求,并对有机热载体炉安装过程中质量的控制提出了一些要求. 相似文献
346.
D. J. Green H. L. Osmond M. C. Double A. Cockburn 《Behavioral ecology and sociobiology》2000,48(6):438-446
Empirical and theoretical studies have only recently begun to examine how females use complex multi-component displays when
selecting mates. Superb fairy-wrens are well suited to the study of female choice because females have control over extra-group
paternity and cuckold their mates at high rates, while males possess a variety of sexually selected traits. Available evidence
suggests that females base their extra-group mate choice on the timing of male moult into breeding plumage or the onset of
display. However, males continue to perform elaborate displays throughout the season, and direct most displays to females
during their fertile period. We therefore conducted focal observations on fertile females to quantify the frequency of male
display and used microsatellite genotyping to compare the role of display rate during the breeding season and the timing of
male moult on female mate choice. We show that the addition of data on male display rate does not improve our ability to predict
which males obtain extra-group paternity. The timing of male moult into breeding plumage remains the only predictor of male
extra-group reproductive success. Nevertheless, we found that males displayed more to females that were unable to select extra-group
mates on the basis of the timing of moult or the onset of display. This raises the possibility that there are circumstances
when females use display rate to discriminate between potential extra-group sires. Overall this study supports the theoretical
prediction that females are more likely to base their mate choice on reliable indicators of male quality such as fixed morphological
traits and displays of endurance, in this case an early moult into breeding plumage and the performance of an elaborate display
during the winter, than a flexible behavioural trait such as display rate during the breeding season.
Received: 26 January 2000 / Revised: 1 August 2000 / Accepted: 26 August 2000 相似文献
347.
结合常州市环境噪声自动监测系统的建设和运行,建议子站位置合理避开非正常干扰因素,有效进行机箱的降温和安全防护,同时对数据比对监测等方面进行探讨,对各地陆续开展的噪声自动监测系统建设有所帮助。 相似文献
348.
Rinaldo Brau Antonello E. Scorcu Laura Vici 《Journal of Environmental Planning and Management》2009,52(1):25-42
This paper assesses the appeal of potential interventions on the tourism offer of Rimini, a popular Italian seaside holiday destination, by means of a choice modelling analysis. Tourism can be viewed as a composite good, its overall utility depending on the arrangement of the component characteristics. The discrete choice experiments here incorporate as attributes a number of possible changes to current tourist activities (the subject of public debate), including them in hypothetical alternative holiday packages. The conditional logit analysis indicates that tourists show lesser preference for interventions aimed at protecting the environmental integrity of the beach and greater preference for those, such as the creation of a pedestrianised seafront with late-night opening of amenities and facilities, that are likely to diminish the role of the traditional sea, sun and sand component of the overall holiday experience. 相似文献
349.
As a part of the carrying capacity system of tourism destination, tourism psychological carrying capacity and its makeup are very important indexes which reflect the harmonious development of tourism destination develops harmoniously, but the academy has not paid enough attention to them. Based on the concept and connotation of psychological carrying capacity, this paper explains the influencing factors which affect the psychological capacity of the tourist and the resident after the acknowledged concept, and then designs a harmonious development model of tourism destination. Finally, it offers some countermeasures against the overloading psychological capacity. 相似文献
350.
Most examples that support the substitution‐habitat hypothesis (human‐made habitats act as substitutes of original habitat) deal with birds and mammals. We tested this hypothesis in 14 amphibians by using percentage occupancy as a proxy of habitat quality (i.e., higher occupancy percentages indicate higher quality). We classified water body types as original habitat (no or little human influence) depending on anatomical, behavioral, or physiological adaptations of each amphibian species. Ten species had relatively high probabilities (0.16–0.28) of occurrence in original habitat, moderate probability of occurrence in substitution habitats (0.11–0.14), and low probability of occurrence in refuge habitats (0.05–0.08). Thus, the substitution–habitat hypothesis only partially applies to amphibians because the low occupancy of refuges could be due to the negligible human persecution of this group (indicating good conservation status). However, low occupancy of refuges could also be due to low tolerance of refuge conditions, which could have led to selective extinction or colonization problems due to poor dispersal capabilities. That original habitats had the highest probabilities of occupancy suggests amphibians have a good conservation status in the region. They also appeared highly adaptable to anthropogenic substitution habitats. 相似文献