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91.
Clint D. Kelly 《Behavioral ecology and sociobiology》2008,62(6):855-871
A long-standing hypothesis in behavioural ecology posits that males with greater resource-holding potential (RHP) control
resource sites deemed more valuable by sexually-receptive females and, thereby, males controlling such sites accrue greater
reproductive success (RS). This hypothesis has historically been investigated using three separate but non-mutually exclusive
relationships (male RHP vs. resource value, resource value vs. male RS and male RHP vs. RS). The relationships between these
three variables are predicted to be strongly positive, however, due to measurement error and biological noise, perfect correlations
(r = 1.0) are rare in biology even for well-established relationships. Moreover, the inaccurate identification of either the
male trait(s) important to RHP or the resource characteristic sought by females will weaken the observed strength of the relationships.
Here, I use meta-analysis to quantitatively describe the general pattern of these relationships in animals. I predict that
the relationships between male RHP, resource-value and RS should be significantly positive (male RHP and resource-value should
explain a large amount of the variation in male RS). My meta-analysis supports this hypothesis; however, in the best case
scenario only ca. 20% of the variation in the response variable was explained. I conclude by identifying areas in which we
need to improve our investigations of resource-defence animals and recommending approaches to meet these needs.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
92.
G. W. Uetz William J. McClintock Douglas Miller Elizabeth I. Smith Kristina K. Cook 《Behavioral ecology and sociobiology》1996,38(4):253-257
Males of the brush-legged wolf spider Schizocosa ocreata (Hentz) have conspicuously decorated forelegs used in courtship and agonistic displays. Approximately one in five juvenile
males has a missing or regenerating foreleg, and regeneration of a leg lost during development usually results in the absence
of a decorative tuft on that leg. The subsequent asymmetry in this male secondary character significantly decreases success
in both courtship of females and male-male agonistic interactions. Experimental removal of tufts from one leg of previously
successful symmetric males produces similar results. As a test for concomitant behavioral effects, female spiders were shown
video images of a courting male with symmetric tufts and the same video image altered to have asymmetric tufts. Female receptivity
to the asymmetric video image was lower. In contrast to fluctuating asymmetry resulting from developmental instability, leg
tuft asymmetry in S. ocreata most likely arises from a single event during ontogeny – possibly leg loss from an aggressive or predator encounter – and
may serve as a quality indicator in female mate choice.
Received: 27 July 1995/ Accepted after revision: 19 November 1995 相似文献
93.
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
94.
Abstract: Mate choice by females can introduce difficulties to captive breeding programs because there may be a conflict between the conservation manager's choice of mate (based on random allocation or maximizing heterogeneity) and the females' own preferences, often resulting in incompatibility and aggression. Similar effects are caused by inappropriate social contexts at the time of pairing. We manipulated the social experience of male and female harvest mice ( Micromys minutus ) to investigate whether we could enhance compatibility between randomly allocated mates by altering female preferences. In one experiment, we used a choice test to identify female preferences between two males and then varied the competitive context of unpreferred males by transferring competitor's scent marks into their cages. The manipulation caused them to increase their investment in a form of olfactory signaling (scent marking), which female rodents use as an indicator of male quality when choosing mates. The manipulation increased their attractiveness relative to the initially preferred male when the choice test was repeated. In a second experiment, we tested the effect of females' familiarity with the odor of males by transfer of male scent marks to female cages. Females preferred familiar males in choice tests and were less aggressive toward them when pairs were introduced than females paired with unfamiliar males. This kind of approach can influence mate choice, and transferring scent marks between cages or collections is an effective and practical behavioral means of improving success in conservation breeding programs. 相似文献
95.
Guido Pennings 《黑龙江环境通报》2002,22(12):1123-1129
The arguments against the use of preimplantation genetic diagnosis (PGD) for non-medical sex selection are analysed. It is concluded that the distinction between medical and non-medical reasons is difficult to maintain, that the disproportionality of means and end is not a decisive counterargument and that the fear of damage to the reputation of PGD does not justify the refusal of controversial applications. Moreover, since non-medical sex selection does not belong to basic health care, it should not be equally accessible to all. The position defended in this article is founded on two basic principles: (1) medical reasons have priority on non-medical reasons, and (2) personal reasons do not qualify for public funding. In order to respect both principles, it is proposed that restrictions should be installed to control the number of requests for social sexing and that a tax should be imposed on these elective services. The tax should compensate the society for the investment it made in the training and education of the physician. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
96.
Abstract: Wide variation in reproductive success is common among amphibians that breed in seasonal ponds, but persistence of adults can buffer against these fluctuations, particularly for long-lived species. We hypothesized that the frequent episodes of catastrophic failure of the marbled salamander ( Ambystoma opacum ) enhance the importance of high terrestrial survival. At Rainbow Bay in South Carolina reproductive success was poor (<1 metamorph/breeding female) in nearly half of the 22 years that the species bred. Complete failure occurred in 6 of 22 years. To study catastrophic failure, we adapted an age-structured, individual-based model with density-dependent growth and survival of larvae. The model was based on extensive data from local field studies and experiments. With consistently good survival in the pond stages, the simulated population required survival probabilities in the upland stages (juveniles and adults) near 0.5/year to persist and near 0.8/year to achieve the increases observed. Catastrophic failure, occurring randomly with probability 0.5/year, created additional fluctuations in the population, raised the thresholds of survival required for persistence, and caused extinction under conditions that were otherwise favorable. The marbled salamander at Rainbow Bay is not at great risk of extinction because of catastrophic failure, but the risk increases dramatically if life span is decreased or frequency of failure is increased. Any reduction in terrestrial survival will have deleterious consequences by reducing the breeding populations at equilibrium, even if it does not jeopardize persistence. Our model provides assessments of risk that can be applied to poorly studied species with similar life histories, such as the endangered flatwoods salamander ( A. cingulatum ). 相似文献
97.
98.
研究松花江蓄洪区选址问题的决策方法.松花江蓄滞洪区选址问题涉及诸多定性指标和定量指标,属于半结构决策问题.本文综合层次分析法和模糊优选法,提出求解这类问题的一种半结构决策方法.基本方法是:将评价指标分为定性指标和定量指标;对于定性应用层次分析法,求其评价矩阵;对于定量指标应用相对隶属度方法,求其评价矩阵;二者合成得到全体指标的评价矩阵;最后利用模糊优选法求得最优决策.应用该方法于松花江流域蓄滞洪区的方案选择中. 相似文献
99.
100.
Industrial processes are often operated at conditions deviating from atmospheric conditions. Safety relevant parameters normally used for hazard evaluation and classification of combustible dusts are only valid within a very narrow range of pressure, temperature and gas composition. The development of dust explosions and flame propagation under reduced pressure conditions is poorly investigated. Standard laboratory equipment like the 20 l Siwek chamber does not allow investigations at very low pressures. Therefore an experimental device was developed for the investigations on flame propagation and ignition under reduced pressure conditions. Flame propagation was analysed by a video analysis system the actual flame speed was measured by optical sensors. Experiments were carried out with lycopodium at dust concentrations of 100 g/m3, 200 g/m3 and 300 g/m3. It was found that both flame shapes and flame speeds were quite different from those obtained at atmospheric pressure. Effects like buoyancy of hot gases during ignition and flame propagation are less strong than at atmospheric conditions. For the investigated dust concentrations the flame reaches speeds that are nearly an order of a magnitude higher than at ambient conditions. 相似文献