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61.
Panorpa vulgaris   has become a model insect for testing theories of sexual selection. This contribution summarizes that which has been learned in recent years and presents new data that clearly show that the mating system of P. vulgaris is not simply a resource-defense polygyny, as has previously been thought. In P. vulgaris neither the pattern in food exploitation nor the ratio of variance in the lifetime reproductive success of the two sexes is in accordance with that expected in resource defense polygynous mating systems. Lifetime mating duration is the most important proximate determinant of male fitness. Males employing alternative mating tactics obtain copulations of varying duration in relation to the following sequence: saliva secretion  1  food offering  1  no gift. The number of salivary masses which males provide to females during their lifetime is significantly correlated with the lifetime condition index. The condition index depends on the fighting prowess of males and their ability to find food items. Thus saliva secretion of Panorpa is considered a Zahavian handicap, which can serve as an honest quality indicator used by mating females. Our results confirm four main predictions of the indicator model of the theory of sexual selection: (a) the indicator signals high ecological quality of its bearer, (b) the indicator value increases with phenotypic quality, (c) the indicator value is positively correlated with the genetic quality affecting offspring fitness in a natural selection context, and (d) the quality indicator is more costly for low- than for high-quality individuals. The evolutionary consequences of the mating pattern and the sperm competition mechanism in P. vulgaris are discussed in the context the way in which sexual selection creates and maintains sperm mixing and the evolution of a promiscuous mating system.  相似文献   
62.
Book reviews     
Making Cities Work: the role of local government in the urban environment. Richard Gilbert, Don Stevenson, Herbert Girardet & Richard Stren, 1996, London, Earthscan, 203pp. ISBN 1 85383 354 1, £13.95 pbk

Environmental Policy in an International Context, Vols 1-3: Perspectives, Conflicts and Prospects. P. Glasbergen & A. Blowers (Series Eds) London, Arnold

Rhetoric and Reality in Environmental Policy. M. Wintle & R. Reeve (Eds), 1994, Aldershot, Avebury Studies in Green Research, 154 pp. ISBN 1 85628 927 3

FutureNatural: Nature, Science, Culture. G. Roberston et al. (Eds) 1996, London, Routledge, ISBN 0415 070139, £40.00 hbk

Environmental Policy with Political Integration: the European Union and the United States. New horizons in environmental economics. John B. Braden, Henk Folmer & Thomas S. Ulen (Eds), 1996, Cheltenham, Elgar Publishing, 477 pp. ISBN 1 85898 217 0  相似文献   
63.
64.
This paper focuses on the role of marine parks and reserves in the conservation of Hong Kong's coastal environment. This environment is under serious threat as a result of pollution of marine waters and habitat loss associated with urbanisation, large-scale reclamation projects, and inadequate treatment and disposal of sewage and industrial effluents. The paper discusses whether in a highly urbanised and stressed environment like Hong Kong, which currently lacks a conservation strategy and an overall framework for handling sustainability issues, small marine parks and reserves can be effective in helping to conserve local biodiversity. The paper also suggests that Hong Kong should adopt a broader regional perspective on its coastal conservation and management problems, a perspective that recognises the significance for the territory of the rapid urban and industrial development taking place in neighbouring Guangdong Province. This will require more extensive and focused liaison with Chinese agencies.  相似文献   
65.
Agricultural economics has, until the 1990s, enjoyeda reputation for relevance and usefulness to theagri-food industry and policy-makers. Thatreputation has been jeopardized by a growinginfatuation with models and quantification, and aconcomitant underemphasis placed on many complexproblems and issues of society. An illustrativeexample is explored, using agriculturalactivity-related damage to the natural resourcebase, environment and ecology. Agriculturaleconomists are urged to respond by broadening theirterms of reference and joining forces with otherdisciplines.  相似文献   
66.
Over the last few years, commentators on all sides of the environmental debate have (with a few exceptions) joined hands to pillory the traditional model of environmental regulation in this country. The catch phrase “command and control” has become emblematic of everything that was seen as being wrong with the old system. The current push for “reinvention” of environmental regulation reinforces the concept that although traditional methods have produced progress, they have outlived their usefulness. At the same time, ISO 14000 has emerged as one of the hottest topics in the environmental field—a form of reinvention of environmental management that has been embraced by many as the solution to an array of problems. While it is still early in the game, initial results indicate that when used effectively, ISO 14000 can be a powerful tool for the environmental manager. However, misuse of ISO 14000 could represent a throwback to command and control rather than a management tool for the new millennium. This article examines how this new tool fits into the evolving picture of environmental regulation and management.  相似文献   
67.
ABSTRACT: Watershed functions that dominate the hydrologic environment are identified and discussed. Hydrological and ecological functions are considered in relation to the storm and annual hydrographs, and to water quality. Two integrative watershed responses to these functions are also articulated. Since most of the Earth's water is in storage, consideration of the hydrologic cycle as movement between water storage sites enhances this functional and response characterization of the watershed which, in turn, suggests guidance and direction for the restoration of watershed functions.  相似文献   
68.
The project on Biodiversity Uncertainties and Research Needs (BURN) ensures the advancement of usable knowledge on biodiversity by obtaining input from decision makers on their priority information needs about biodiversity and then using this input to engage leading scientists in designing policy-relevant research. Decision makers articulated concerns related to four issues: significance of biodiversity; status and trends of biodiversity; management for biodiversity; and the linkage of social, cultural, economic, legal, and biological objectives. Leading natural and social scientists then identified the research required to address the decision makers' needs and determined the probability of success. The diverse group of experts reached consensus on several fundamental issues, helping to clarify the role of biodiversity in land and resource management. The BURN participants identified several features that should be incorporated into policy-relevant research plans and management strategies for biodiversity. Research and assessment efforts should be: multidisciplinary and integrative, participatory with stakeholder involvement, hierarchical (multiple scales), and problem- and region-specific. The activities should be focused regionally within a global perspective. Meta-analysis of existing data is needed on all fronts to assess the state of the science. More specifically, the scientists recommended six priority research areas that should be pursued to address the information needs articulated by decision makers: (1) characterization of biodiversity, (2) environmental valuation, (3) management for sustainability—for humans and the environment (adaptive management), (4) information management strategies, (5) governance and stewardship issues, and (6) communication and outreach. Broad recommendations were developed for each research area to provide direction for research planning and resource management strategies. The results will directly benefit those groups that require biodiversity research to address their needs—whether to develop policy, manage natural resources, or make other decisions affecting biodiversity.  相似文献   
69.
There are numerous technologies currently being tested by EPA, universities throughout the world, and private research organizations. A few of the more promising innovative technologies as well as fully tested and proven remedies for treating contaminated groundwater are presented in this article. Although several of those technologies have been in existence for only four to five years, the results of full-scale testing are being produced. The method for each of these promising technologies is described, results from recent field-scale studies are summarized, and a discussion of cost is presented.  相似文献   
70.
The following report is a case study example of how problematic information can invade and percolate through the literature on forensic human factors and ergonomics. Initially, a highly doubtful assertion was used to bolster an argument made in a legal case of wrongful death. The assertion was supported through reference to a number of cited works. When the trail of evidence was pursued, however, it became clear that diverse citations had all branched from one, single, original and doubtful source. The fundamental issue, whether children have one third less peripheral vision than adults turns out to be much more complex than the original, simplistic spatial conception suggested. The case study illustrates the importance of ascertaining original citations and is yet another example of the frustration that often accompanies forensic activity where financial and legal concerns frequently over-ride the fundamental search for knowledge.  相似文献   
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