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131.
A number of hypotheses have been proposed to explain the evolution of multiple mating in the honeybee queen. In particular,
the consequences of reduced intracolonial relatedness provide plausible explanations for multiple mating with up to ten drones,
but fail to account for the much higher mating frequencies observed in nature. In this paper, we propose an alternative mechanism
which builds on non-linear relationships between intracolonial frequencies in genotypic worker specialization and colony fitness.
If genes for any worker specialization confer an advantage on colony fitness only when they are rare, this would require a
stable mix of sperm from a few drones which contribute that trait, and many which do not. To ensure both specific, low within-colony
proportions of “rare specialist” genes, and to reduce random variation of these proportions would require mating with high
numbers of drones. The quantitative implementation shows that moderate to very high numbers of matings are required to exploit
colony advantages from genotypic allocation of workers to rare tasks. Extreme polyandry thus could result from colony selection
dependent on the intracolonial frequency of rare genetic specialists.
Received: 30 January 1998 / Accepted after revision: 7 October 1998 相似文献
132.
Oddmund Kleven A. Moksnes Eivin Røskaft Marcel Honza 《Behavioral ecology and sociobiology》1999,47(1-2):41-46
The cuckoo (Cuculus canorus) is an obligate interspecific brood parasite. When about to lay an egg, the female must decide which nest to parasitise.
A high-quality host species should be preferred, to enhance the possibility of producing a viable offspring. In this study,
we investigated the effects of two closely related host species, the great reed warbler (Acrocephalus arundinaceus) and the reed warbler (A. scirpaceus) on the growth rate of cuckoo nestlings. We found that cuckoo nestlings raised by the larger host species, the great reed
warbler, grew significantly faster and became statistically significantly larger at fledging than nestlings raised by the
smaller host, the reed warbler. Our results indicate a qualitative difference between the two host species. The great reed
warbler, considered to be the best host, was parasitised at a higher rate than the reed warbler.
Received: 2 February 1999 / Received in revised form: 3 September 1999 / Accepted: 18 September 1999 相似文献
133.
The Mexican government has an innovative policy model for biodiversity conservation and rural development that includes permissible use of wildlife within a System of Land Management Units (SUMA, by its Spanish acronym). This co-management approach has been successful in terms of landowner participation, since the SUMA currently covers 38.2 million hectares (nearly 20% of Mexican territory). However, after 18 years of implementation, there has been no comprehensive evaluation by which to assess its effectiveness at national level. This article introduces the SUMA policy, its implementation and outcomes, and proposes a framework for conducting institutional monitoring and evaluation within an adaptive co-management approach. Our methodology comprised analysis of the achievements and challenges reported through interviews with stakeholders, journals and grey literature, and a review of the SUMA Information System (SIS) and its decision-making information needs. As result we have developed a set of 40 environmental, social and economic indicators grouped into five distinct but complementary dimensions within a sustainability framework: (I) Biodiversity conservation,(II) Wildlife management, (III) Economics, (IV) Social welfare and (V) Administration. These indicators can be incorporated into the SIS in order to support program evaluation and strengthen decision-making. Our article provides specific pathways for developing policy-oriented evaluation systems for worldwide biodiversity and conservation initiatives. 相似文献
134.
论地震灾害心理研究的内容与目标 总被引:5,自引:0,他引:5
依据1976年唐山大地震后的现场调查材料,考察了地震灾害给人造成的心理伤害,分析了震灾心理的形成机制和表现特征,提出了地震灾害心理研究的基本内容和目标,同时对地震灾害发生后实施心理救助的问题也做了一些探讨。 相似文献
135.
Colette S. Vogeler Johanna Hornung Nils C. Bandelow 《Journal of Environmental Policy & Planning》2020,22(4):518-530
ABSTRACT Sustainable agriculture implies trade-offs with farm animal welfare. Proposals to increase agricultural productivity and ecological sustainability alike, are often linked to intensification, which may restrict animal welfare. Despite the growing importance of farm animal welfare for the alignment of agricultural and environmental policy, determinants of decision-making at the EU level remain unexplored. This article contributes to closing this research gap, broadening our understanding of why policymakers vote for the enactment of animal welfare policies. Applying the Social Identities in the Policy Process (SIPP) perspective we highlight the role of group membership for individual decision-making. By means of a quantitative analysis of voting behaviour in the European Parliament on two animal welfare policies, we show that different identities are salient. The strongest predictor is political group membership. In case of defections from the group line, the salience of national, sectoral and also demographic identities adds to the understanding of decision-making. 相似文献
136.
137.
Community water supply programmes are seen as instrumental in achieving the goal of ‘safe’ water for all. Women, a principal target group of these programmes, are to be benefited with greater convenience, enhanced socio‐cultural opportunities and better health for themselves and their families, provided through improved water facilities. Water supply programmes largely consist of three essential components, namely: technology, people and institutions. Although such programmes are intended to benefit women members of local communities, scant attention is paid to the impacts of the socio‐cultural context of the community on these programmes. This article explores the influence of social and cultural intricacies on the implementation of community water supply programmes, and assesses their effectiveness. The article offers important lessons for the design and implementation of this type of programme. It concludes that the local socio‐cultural context sets the stage for programme implementation, being a dynamic factor that determines actual access to water sources, more so than mere physical availability, which is often used as a criterion for programme performance. The article stresses the urgent need to integrate socio‐cultural factors as a fourth dimension in designing community water supply programmes, and suggests practical measures for enhancing the effectiveness of such programmes. 相似文献
138.
Land-use planning using geographic information systems (GIS) commonly emphasizes biophysical spatial data; however planning
can be improved by integrating spatial sets of socioeconomic data into the GIS. As an example, we compared a traditional GIS-aided
forestry planning protocol that considered only biophysical suitability, with an integrated GIS-aided approach that incorporated
both biophysical and socioeconomic suitability. The analyses were conducted for the planning of plantation investments in
the Kyaukpadaung Township in the dry zone of central Myanmar. The traditional approach used three biophysical layers for suitability:
land use, slope, and accessibility. In contrast, the integrated GIS approach included biophysical suitability data, perceptions
and preferences of local villagers towards forestry (social suitability), and quantitative socioeconomic data. The results
indicated that the integrated approach provided two principal benefits over the traditional method. First, the integrated
method resulted in a more precise idea of suitable sites for plantation investment that could benefit more rural people and
also lead to greater investment efficiency. Second, incorporating social preference into the GIS takes into account the crucial
element of social capital (viz., social preference), which should lead to higher levels of community acceptance of plantation
projects because those plantations would be established on socially suitable land. A second GIS exercise showed how conservation
investment decisions could be informed using the integrated method. The results of this study support the idea that GIS-aided
planning activities can be enhanced through the incorporation of social data into the analysis. When applicable, spatial data
collection efforts for GIS-based planning exercises should incorporate spatial socioeconomic data. 相似文献
139.
Jeff Fox 《Environmental management》1984,8(3):243-249
People's dependence on firewood as a primary source of energy is causing serious deforestation problems in many developing countries. Reliable information on firewood consumption rates is needed to develop afforestation plans and to control deforestation. This study compares three methods used to determine firewood consumption in a Nepali village. Cultural and environmental factors that affect firewood consumption in the village are also examined.Theweight survey proved to be the most accurate method used. The less precisedaily recall andannual recall surveys overestimated actual firewood consumption by factors of 1.76 and 1.95, respectively. Overestimates are attributed to both physical and social factors. In view of the good agreement between daily and annual recall surveys, and the much greater ease of conducting the latter, annual recall surveys are recommended as the most practical method of monitoring firewood consumption rates. Validating the survey with occasional weighed measurements is suggested as a means of improving accuracy. 相似文献
140.