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1.
Mathias Kölliker 《Behavioral ecology and sociobiology》2007,61(9):1489-1497
The evolution of parental care and family group formation critically depends on offspring survival benefits and parental fecundity
costs of care under given ecological conditions. Investigations of the functional significance of care in insect species that
exhibit facultative parental care have been relatively rare but may be of particular interest for better understanding of
benefit and cost schedules at an early evolutionary stage. In this study, aspects of benefits and costs of care were addressed
in the sub-social European earwig (Forficula auricularia; Dermaptera: Forficulidae) by manipulating the presence of tending mothers and brood size in a fully crossed experimental
design. Larvae growing in broods tended by their mother or of reduced size showed a higher survival probability than larvae
growing in untended or large broods, as predicted if maternal care is beneficial and shaped by a trade-off between number
and quality of offspring. Analysis of patterns of food consumption and developmental time further suggested that the benefit
of maternal attendance is mediated by the maternal provisioning of food, while the quality–quantity trade-off seemed to be
driven by sibling rivalry. Further, tending mothers delayed the production of a second clutch, indicating a potential cost
of care in terms of lifetime fecundity. This study experimentally shows benefits and potential costs of maternal care and
family group formation in the European earwig. More detailed behavioural experiments will be required to fully understand
how behavioural interactions among family members mediate these reproductive outcomes. 相似文献
2.
Marta C. Soares Sónia C. Cardoso Isabelle M. Côté 《Behavioral ecology and sociobiology》2007,61(7):1015-1022
Predation risk is amongst the most pervasive selective pressures influencing behaviour and animals have been repeatedly shown
to trade-off foraging success for safety. We examined the nature of this trade-off in cleaning symbioses amongst Caribbean
coral reef fishes. We predicted that cleaning gobies (Elacatinus evelynae and Elacatinus prochilos) should prefer fish clients that pose a low risk of predation (e.g. herbivores) over clients that may have more ectoparasites
but pose a higher risk (e.g. piscivores). Our field observations revealed that cleaners did clean preferentially client species
with more parasites but predatory and non-predatory clients had similar ectoparasite loads. Despite the lack of a foraging
advantage for inspecting predators, cleaners did not avoid risky clients. On the contrary, a larger proportion of visiting
predators than non-predators was inspected, gobies initiated more interactions with predatory clients, and predators were
attended to immediately upon arrival at cleaning stations. This preferential treatment of dangerous clients may allow the
rapid identification of cleaners as non-prey item or may be due to the effect of predators on the rest of the cleaners’ clientele,
which avoided cleaning stations whilst predators were present. Dealing with potentially risky clients may allow gobies to
regain access to their main food source: non-predatory clients. 相似文献
3.
高彩霞 《中国环境管理干部学院学报》2005,15(4):120-123
悲剧意识是人类精神意识的重要组成部分.它源于人类的悲剧性存在,而又在其艺术的传达中充满了丰富性和灵动性.作为20世纪30年代一个风格特异的作家,萧红的悲剧人生、悲剧意识和其呈现出的审美特征,为我们观照社会、解析人生提供了一个别样的视角. 相似文献
4.
Female choice and male–male aggression are two modes of sexual selection that can lead to elaboration of male morphological
and behavioral traits. In lek-mating species, male mating success is often strongly skewed, and it is puzzling why variation
in male traits is still observed given directional female choice. If male traits correlated with reproductive success are
honest signals of male quality, there may be survival costs associated with the expression of those traits. In this study,
we examined whether morphological, behavioral, and territorial traits are correlated with male mating success and survival
in the lek-mating greater prairie-chicken (Tympanuchus cupido). We introduce a novel application of multinomial discrete choice models for analysis of female mate choice behavior. We
found that behavioral and territorial attributes showed 6.5 times more variability among males than morphological traits.
Both display and aggressive behaviors were strong predictors of male mating success, suggesting that both female choice and
male–male aggression were important in determining mating success among male greater prairie-chickens. Moreover, annual survival
of male prairie-chickens was independent of mating success and male traits. Females appear to be choosing males based on behavioral
traits where large variation exists between males (coefficient of variation >30%). Behavioral traits were the most important
factor in determining mating success of male prairie-chickens, but the mechanism underlying this relationship is unknown.
In the future, experimental manipulations of male hormones or parasite loads could bridge the proximate mechanisms and ultimate
consequences of factors mediating male mating success in lek-mating grouse. 相似文献
5.
土壤水分和氮素水平对春小麦水分与氮素利用效率的影响 总被引:1,自引:0,他引:1
以抗旱性不同的三个春小麦品种为材料,研究它们在不同水氮水平下水分利用效率(WUE)和氮素利用效率(NUE)的变化,探讨二者间的相关性。结果表明:三个品种中,和尚头和定西35号的WUE相当,而定西35号的NUE最高。三个春小麦品种叶片NUE均随施氮量增加而降低,整株水平的NUE与氮素水平负相关。施氮量对春小麦叶片光合作用的瞬时WUE影响不显著,整株WUE与施氮量显著正相关。水氮耦合作用对春小麦NUE具有重要影响,整株NUE对水分条件的响应表现出明显的氮水平依赖性。春小麦品种氮素利用和水分利用两个生理过程之间存在"负偶联"关系。 相似文献
6.
Stephen Syampungani Paxie W. Chirwa Festus K. Akinnifesi Gudeta Sileshi Oluyede C. Ajayi 《Natural resources forum》2009,33(2):150-159
The Miombo, the most extensive tropical woodland formation of Africa directly supports the livelihoods of over 100 million people through the provision of many tree products and ecosystem services essential to both the rural and urban communities. While the destruction of the Miombo has often been blamed on the rural communities dwelling near the forest resources, many urban dwellers depend heavily on the various products derived from the woodlands. This paper highlights the importance of the Miombo in the livelihoods of rural people, the potential threats to this ecosystem and opportunities for its sustainable management. About 70% of energy consumed in southern Africa is in the form of fuelwood or charcoal. The economic importance of the Miombo especially from non-timber forest products (NTFPs) is usually understated due to their perceived non-economic value yet they play an important role in sustaining livelihoods of forest dependent people in the miombo ecoregion. The Miombo also contributes to health services through the use of medicinal plant and products, in some cases, contributing up to 80% to rural health, including helping in coping with effects of HIV/AIDS, malaria and several diseases. The possibility of developing payment for environmental services schemes through public–private partnerships, and community-based sustainable management models are proposed. Through conservation and commercialization of some of the products and services, there is a potential to provide income and improve the livelihood of people involved in the trade along the value chain. 相似文献
7.
Changes in disturbance rates due to climate change may increase or decrease diversity, whereas permanent loss of habitat is generally believed to decrease diversity. It is, however, very likely that the effects of disturbances and habitat destruction interact. Understanding such combined effects is essential to predict the response of communities to global changes and in particular which functional types of species are most endangered. Using an individual-based spatially explicit community model, we investigate (1) whether diversity-disturbance curves alter when spatially uncorrelated or autocorrelated habitat destruction is added, and (2) which functional types of species are able to survive under these altered conditions. Model communities consisted of four functional types of species trading off between colonisation ability and competition strength. We found that habitat destruction may alter both height and shape of diversity-disturbance curves: maximum diversity at intermediate disturbance rates may shift to other disturbance rates or even split into two peaks giving rise to bimodal diversity-disturbance relationships with different sub-communities persisting at low and high disturbance rates. Diversity responded differentially depending on how the colonisation-competition trade-off was represented. Our results suggest that, for trade-offs in seed production rate, generally the best coloniser will better withstand the interacting effects of habitat destruction and changing disturbance rates; however, for trade-offs in mean dispersal distances, functional types characterized by intermediate abilities will perform best. We conclude that predictions of the impacts of changing disturbance rates on biodiversity depend on community structure and cannot be made without knowledge of concurrent permanent habitat destruction. 相似文献
8.
In recent years, there has been a growing concern and an increasing number of proactive initiatives from various stakeholders on issues related to the environment, social matters, and economic aspects and this has been the main driving force toward sustainability. However, most players that are deeply involved with environmental and social agendas indicate that these actions have been more of a temporary palliative for the current unsustainability problems than real structural solutions, especially in what concerns the relationship between short-term actions and long-term structural planning. Even though the general literature on sustainability is comprehensive, there is a paucity of papers which look at it at the organizational level, and under a cross-sectoral perspective. This paper is an attempt to address this gap. It presents the concept of ‘Hybrid Bottom Line’ as a new perspective in understanding and sustainability at the organizational level. 相似文献
9.
生态系统服务冲突及权衡的研究进展 总被引:1,自引:0,他引:1
生态系统提供了人类生活所需的各种产品,支撑和维护人们赖以生存的生态环境。由于人类对自然生态系统认识不足和使用不当,各种生态系统服务之间出现了冲突矛盾,限制着彼此的发挥,因此,权衡不同生态系统服务之间的关系具有重要意义。文章首先分析了冲突权衡(trade-off)产生的原因、类型差异和研究意义,接下来总结了冲突权衡分析方法进展、应用情况、有待解决的问题和未来重点研究方向。尽管对于生态系统服务的认识,尤其是价值评估已经得到了充分研究,但是生态系统服务的冲突与权衡还处于起步阶段,文章总结了当前生态系统服务权衡的热点问题,包括主要的权衡分析方法以及应用领域,提出展望和建议。未来的研究重点在以下2个方面:第一,深入研究各服务相互关联的作用因子和作用机制;第二,如何综合运用已知条件和方法,构建一个科学合理的权衡模式。 相似文献
10.
Qiuwen Chen Duan Chen Ruiguang Han Ruonan Li Jinfeng M Koen Blanckaert 《环境科学学报(英文版)》2012,24(11):1923-1928
For reservoir operation, maintaining a quasi-natural flow regime can benefit river ecosystems, but may sacrifice human interests. This study took the Qingshitan Reservoir in the Lijiang River as a case, and developed an optimization model to explore a trade-off solution between social-economic interests and nature flow maintenance on a monthly base. The objective function considered irrigation, cruise navigation and water supply aspects. An index of flow alteration degree was proposed to measure the difference between the regulated discharge and the natural flow. The index was then used as an additional constraint in the model besides the conventional constraints on reservoir safety. During model solving, different criteria were applied to the index, representing various degrees of alteration of the natural flow regime in the river. Through the model, a relationship between social-economic interests and flow alteration degree was established. Finally, a trade-off solution of the reservoir operation was defined that led to a favorable social-economic benefit at an acceptable alteration of the natural flow. 相似文献