The behaviour of ant transporters at the old and new nests during successive colony emigrations

Colonies of the ant Temnothorax albipennis improve their collective performance over successive emigrations (Langridge et al. Behav Ecol Sociobiol 56:523–529, 2004, Behav Ecol Sociobiol 62:447–456, 2008). Here, by analysing the performance of individual transporters (workers that carry the brood, queen and a proportion of adults), we investigate whether they spend less time at the old and new nests during repeated emigrations. Transporters expedited choosing and picking up brood items at the old nest and depositing them in the new nest. Such improvements were not associated with adult transport. Generally, when carrying brood items, but not when carrying adults, transporters visited several locations in the new nest before depositing them. Transporters did not interact with other adults when depositing brood items. Consequently, reductions in depositing times are the sum of time savings made by individual transporters. By contrast, transporters spent most time interacting with other adults before picking up brood items at the old nest. As the frequency of these interactions did not decline, we suggest the behaviours of interacting adults were modified in a way that hastened their completion. Thus, reductions in picking-up times probably occur because of time saved during interactions.     

环境保护纪念日活动的经验

总结了策划和组织环境保护纪念日活动的一些做法和取得的效果,以"六.五"世界环境日为例,进行了主要经验教训的总结。     

黄河下游流域严重缺水成因分析

阐述了黄河水利枢纽库容及黄河中上游拦水筑坝现状。采用库容径流比,分析了黄河流域拦水筑坝的影响及黄河下游流域严重缺水的原因。总结了黄河流域水利枢纽建设中的经验与教训。提出了改进建议。     

Learning abatement costs: On the dynamics of the optimal regulation of experience goods

We study the introduction of new technologies when their costs are subject to idiosyncratic uncertainty and can only be fully learned through individual experience. We set up a dynamic model of clean experience goods that replace old polluting consumption options and show how optimal regulation evolves over time. In our base setting where social and private learning incentives coincide, the optimal tax on the polluting consumption is increasing over time. We show, however, that if social and private learning incentives diverge because the private discount rate exceeds the social discount rate, it may be optimal to temporarily increase the tax rate beyond net marginal external damages to induce more learning before reducing the tax rate to the steady state level. Alternatively, one could complement the tax with subsidies for first-time users which can be phased out over time. Similar results apply if consumers have biased expectations. We therefore give a rationale for introductory subsidies on new, clean technologies and non-monotonic tax paths from a perspective of consumer learning.     

What do pairing patterns in common tern, Sterna hirundo, recruits reveal about the significance of sex and breeding experience?

In general, reproductive output in long-lived bird species increases in older compared to younger individuals. Therefore, experienced mates should be advantageous for first-time breeders. To examine requirements and consequences of experienced pair mates we investigated the first pair bonds of common terns, Sterna hirundo, recruiting to their natal colony. We found that male recruits were usually the same age as their mates, whereas female recruits were usually the younger member of the pair. In order to acquire experienced mates, it was necessary for males to arrive early in the year of recruitment. Mates with 2 or more years of breeding experience were only attainable by male recruits characterised by greater body mass and age. Female recruits arrived more than 1 week later than their experienced mates and significantly later in the season than male recruits paired with experienced females. In general, females first bred at a younger age than males, and neither the female recruits body mass nor their age was related to the level of experience of their first mate. These sex-specific differences in obtaining an experienced mate did not result in different levels of reproductive success between the sexes. Male and female recruits with mates with 2 or more years breeding experience benefited from having experienced mates: they had greater reproductive success. First-time breeders paired with mates with only 1 year of breeding experience did not differ from pairs where both members were breeding for the first time in terms of reproductive success, but clutches were larger. Our results illustrate not only different prerequisites for males and females, but also males need for experienced mates. Delayed male breeding (postponing breeding for another year), supposed to be a negative trait, and high body mass, supposed to be a trait of superior individual quality, can be combined in some individuals, improving reproductive success and showing that breeding common terns use a range of tactics to begin reproduction.Communicated by F. Trillmich     

Improvement in collective performance with experience in ants

We show that entire ant colonies can improve their collective performance progressively when they repeat the same process. Colonies of Leptothorax albipennis can reduce their total emigration times over successive emigrations. We show that this improvement is based on experience and some memory-like process, rather than a coincidental developmental change or an increased general level of arousal. We demonstrate that the benefits of experience can be lost (i.e. forgotten) if the interval between successive emigrations is too long. We also show that the benefits of experience are more likely to be retained over a longer period if the collective performance has been repeated several times. This is a new demonstration of a process akin to learning in ants and we briefly discuss how it may involve not only improvements in individual performance but also improvements in the ways in which the ants interact with one another.Communicated by L. Sundström     

Paternity analysis shows experience,not age,enhances mating success in an aquatically mating pinniped,the Weddell seal (<Emphasis Type="Italic">Leptonychotes weddellii</Emphasis>)

For polygynous mammals with no paternal care, the number of offspring sired is often the sole measure of male reproductive success. The potential for polygyny is highest when resources or other environmental factors such as restricted breeding sites force females to aggregate. In these circumstances, males compete intensely for females and mating success may vary greatly among males, further intensifying selection for those traits that confer an advantage in reproduction. Hence, determinants of male success in competition for females are likely to be under strong sexual selection. Paternity analysis was used in conjunction with measures of age, site fidelity, and behavior during the breeding season to assess variance in male breeding success in Weddell seals (Leptonychotes weddellii) breeding at Turtle Rock, McMurdo Sound (77.727S, 166.85E) between 1997 and 2000. Paternity could be assigned to 177 pups at relaxed or 80% confidence level or 111 pups at strict or 95% confidence levels. Weddell seals at Turtle Rock show a modest degree of polygyny with the greatest number of pups sired by any individual male in a single season equalling 5 or ∼10% of the pups born. Over four consecutive years, most (89.2%) males sired at least one pup. In a generalized linear model (GLM), age and the age first seen at the study site as an adult were unrelated to mating success, but adult experience, either site-specific or elsewhere in McMurdo Sound, over the reproductive life span of males explained nearly 40% of variance in total mating success with 80% confidence and 24% of variance at 95% confidence. While learning where females are likely to be may enhance male reproductive success, aquatic mating reduces the ability of males to monopolize females, and thereby increases equity in mating success.     

大气固定污染源的控制体制和支持系统

国家作出了污染物总量控制的决策，它要求必须建立完善的污染物控制体系。文章结合了发达国家环境管理的成功经验，以框架方式论述了大气固定污染源的控制体制和支持系统。对固定源的管理体制论述包括环境标准、最佳控制技术、最大限度削减排放的原则、排污许可证制度、宽限期、公众参与、监测、处罚等项；支持系统论述包括管理人员、法规与标准、技术支持等项。     

Sustainable development strategies: Tools for policy coherence

Many different approaches for national sustainable development strategies (NSDS) have been proposed since 1992, with some components common to all. A country's national strategy should be designed to help mainstream environmental concerns into policy. More broadly, it should coordinate local policy with global concerns, as well as integrate scientific knowledge into policy and development planning. The peer review mechanism for national strategies was piloted by France, and also involved representatives of countries from the North and the South as well as stakeholders. The peer review process allows countries to share their experience and information, and can assist them in identifying their own path to sustainable development. The business community can also contribute to sustainable development through provision of local and global public goods. Another input to sustainable development could come from the International Organization for Standardization (ISO) and its Guidance Standard on Social Responsibility (ISO 26000), as a coordinating mechanism between voluntary initiatives and binding obligations (such as international conventions). ISO standards and guidelines should therefore be integrated with national sustainable development strategies and local Agenda 21 frameworks.     

我国地方层面生态补偿实践经验与借鉴

生态补偿机制的构建,不仅有利于缩小区际间的差距,还原生态以价值,而且还是环境降压的出口,促进环境建设,走可持续发展的道路。文章以生态补偿实践应用的角度为切入点,从流域、省域和地市3个层面系统分析了地方生态补偿的实践经验,在此基础上提出了现有的实践经验对我国地方层面生态补偿所带来的借鉴与启示。