Do "White" and "Green" Look the Same to a Bee?

 The hexagon model of color vision predicts that white flowers which reflect ultraviolet light resemble green foliage to a bee's eye, whereas, according to other models of the bee color vision, UV-reflecting white is discriminable from foliage green. The hexagon model is widely used in ecologically and evolutionary oriented literature, and the predicted similarity between white and green has been recently presented as a well established fact (Waser and Chittka 1998). We show that bees detect UV-reflecting white objects presented on a green background, a finding that is in disagreement with the predictions of the hexagon model. Received: 22 March 1999 / Accepted in revised form: 2 July 1999     

Use of coupling agents to stabilize asphalt–rubber–gravel composite to improve its mechanical properties

The mechanical performance of rubber-modified asphalt roads depends, besides the intrinsic properties of the constituents (asphalt, rubber and gravel), on their interfaces. To improve the adhesion between constituents, two different coupling agents were required: one to link asphalt with the rubber particles to stabilize the composite creating an elastic network in the interior of the material to improve its elastic recovery, and other to increase the adhesion between the hydrophobic asphalt and the hydrophilic gravel. A phenolic resin was used to link the rubber particles with the asphalt, while a switterionic molecule (phosphatidyl-choline) was used to change the OH groups on the gravel surface by hydrocarbon chains to make it compatible with the asphalt.     

横加公司诉美国政府案对我国应对环境邻避冲突的法律启示

美国对邻避冲突现象的关注和研究较早,2015年刚被时任总统奥巴马否决的加拿大横加公司(Trans Canada Corp)"拱心石XL管道"(Keystone XL Pipeline)项目,是一起引发大规模邻避冲突的典型案例。本文介绍了"拱心石XL管道"项目的概况,分析了项目激起邻避冲突的原因,以及俄克拉荷马州政府和联邦政府在对待"拱心石XL管道"项目上的迥异态度。据此得出对我国应对环境邻避冲突的法律启示:跨区域公共项目在央地层面应保持一致、从项目选址的地方立法寻求突破、加大环境影响评价报告等信息公开力度、强化示范项目建设及规范企业行为。     

Sustainable resource management coupled to resilient germplasm to provide new intensive cereal–grain–legume–livestock systems in the dry savanna

Sustainable resource management is the critical agricultural research and development challenge in sub-Saharan Africa. The accumulated knowledge on soil management gathered over the last 10 years, combined with solid crop improvement and plant health research at farmers’ level, has brought us to a stage where we can now address with confidence the intensification of cereal–grain–legume-based cropping systems in the dry savanna of West Africa in a sustainable and environmentally positive manner.Two sustainable farming systems that greatly enhance the productivity and sustainability of integrated livestock systems have been developed and implemented in the dry savanna of Nigeria. These are: (i) maize (Zea mays L.)–promiscuous soybean [Glycine max (L.) Merr.] rotations that combine high nitrogen fixation and the ability to kill large numbers of Striga hermonthica seeds in the soil; and (ii) miflet [Eleusine coracana (L.) Gaerth] and dual-purpose cowpea [Vigna unguiculata (L.) Walp.]. Improvement of the cropping systems in the dry savanna has been driven by the adoption of promiscuously nodulating soybean varieties (in particular TGx 1448-2E) and dual-purpose cowpea. The rate of adoption is very high, even in the absence of an efficient seed distribution system. The number of farmers cultivating the improved varieties increased by 228% during the last 3 years. Increased production of promiscuous soybean has been stimulated by increased demand from industries and home utilization. Production in Nigeria was estimated at 405,000 t in 1999 compared to less than 60,000 t in 1984. Economic analysis of these systems shows already an increase of 50–70% in the gross incomes of adopting farmers compared to those still following the current practices, mainly continuous maize cultivation. Furthermore, increases in legume areas of 10% in Nigeria (about 30,000 ha in the northern Guinea savanna) and increases of 20% in yield have translated into additional fixed nitrogen valued annually at US$ 44 million. This reflects, at the same time, an equivalent increase in land-use productivity, and with further spread of the improved crops, there are excellent prospects for additional economic and environmental benefits from a very large recommendation domain across West Africa.     

Floral CO<Subscript>2</Subscript> emission may indicate food abundance to nectar-feeding moths

As part of a study of the roles of the sensory subsystem devoted to CO₂ in the nectar-feeding moth Manduca sexta, we investigated CO₂ release and nectar secretion by flowers of Datura wrightii, a preferred hostplant of Manduca. Datura flowers open at dusk and wilt by the following noon. During the first hours after dusk, when Manduca feeds, the flowers produce considerable amounts of nectar and emit levels of CO₂ that should be detectable by moths nearby. By midnight, however, both nectar secretion and CO₂ release decrease significantly. Because nectar production requires high metabolic activity, high floral CO₂ emission may indicate food abundance to the moths. We suggest that hovering moths could use the florally emitted CO₂ to help them assess the nectar content before attempting to feed in order to improve their foraging efficiency.Electronic Supplementary Material  Supplementary material is available in the online version of this article at     

Political commitment to CO<Subscript>2</Subscript> capture and storage: evidence from government RD&;D budgets

For CO₂ capture and storage (CCS) to succeed as a mitigation strategy, political commitment is one of several prerequisites. This article offers an appraisal of political commitment to a CCS strategy among high-income countries in Europe and North America: Which governments are committed, and what particular interests and concerns do they seek to accommodate by supporting CCS? In order to answer these questions, new data are reported on government CCS research, development and demonstration (RD&;D) budgets. RD&;D budgets divided by GDP is used as an indicator of political commitment, and explanations are sought for cross-national differences. The analysis shows that fossil fuels reserves and extraction within a country has a very strong bearing on funding levels. Likely explanations include the potential for combining CCS with enhanced resource recovery. All large economies (population >50 million) have a funding program. The smaller states that provide funding (Norway, Canada, the Netherlands) have the highest funding levels relative to GDP. These findings suggest that high-income petroleum producing countries are likely to be leaders in promoting CCS and a favorable regulatory environment. The fact that all large, high-income countries in the two regions now display some interest in CCS further improves its political outlook.     

Evasive response to ultrasound by the crepuscular butterfly<Emphasis Type="Italic"> Manataria maculata</Emphasis>

The crepuscular nymphalid butterfly Manataria maculata was studied in Monteverde cloud forest, Costa Rica, during the dry season reproductive diapause. M. maculata has ears in the form of Vogel's organs located near the base of the forewings. Its behaviour in response to bursts of ultrasonic pulses (26 kHz, 110 dB SPL at 1 m) was condition-dependent. At dusk and dawn the sound consistently elicited evasive responses, similar to those of moths, in flying individuals. In contrast day-roosting individuals always remained motionless although they were alert to other stimuli. The daily movements between day- and night-roosts coincided in time and light intensity with the activity of insectivorous bats. This is the first reported case of ultrasonic hearing connected to evasive flights in a true butterfly (Papilionoidea). It strongly supports the idea that echolocating bats were involved in the evolution of hearing in butterflies.     

丹麦绿色发展经验对我国生态文明建设的借鉴意义

<正>随着中国经济30多年的高速增长,能源和环境的压力日趋严重。中国的可持续发展之路应该如何走?是否可以借鉴其他国家和地区现成的经验少走弯路?通过研究和比较世界各国的节能减排和生态文明建设实践经验,我们发现,如果把中国,美国和欧盟三大能源消耗体做一比较,欧盟国家显然走在了世界前列,而丹麦表现尤其突出。以"零碳"为目标的"丹麦绿色发展"模式,已经成为全球探寻能源供应和安全最成功的"实验室",充分证明了人类只要选对了正确     

Uncertainty in Agricultural CH<Subscript>4</Subscript> AND N<Subscript>2</Subscript>O Emissions from Finland – Possibilities to Increase Accuracy in Emission Estimates

According to the United Nations Framework Convention on Climate Change (UNFCCC) and Kyoto Protocol under it, industrial countries have to estimate their greenhouse gas emissions annually, and assess the uncertainties in these estimates. In Finland, agricultural methane (CH₄) and nitrous oxide (N_2O) emissions represent 7% of anthropogenic greenhouse gas emissions, and globally the share is much higher. Agriculture is one of the most uncertain emission categories (representing over 20% of greenhouse gas inventory uncertainty in Finland), due to both high natural variability of the emission sources and poor knowledge of the emission-generating processes. In this paper, we present an uncertainty estimate of agricultural CH₄ and N₂O emissions from Finland in 2002. Uncertainties were estimated based on measurement data, literature and expert judgement, and total uncertainty in agriculture was calculated using Monte Carlo simulation. According to the calculations, agricultural CH₄ and N₂O emissions from Finland were 3.7 to 7.8 Tg carbon dioxide (CO₂) equivalents, 5.4 Tg being the mean value.Estimates of CH₄ emissions are more reliable than those of N₂O. N₂O from agricultural soils was the most uncertain emission category, and the uncertainty was not reduced by using available national measurement data of N₂O fluxes. Sensitivity study revealed that the uncertainty in total agricultural inventory could be 7% points lower, if more accurate emission estimation methods were used, including 1) improved data collection in area estimates of organic soils, 2) climate-specific methods for N₂O from agricultural soils as already presented in literature, and 3) more detailed CH₄ estimation methods for enteric fermentation which can be achieved by investigating national circumstances and digestible systems of animals in more detail.     

Soil moisture determines the effectiveness of two urease inhibitors to decrease N<Subscript>2</Subscript>O emission

Among the mitigation strategies to prevent nitrogen (N) losses from ureic fertilizers, urease inhibitors (UIs) have been demonstrated to promote high N use efficiency by reducing ammonia (NH₃) volatilization. In the last few years, some field experiments have also shown its effectiveness in reducing nitrous oxide (N₂O) losses from fertilized soils under conditions of low soil moisture. An incubation experiment was carried out with the aim of assessing the main biotic mechanisms behind N₂O emissions once that the UIs N-(n-butyl) thiophosphoric triamid (NBPT) and phenil phosphorodiamidate (PPDA) were applied with Urea (U) under different soil moisture conditions (40, 60 and 80 % water-filled pore space, WFPS). In the same study we tried to analyze to what extent soil WFPS regulates the effect of these inhibitors on N₂O emissions. The use of PPDA in our study allowed us to compare the effect of NBPT with that of another commercially available urease inhibitor, aiming to see if the results were inhibitor-specific or not. Based on the results from this experiment, a WFPS (i.e. 60 %) was chosen for a second study (i.e. mesocosm experiment) aiming to assess the efficiency of the UIs to indirectly affect N₂O emissions through influencing the pool of soil mineral N. The N₂O emissions at 40 % WFPS were almost negligible, being significantly lower from all fertilized treatments than that produced at 60 and 80 % WFPS. When compared to U alone, NBPT+U reduced the N₂O emissions at 60 % WFPS but had no effect at 80 % WFPS. The application of PPDA significantly increased the emissions with respect to U at 80 % WFPS whereas no significant effect was found at 60 %. At 80 % WFPS, denitrification was the main source of N₂O emissions for all treatments. In the mesocosm study, the application of NBPT+U was an effective strategy to reduce N₂O emissions (75 % reduction compared to U alone), due to a lower soil ammonium (NH₄ ⁺) content induced by the inhibitor. These results suggest that adequate management of the UI NBPT could provide, under certain soil conditions, an opportunity for mitigation of N₂O emissions from fertilized soils.     

三江平原保护区社区居民对湿地生态系统服务功能的贡献意愿

为了解社区对维持保护区湿地生态系统服务功能的贡献意愿,研究选取三江平原5个湿地自然保护区及其社区,依据条件价值评估法设计双边界二分式问卷,进行实地走访调查,从居民社会经济背景等方面探讨影响贡献意愿的因素、居民支付意愿（WTP）和劳动意愿（WTW）的差异。结果表明：1）居民对湿地生态系统服务的劳动意愿（73.57%）高于支付意愿（55.65%）,居民的抗议支付率随WTP和WTW投标值增加呈上升趋势,人均WTP为387.25±7.08元/a,WTW为31.40±0.39 h/月;2）月收入水平较高及对支付金钱有较高接受程度的受访居民,其WTP相对较高;加入环保类协会、对付出劳动的接受程度较高、受教育程度较高及男性的受访居民,则有较高的WTW;3）49.46%的居民愿意同时贡献金钱与劳动,远高于其他贡献意愿类型。建议在保护区的资源保护与管理实践中鼓励社区参与,充分发挥社区居民乐于提供志愿服务时间的贡献意愿。     

Microbiota disruption leads to reduced cold tolerance in <Emphasis Type="Italic">Drosophila</Emphasis> flies

It is now acknowledged that bacteria from gut microbiota deeply interact with their host by altering many physiological traits. Such interplay is likely to consequently affect stress tolerance. Here, we compared cold and heat tolerance of Drosophila melanogaster flies with undisrupted (control (Co)) versus disrupted gut microbiota (dechorionated eggs (De)). The disrupting treatment strongly reduced bacterial load in flies’ guts, though 16S sequencing analysis did not evidence strong diversity changes in the remaining bacterial community. Both chill coma recovery and acute cold survival were repeatedly lower in De than in Co flies under our experimental conditions. However, heat tolerance was not consistently affected by gut disruption. Our results suggest that microbiota-related effects on the host can alter ecologically relevant traits such as thermal tolerance.     

Aqueous Extracts of <Emphasis Type="Italic">Hibiscus sabdariffa</Emphasis> Calyces to Control Aichi Virus

Aqueous Hibiscus sabdariffa extracts possess antimicrobial properties with limited information available on their antiviral effects. Aichi virus (AiV) is an emerging foodborne pathogen that causes gastroenteritis. Vaccines are currently unavailable to prevent their disease transmission. The objective of this study was to determine the antiviral effects of aqueous H. sabdariffa extracts against AiV. AiV at ~5 log PFU/ml was incubated with undiluted (200 mg/ml), 1:1 (100 mg/ml) or 1:5 (40 mg/ml) diluted aqueous hibiscus extract (pH 3.6), phosphate-buffered saline (pH 7.2 as control), or malic acid (pH 3.0, acid control) at 37 °C over 24 h. Treatments were stopped by serially diluting in cell-culture media containing fetal bovine serum and titers were determined using plaque assays on confluent Vero cells. Each treatment was replicated thrice and assayed in duplicate. AiV did not show any significant reduction with 1:1 (100 mg/ml) or 1:5 (40 mg/ml) diluted aqueous hibiscus extracts or malic acid after 0.5, 1, or 2 h at 37 °C. However, AiV titers were reduced to non-detectable levels after 24 h with all the three tested concentrations, while malic acid showed only 0.93 log PFU/ml reduction after 24 h. AiV was reduced by 0.5 and 0.9 log PFU/ml with undiluted extracts (200 mg/ml) after 2 and 6 h, respectively. AiV treated with 1:1 (100 mg/ml) and 1:5 (40 mg/ml) diluted extracts showed a minimal ~0.3 log PFU/ml reduction after 6 h. These extracts show promise to reduce AiV titers mainly through alteration of virus structure, though higher concentrations may have improved effects.     

Behavioural responses of the snail<Emphasis Type="Italic"> Lymnaea acuminata</Emphasis> to carbohydrates in snail-attractant pellets

Snail control is one of the most important tools in the campaign to reduce the incidence of fascioliasis. In order to attain this objective, the method of bait formulation in order to contain an attractant and a molluscicide is an expedient approach to lure the target snail population to the molluscicide. This study identifies certain carbohydrates, namely sucrose, maltose, glucose, fructose and starch, for preparing such baits. These were tested on Lymnaea acuminata, an intermediate host of the digenean trematodes Fasciola hepatica and Fasciola gigantica. The behavioural responses of snails to these carbohydrates were examined. Significant variations in behavioural responses were observed in the snail even when the five carbohydrates were used in low concentrations in snail-attractant pellets. Starch emerged as the strongest attractant for Lymnaea acuminata, followed by maltose.     

Avian phenotypic traits related to feeding preferences in two <Emphasis Type="Italic">Culex</Emphasis> mosquitoes

Host choice by mosquitoes affects the transmission dynamics of vector-borne infectious diseases. Although asymmetries in mosquito attraction to vertebrate species have been reported, the relative importance of host characteristics in mosquito blood-feeding behavior is still poorly studied. Here, we investigate the relationship between avian phenotypic traits—in particular, morphometry, plumage coloration, and nesting and roosting behavior—and the blood-feeding patterns in two common Culex mosquito species on a North American avian community. Forage ratios of the mosquito species were unrelated to the phylogenetic relationships among bird species. Culex pipiens fed preferably on birds with lighter-colored plumage and longer tarsi; furthermore, solitary roosting avian species were both bitten by Cx. pipiens and Cx. restuans more often than expected. These associations may be explained by greater mosquito attraction towards larger birds with a greater color contrast against the background. Although communally roosting birds may release more cues and attract more mosquitoes, individuals may in fact receive fewer bites due to the encounter-dilution effect. Mosquito feeding behavior is a highly complex phenomenon, and our results may improve understanding of the non-random interaction between birds and mosquitoes in natural communities.     

韩国应对大气颗粒物污染问题的政策导向与几点建议

中韩两国正共同面对日益凸显的大气颗粒物污染问题,出于对韩国推卸大气污染责任的防范和积极推动中韩环境合作的双重考虑,亟待加强对韩国大气污染防治问题的研究。本文分析了韩国媒体及公众对雾霾问题的认识和态度,探析了韩国政府应对雾霾所采取的一系列策略及其特点,并对促进我国跨界大气污染问题的妥善解决提出了政策建议。     

<Emphasis Type="Italic">Drosophila melanogaster</Emphasis> virgins are more likely to mate with strangers than familiar flies

Recent evidence shows that females of many species can discriminate against males and/or male phenotypes they have mated with previously. However, these studies have not tested whether actual mating is necessary to induce the avoidance behaviour. A preference for strangers may have evolved because it avoids multiple matings with similar genotypes. Alternatively, there may be selection against mating with familiar individuals directly. By choosing its first mate among unfamiliar individuals (which are less likely close relatives than are those encountered early in life), a virgin might disentangle some of the potential benefits of avoiding genetic incompatibility and inbreeding in the offspring from the costs of remating. In this study, we test whether Drosophila melanogaster flies bias their mate choice towards strangers according to previous, non-copulatory, experience. Based on 173 trials over 12 weeks, virgin females presented with two virgin males were 59% more likely to mate with a novel male than the one which she had been housed with for 8 h the day before. Hence we present the first report showing that a dipteran can distinguish between previously encountered and not previously encountered conspecifics.