Experience-dependent choices ensure species-specific fragrance accumulation in male orchid bees

Male neotropical orchid bees (Euglossini) collect volatile chemicals from orchid flowers and other sources and store them in hind leg cavities. The accumulated fragrance bouquets are later emitted at mating sites. Although most other insects synthesize pheromone blends de novo, specific euglossine perfumes are derived from active choices in a changing fragrance market. Male bees of three species of Euglossa possessed distinctive fragrance phenotypes showing little variation by locality and habitat in mainland Central America. In cage experiments, fragrance choice by male Euglossa imperialis was influenced markedly by a bee's collection history. Collection of a given chemical strongly reduced its attractiveness on subsequent occasions, an effect that was retained over days. Experimentally adding the chemicals directly to bee hind legs produced no effect. We conclude that bees learn and remember chemicals they collect. Innate odor preferences, memory and the avoidance of overcollecting by negative feedback may be the primary mechanisms that ensure unique blends of pheromone analogs in these tropical forest bees.Supplementary material is available in the online version of this article at and is accessible for authorized users.An erratum to this article can be found at     

Water management strategies against toxic Microcystis blooms in the Dutch delta.

To prevent flooding of the Dutch delta, former estuaries have been impounded by the building of dams and sluices. Some of these water bodies, however, experience major ecological problems. One of the problem areas is the former Volkerak estuary that was turned into a freshwater lake in 1987. From the early 1990s onward, toxic Microcystis blooms dominate the phytoplankton of the lake every summer. Two management strategies have been suggested to suppress these harmful algal blooms: flushing the lake with fresh water or reintroducing saline water into the lake. This study aims at an advance assessment of these strategies through the development of a mechanistic model of the population dynamics of Microcystis. To calibrate the model, we monitored the benthic and pelagic Microcystis populations in the lake during two years. Field samples of Microcystis were incubated in the laboratory to estimate growth and mortality rates as functions of light, temperature, and salinity. Recruitment and sedimentation rates were measured in the lake, using traps, to quantify benthic-pelagic coupling of the Microcystis populations. The model predicts that flushing with fresh water will suppress Microcystis blooms when the current flushing rate is sufficiently increased. Furthermore, the inlet of saline water will suppress Microcystis blooms for salinities exceeding 14 g/L. Both management options are technically feasible. Our study illustrates that quantitative ecological knowledge can be a helpful tool guiding large-scale water management.     

New tools and strategies for the inspection of the psychosocial working environment: The experience of the Danish Working Environment Authority

In 2007 the Danish Working Environment Authority launched a new strategy to strengthen and qualify primary prevention of work related stress. Part of the strategy consists of increased inspections of the psychosocial working environment as well as the development and implementation of a new inspection tool, namely the “guidance tool”.Twenty-four sector specific guidance tools have been developed to help WEA inspectors assess psychosocial working environment problems in all Danish enterprises. Based on recent research, the guidance tools consist, in each sector, of the three to five most important risk factors (for example quantitative demands, emotional demands, and work related violence), as well as the most important preventive factors, e.g. quality of management, influence/control and training.During the first years of the strategy, an increasing number of inspectors have issued improvement notices regarding work related stress and violence, and there has been an increasing number of notices issued on several risk factors. For some aspects, the tools have helped increase the clarity and comprehensibility of the improvement notices and reduce the WEA’s time consumption per enterprise.The guidance tools seem to be a suitable and efficient way of assessing several health and safety risks concerning work related stress and violence thereby allowing the WEA to detect more of the existing problems. Future challenges projected for the strategy include continuously training all WEA inspectors in the proper use of the tools and continuously refining the tools – or developing new tools – based on further research and experiences from practice.     

Drivers of illegal resource extraction: An analysis of Bardia National Park,Nepal

While park-people conflicts have received worldwide attention, the extent of illegal resource extraction and the relationship with communities’ livelihoods has gained little attention in the literature. Thus this paper investigates the impact of socio-economic factors involved in illegal fuel wood and fodder extraction at Bardia National Park in Nepal. Household questionnaires, key-informant interviews and focus groups were conducted to identify different plant species used by households and explore the causes and mode of resource extraction in three buffer zone villages in the park. Altogether 50 different plants were identified by villagers that were used regularly for different livelihood purposes. Almost half of the respondents met their needs by illegally and regularly extracting resources from the park. Incentive schemes in the form of development projects were important but not sufficient in meeting the basic needs of households’ especially for such daily items such as fuel wood and fodder. The results described in this paper showed that proximity and access to resources either in the national park, the buffer zone community forest or the government forest, and impact on the livelihoods significantly influenced the likelihood of illegal resource extraction activities. Villages that differed in terms of their location to the resource base, the provision of alternative resources and influence of these on their livelihoods showed significant differences in terms of their patterns of resource extraction and use of these resources. As resource use options, resource interest, and resource extraction patterns were different between villages and dependent on circumstances specific to villages, site-specific management strategies were necessary and more influential than the enforcement of ‘one-size fits all’ policies. It is suggested that park management plans should be flexible and adaptive enough to meet site-specific contexts and to endear wider support from local communities.     

Dynamic floodplain vegetation model development for the Kootenai River, USA

The Kootenai River floodplain in Idaho, USA, is nearly disconnected from its main channel due to levee construction and the operation of Libby Dam since 1972. The decreases in flood frequency and magnitude combined with the river modification have changed the physical processes and the dynamics of floodplain vegetation. This research describes the concept, methodologies and simulated results of the rule-based dynamic floodplain vegetation model "CASiMiR-vegetation" that is used to simulate the effect of hydrological alteration on vegetation dynamics. The vegetation dynamics are simulated based on existing theory but adapted to observed field data on the Kootenai River. The model simulates the changing vegetation patterns on an annual basis from an initial condition based on spatially distributed physical parameters such as shear stress, flood duration and height-over-base flow level. The model was calibrated and the robustness of the model was analyzed. The hydrodynamic (HD) models were used to simulate relevant physical processes representing historic, pre-dam, and post-dam conditions from different representative hydrographs. The general concept of the vegetation model is that a vegetation community will be recycled if the magnitude of a relevant physical parameter is greater than the threshold value for specific vegetation; otherwise, succession will take place toward maturation stage. The overall accuracy and agreement Kappa between simulated and field observed maps were low considering individual vegetation types in both calibration and validation areas. Overall accuracy (42% and 58%) and agreement between maps (0.18 and 0.27) increased notably when individual vegetation types were merged into vegetation phases in both calibration and validation areas, respectively. The area balance approach was used to analyze the proportion of area occupied by different vegetation phases in the simulated and observed map. The result showed the impact of the river modification and hydrological alteration on the floodplain vegetation. The spatially distributed vegetation model developed in this study is a step forward in modeling riparian vegetation succession and can be used for operational loss assessment, and river and floodplain restoration projects.     

ECOSM-a new joint project for assessing environmental risks of poorly soluble compounds used in cosmetics-project presentation

This article reports on the second Young Environmental Scientists Meeting that was hosted from 28 February to 2 March 2011 by the Institute for Environmental Research at RWTH Aachen University, Germany. This extraordinary meeting was again initiated and organized by the Student Advisory Council under the umbrella of Society of Environmental Toxicology and Chemistry Europe. A movie about the meeting and the abstracts of poster and platform presentations are freely available as supplemental material of this article.