Acoustic communication in phaneropterid bushcrickets: species-specific delay of female stridulatory response and matching male sensory time window

Summary The stridulatory sounds and movements produced by the females of various bushcricket species (Tettigonoidea: Phaneropteridae: Barbitistini) are compared with those of the males. Behavioral experiments are carried out to determine the significance of the female sounds in acoustic communication. Selection factors involved in the evolution of female stridulation are discussed. The morphological apparatus for sound production has evolved independently in males and females. Whereas males rub a toothed file on the underside of the left wing over the inner edge of the right wing, the plectrum, the females stridulate by rubbing a thickened vein on the underside of the left wing over modified spines on the upper surface of the right wing (Fig. 2). Similarly, the movements responsible for sound production are not homologous in males and females. In the male the audible closing movement is always preceded by wing opening, whereas the female in general initiates the closing movement when the wings are in the resting slightly opened position, and abruptly produces complete closure (Fig. 3, 4 and 5). The female responds to male singing by emitting one to several highly damped sound pulses each lasting less than one ms. The interval between the song of a conspecific male and this response is a very precise species-specific characteristic (Fig. 7). In species with male songs that are complicated in structure or continuous, the females respond only at specific time-after patticular markers in the song of the male. The time interval between male song and female response is an important criterion by which the male identifies conspecific female song (Fig. 8). Because the response delay of the female and corresponding neuronal time window in the male are distinct they may be important in species discrimination.     

Do heavy metals and metalloids influence the detoxification of organic xenobiotics in plants?

Background, aim and scope  

Mixed pollution with trace elements and organic industrial compounds is characteristic for many spill areas and dumping sites. The danger for the environment and human health from such sites is large, and sustainable remediation strategies are urgently needed. Phytoremediation seems to be a cheap and environmentally sound option for the removal of unwanted compounds, and the hyperaccumulation of trace elements and toxic metals is seemingly independent from the metabolism of organic xenobiotics. However, stress reactions, ROS formation and depletion of antioxidants will also cause alterations in xenobiotic detoxification. Here, we investigate the capability of plants to detoxify chlorophenols via glutathione conjugation in a mixed pollution situation.     

Estimating PM2.5 over southern Sweden using space-borne optical measurements

In the present study Bremen aerosol retrieval (BAER) columnar aerosol optical thickness (AOT) data, according to moderate resolution imaging spectroradiometer (MODIS) and medium resolution imaging sensor (MERIS) level 1 calibrated satellite data, have been compared with AOT data obtained with the MODIS and MERIS retrieval algorithms (NASA and ESA, respectively) and by AErosol RObotic NETwork (AERONET). Relatively good agreement is found between these different instruments and algorithms. The R² and relative RMSD were 0.86 and 31% for MODIS when comparing with AERONET and 0.92 and 21% for MERIS. The aerosols investigated were influenced by low relative humidity. During this period, a relatively large range of aerosol loadings were detected; from continental background aerosol to particles emitted from agricultural fires. In this study, empirical relationships between BAER columnar AOT and ground-measured PM_2.5 have been estimated. Linear relationships, with R² values of 0.58 and 0.59, were obtained according to MERIS and MODIS data, respectively. The slopes of the regression of AOT versus PM_2.5 are lower than previous studies, but this could easily be explained by considering the effect of hygroscopic growth. The present AOT–PM_2.5 relationship has been applied on MERIS full resolution data over the urban area of Stockholm and the results have been compared with particle mass concentrations from dispersion model calculations. It seems that the satellite data with the 300 m resolution can resolve the expected increased concentrations due to emissions along the main highways close to the city. Significant uncertainties in the spatial distribution of PM_2.5 across land/ocean boundaries were particularly evident when analyzing the high resolution satellite data.     

Preferential flow of bromide, bentazon, and imidacloprid in a Dutch clay soil

Leaching to ground water and tile drains are important parts of the environmental assessment of pesticides. The aims of the present study were to (i) assess the significance of preferential flow for pesticide leaching under realistic worst-case conditions for Dutch agriculture (soil profile with thick clay layer and high rainfall) and (ii) collect a high-quality data set that is suitable for testing pesticide leaching models. The movement of water, bromide, and the pesticides bentazon [3-isopropyl-1H-2, 1,3-benzothiadiazine-4(3H)-one-2,2-dioxide] and imidacloprid [1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine] was monitored in a clay soil for about 1 yr. The 1.2-ha field was located in the central part of the Netherlands (51 degrees 53' N, 5 degrees 43' E). The soil was a Eutric Fluvisol cropped with winter wheat (Triticum aestivum L.). Tile drains were present at a 0.8- to 0.9-m depth and the ground water level fluctuated between a 0.5- and 2-m depth. All chemicals were applied in spring. None of the soil concentration profiles showed bimodal concentration distributions. However, for each substance the highest concentration in drain water was found in the first drainage event after its application, which indicates preferential flow. This preferential flow is probably caused by permanent macropores that were present in the 0.3- to 1.0-m layer. At the time of the first drainage event, the drain water concentration of each substance was about an order of magnitude higher than its ground water concentration. Thus, the flux concentrations in drain water proved to be a more sensitive detector of preferential flow than the resident concentrations in the soil profile and the ground water.     

Spatial assessment of the economic feasibility of short rotation coppice on radioactively contaminated land in Belarus, Ukraine, and Russia. I. Model description and scenario analysis

The economic feasibility of short rotation coppice (SRC) production and energy conversion in areas contaminated by Chernobyl-derived (137)Cs was evaluated taking the spatial variability of environmental conditions into account. Two sequential GIS-embedded submodels were developed for a spatial assessment, which allow for spatial variation in soil contamination, soil type, and land use. These models were applied for four SRC production and four energy conversion scenarios for the entire contaminated area of Ukraine, Belarus, and Russia and for a part of the Bragin district, Belarus. It was concluded that in general medium-scale SRC production using local machines is most profitable. The areas near Chernobyl are not suitable for SRC production since the contamination levels in SRC wood exceed the intervention limit. Large scale SRC production is not profitable in areas where dry and sandy soils predominate. If the soil contamination does not exceed the intervention limit and sufficient SRC wood is available, all energy conversion scenarios are profitable.