Impact of Galerucella birmanica (Coleoptera: Chrysomelidae) on growth and seed production of Trapa natans

Success in biological weed control programs depends upon the ability of host-specific herbivores to suppress populations of their host plant. While pre-release predictions of field host range (i.e., specificity) appear widely accurate, predictions about which agent or agent combination may suppress plant populations have lately been compared to predictions in a lottery. The history of weed biocontrol does not offer immediately obvious approaches to improve the lottery model, however, pre-release assessments of the impact of different herbivore densities on the invasive plant may provide an opportunity to improve predictions of success. In this paper, we report on the impact of the leaf beetle Galerucella birmanica on growth and reproduction of water chestnut, Trapa natans, in the native range in China. At low herbivore densities (10–50 larvae/rosette), plants compensated for leaf herbivory by increasing leaf production at the expense of reproductive effort. Inoculating >50 first instar larvae per rosette greatly suppressed biomass production and plants were unable to grow when three or more G. birmanica pairs were released per seven rosettes. In the native range, similar densities are found in the field, resulting in complete defoliation of T. natans. Our study indicates that G. birmanica feeding has significant negative impacts on T. natans. This chrysomelid species appears to be a promising biological control agent and we would predict that the species will be able to attain sufficiently high populations to control its host plant—if approved for release in North America.     

Modulation by ellagic acid of DCA-induced developmental toxicity in the zebrafish (Danio rerio)

The ability of ellagic acid (EA) to modulate dichloroacetic acid (DCA)-induced developmental toxicity and oxidative damage was examined in zebrafish embryos. Embryos were exposed to 20 mM EA administered concomitantly with 32 mM DCA at 4 hours postfertilization (hpf) and 20 h later. Embryos were observed through 144 hpf for developmental malformations, and production of superoxide anion (SA) and nitric oxide (NO) was determined in embryonic homogenates. DCA was shown to produce developmental abnormalities and significant levels of SA and NO in zebrafish embryos. EA exposure alleviated the developmental malformations observed in treated embryos and decreased the levels of SA and NO in those same embryos. Less than 10% of DCA + EA exposed embryos showed developmental malformations compared to 100% of embryos treated with DCA alone. Animals in this group that developed malformations were shown to have fewer defects than those treated with DCA only. Taken together, the results confirm the involvement of oxidative stress in the developmental toxicity of DCA in zebrafish embryos, and suggest possible protection against those effects with the use of antioxidants.     

A Strategic Interpretation of Beetle (Coleoptera) Assemblages, Biotopes, Habitats and Distribution, and the Conservation Implications

The identification of beetle, and other invertebrate, biotopes based on the recording of species assemblages has become a regular occurrence as a result of increased survey work, with the approach expanded into classifications of grid square pooled species lists at the national scale. A reassessment of beetle biotopes and distribution has been attempted by interpreting the classifications in terms of the major environmental factors of productivity and disturbance, identified as being important drivers in work on habitat templates and strategic triangles. For grassland ground beetle biotopes, productivity was generally related to soil quality whilst disturbance was associated with land management or cover. Productivity of exposed riverine sediment ground beetle biotopes was dependent on deposited organic matter and disturbance on the effects of water flow on site structure. With both ground beetle biotopes, the distribution of assemblages was also affected by substrate water, another abiotic driver. Productivity in aquatic beetle biotopes was a function of base-status, generally reflected by pH, whilst disturbance was mainly due to water flow and wave action. However, disturbance in ditches was also the result of site vegetation management whilst another factor affecting assemblage distribution was water permanence, with temporary water having specific assemblages. For large-scale British, grid-based, classifications productivity and disturbance were interpreted from satellite-derived land cover data. At the national scale, the other important factor influencing distribution was temperature. There is a requirement for better quantification of a number of the factors influencing biotope and assemblage definition. Species strategies employed to cope with the various environmental variables were reflected in traits in such factors as morphology and life-cycles. The effects of environmental perturbations including climate change, pollution and land use are discussed in relation to the environmental variables and to the various species strategies. Biotope classifications, using standardised and reproducible survey methods, allied to a better understanding of the underlying environmental pressures, could produce a unified approach for the conservation of beetle and other invertebrate species.     

The stability of micro-organisms preserved in LENTICULE discs, demonstrated by repeat sample distributions of the EQUAL Scheme for Indicator Organisms (water microbiology)

Aims:  To demonstrate the stability of microorganisms preserved in LENTICULE discs, employed by the EQUAL Scheme for Indicator Organisms.
Methods and Results:  Five sample batches containing several indicator organism parameters were each despatched in two separate distributions at intervals of up to 24 months apart. A comparison of participants' median counts and bar charts of their cumulated results was then made.
Conclusions:  The results demonstrated that LENTICULE discs provided a remarkably stable preparation format for the maintenance of viable organisms in reproducible numbers.
Significance and Impact of the Study:  Complex mixtures of organisms can be maintained in stable numbers for extended periods of time at a freezer temperature of −20°C and satisfactorily transported without the requirement for cold chain conditions.     

Integrated Constructed Wetlands (ICW) for livestock wastewater management

Social, economic and environmental coherence is sought in the management of livestock wastewater. Wetlands facilitate the biogeochemical processes that exploit livestock wastewater and provide opportunities to achieve such coherence and also to deliver on a range of ecosystem services. The Integrated Constructed Wetland (ICW) concept integrates three inextricably linked objectives: water quantity and quality management, landscape-fit to improve aesthetic site values and enhanced biodiversity. The synergies derived from this explicit integration allow one of the key challenges for livestock management to be addressed. An example utilizing twelve ICW systems from a catchment on the south coast of Ireland demonstrates that over an eight year period mean reduction of total and soluble phosphorus (molybdate reactive phosphorus) exceeded 95% and the mean removal of ammonium-N exceeded 98%. This paper reviews evidence regarding the capacity of ICWs to provide a coherent and sustainable alternative to conventional systems.     

L'épithélium absorbant des vésicules coxales des Machilides (Insecta Thysanura)

Résumé Les Machilides présentent une série de vésicules abdominales paires, sous forme de sacs exsertiles capables d'absorber l'eau d'un film liquide. Les coupes histologiques montrent qu'une partie de la paroi de ces vésicules est faite d'un épithélium particulier revêtu d'une intima cuticulaire plus épaisse que celle de l'épithelium banal. La microscopie électronique permet de préciser la structure des cellules absorbantes qui sont caractérisés essentiellement par des microvillosités apicales et de profondes invaginations de la membrane plasmique basale associées à des mitochondries allongées. Une comparison est faite avec d'autres types de cellules absorbantes connues chez les Arthropodes, notamment dans le rectum. Grâce à leurs vésicules abdominales, les Thysanoures possèdent des organes originaux jouant un rôle important dans l'équilibre hydrique de ces insectes.

---

The absorbing epithelium of abdominal vesicles in machilida (Insecta thysanura)Histology and ultrastructure

Summary The Machilida are endowed with several abdominal vesicles which are protrusible sacs capable of absorbing water from the substrate surface. Histology shows that a part of their outer wall consists of a particular epithelium covered by a cuticular intima, which is thicker than the intima of the common epithelium. The absorbing cells are electronmicroscopically characterized by apical microvilli and deep infoldings of the basal plasma membrane which are associated with mitochondria. A comparison is drawn with other types of absorbing cells already known, especially with those in the rectum of insects. Thanks to their abdominal vesicles, the Thysanura possess unique organs which play an important role in the control of their water balance.

Nous exprimons nos remerciements à Monsieur le Professeur Ch. Noirot, qui a bien voulu nous faire part de ses remarques lors de la préparation de ce travail.     

Winter biology of the blacknose dace,Rhinichthys atratulus,in a southern Ontario stream

Synopsis The winter habitat of stream-dwelling blacknose dace Rhinichthys atratulus is identified and described from underwater observations in a southern Ontario stream. In late November as water temperatures declined below 5.0°C, dace moved into crevices beneath rubble with a mean maximum diameter of 15.9 cm. Focal point water depth was significantly greater in winter and mid-depth water velocity was significantly faster than measured in the summer. Dace were not observed in open water again until late March when water temperatures increased to 4.0°C. Winter diet analyses which showed minimal feeding were consistent with the seasonal changes in condition factor and percentage body water suggesting a general depletion of body reserves over winter. This physiological change was more pronounced in juveniles.     

野生大鲵繁殖洞穴生态环境的初步研究

为了探明野生大鲵(Andrias davidianus)自然繁殖所需要的主要生态条件,给人工养殖条件下大鲵的自然繁殖提供生态学依据,对张家界国家级大鲵保护区境内野生大鲵的栖息繁殖洞穴进行生态学考察。对海拔、洞口的宽度与高度等10个生态因子进行定量观测和主成分分析,结果表明,影响大鲵选择繁殖洞穴的主要因子是海拔、洞口高度、洞底组成,以及洞穴中水的透明度、pH、流速、饵料丰度7个因子。对大鲵繁殖洞穴相连河段进行调查,发现多为山溪流。对繁殖洞穴中水的溶解氧、化学耗氧量、硫化物等5项主要指标进行检测,除硫化物外,其他指标多达到国家饮用水的水质标准,可见大鲵自然繁殖对洞穴与水质的要求较高。     

Gabčíkovo River Barrage System: The Ecological Disaster and Economic Calamity for the Inland Delta of the Middle Danube

The Gabíkovo Water Project (GWP), a major construction of damming and canalizing on the upper part of the middle Danube was completed and put into operation in October 1992. It destroyed most of the 230km2 of wetlands. Two-thirds of the wetlands are becoming dry, discontinuous or severely changed which will ultimately destroy the original ecosystem and lead to a decline in biological diversity. Based upon detailed knowledge of the limnology and fish biology of this section of the Danube River the effects of the GWP were predicted as early as 1964. All the recent post-construction impact studies of the GWP report few negative effects and so the planners and builders defend the project. It is difficult to believe that all sides in the current GWP legal controversy have overlooked the most important point. Any effects immediately after construction are purely transitory. A large body of published empirical and theoretical information clearly shows that the mostly negative effects of such large water projects become apparent only several years or decades after construction. The value of the destroyed wetland and river floodplain is at least US $ 520 million per year, and clearly incriminates the VV (Vodohospodárska výstavba) of fraudulent representation of 'benefits'. The enormous flood of devious publications glorifying the work of the VV in recent years should be interpreted as a cover up for the bad conscience of the builders. The International Court of Justice in the Hague delivered its judgement on the GWP case on 25 September 1997. There were no winners in this case as both Slovakia and Hungary were said to have acted inappropriately: it was illegal for Hungary to stop its part on the project according to the treaty of 1977, and Slovakia had no right to put Gabíkovo into operation unilaterally. As the Court dealt little with the social, environmental and economic aspects of the GWP, the true losers became the inland delta of the Danube, the last large wetland of Europe, and the local inhabitants.     

不同pH值对三角帆蚌珍珠质分泌的影响

运用多种组织化学方法和透射电镜技术,研究了５种ｐＨ水环境（ｐＨ５、６、７、８、９）对三角帆砷外套膜珍珠质分泌的影响机制,结果表明,在中性水环境中,贝体能积极地从外界水环境中吸收钙,并能旺盛地合成和分泌贝壳珍珠层及珍珠有机基质前体物质,持续的酸性水环境导致贝体的钙严重丢失,并引起珍珠质分泌细胞对有机基质前体物质的合成和分泌能力减弱,持续的碱性水环境虽能导致贝体对钙的积累,但珍珠质分泌细胞合成和分泌珍