We analyzed several species of the weevil family Mecininae (Coleoptera, Curculionidae) that all feed on iridoid glycoside
(IG) containing plants of the Plantaginaceae to investigate whether the beetles sequester these deterrent substances from
their host plants. Within the Mecininae two genera of the tribe Cionini were found to sequester aucubin and catalpol: Cionus Clairville
and Schellenberg and Cleopus Dejean. Both analyzed genera of the Mecinini, Mecinus Germar and Rhinusa Stephens, do not sequester IGs although the compounds are present in their food plants. They thus represent the first case of specialists
on IG plants that have not evolved adaptations to use the compounds. However, in contrast to the Cionini these genera have
a hidden lifestyle, so that their need for defence might be lower. Both Cionus and Cleopus, sequester catalpol with a higher efficiency than aucubin. However, in contrast to Cionus species, Cleopus species only sequester catalpol. In species feeding on Scrophularia, the aucubin concentration is higher while in beetles on Verbascum catalpol is usually dominating. This pattern can also be detected in the only species living on both plants, Cionus hortulanus. The ability to sequester IGs must have a single origin at the base of the sister genera Cionus and Cleopus. 相似文献
Ecological and physiological studies focused on dietary preferences, lipid biochemistry and energetics within the three Antarctic
chaetognaths Eukrohnia hamata, E. bathypelagica and E. bathyantarctica from meso- and bathypelagic depths. Eukrohnia hamata and E. bathypelagica respired 0.15 μL O2 mg dry mass (DM)−1 h−1, which translates to an average metabolic loss of only <1.1% of body carbon per day. Lipid storage was not substantial in
E. bathypelagica (mean 11.5 ± 6.5% DM) and E. bathyantarctica (mean 15.4 ± 4.1% DM) during summer and winter, suggesting year-round feeding of these predators mainly on copepods. In E. bathypelagica, total fatty acids were dominated by the fatty acids 16:0, 20:5(n-3) and 22:6(n-3) and in E. bathyantarctica also by 18:1(n-9), a fatty acid usually found in storage lipids. Only the latter species was characterized by significant
amounts of wax esters, consisting largely of the common fatty alcohols 16:0, 20:1(n-9) and the unusual fatty alcohol isomer
22:1(n-9). 相似文献
The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for
interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable
depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored
whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants (cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on
the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both
cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves
offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones. 相似文献
South Korea’s Civilian Control Zone (CCZ), a relatively untouched area due to tight military oversight since the end of Korean
War, has received considerable attention nationally and internationally for its rich biodiversity. However, the exclusion
of local communities from the process of defining problems and goals and of setting priorities for biodiversity conservation
has halted a series of biodiversity conservation efforts. Through qualitative research, we explored CCZ farmers’ views of
key problems and issues and also the sources of their opposition to the government-initiated conservation approaches. Key
findings include the farmers’ concerns about the impact of conservation restrictions on their access to necessary resources
needed to farm, wildlife impacts on the value of rice and other agricultural goods they produce, and farmers’ strong distrust
of government, the military, and planners, based on their experiences with past conservation processes. The findings regarding
farmers’ perceptions should prove useful for the design of future participatory planning processes for biodiversity conservation
in the CCZ. This case highlights how conservative measures, perceived to be imposed from above—however scientifically valuable—can
be undermined and suggests the value that must be placed on communication among planners and stakeholders. 相似文献
When integrating a post-combustion CO2 capture process and CO2 compression into a steam power plant, the three interface quantities heat, electricity and cooling duty must be satisfied by the power plant, leading to a loss in net efficiency. The heat duty shows to be the largest contributor to the overall net efficiency penalty of the power plant. Additional energy penalty results from the cooling and electric power duty of the capture and compression units.In this work, the dependency of the energy penalty on the quantity and quality of the heat duty is analyzed and quantified for a state-of-the-art hard coal fired power plant. Furthermore, the energy penalty attributed to the additional cooling and power duty is quantified. As a result correlations are provided which enable to predict the impact of the heat, cooling and electricity duty of post-combustion CO2 capture processes on the net output of a steam power plant in a holistic approach. 相似文献
Environmental Science and Pollution Research - Although the development and application of nanomaterials is a growing industry, little data is available on the ecotoxicological effects on aquatic... 相似文献
ABSTRACT: Data from 85 sites across the United States were used to estimate concentrations and yields of selected nutrients in streams draining relatively undeveloped basins. Flow‐weighted concentrations during 1990–1995 were generally low with median basin concentrations of 0.020, 0.087, 0.26, 0.010, and 0.022 milligrams per liter (mg/L) for ammonia as N, nitrate as N, total nitrogen, orthophosphate as P, and total phosphorus, respectively. The flow‐weighted concentration of nitrate exceeded 0.6 mg/L in only three basins. Total nitrogen exceeded 1 mg/L in only four basins, and total phosphorus exceeded 0.1 mg/L in only four basins. The median annual basin yield of ammonia as N, nitrate as N, total nitrogen, orthophosphate as P, and total phosphorus was 8.1, 26, 86, 2.8, and 8.5 kilograms per square kilometer, respectively. Concentrations and yields of nitrate tended to be highest in northeastern and mid‐Atlantic coastal states and correlated well with areas of high atmospheric nitrogen deposition. Concentrations and yields of total nitrogen were highest in the southeastern part of the nation and in parts of the upper Midwest. In the northeast, nitrate was generally the predominant form of nitrogen, and in the southeast and parts of the upper Midwest, organic nitrogen was the dominant form. Concentrations of total phosphorus were generally highest in the Rocky Mountain and Central Plain states. 相似文献
A new analytical method using accelerated solvent extraction was developed for the determination of 10 particle-associated polar and semipolar pesticides. In addition, six deuterated analogues of the target compounds were evaluated as internal standards. The method yielded acceptable accuracy (73–103% recovery) and precision (<25% relative standard deviation) for eight compounds. Using size exclusion chromatography (SEC) as cleanup step resulted in higher recoveries compared to solid phase extraction (SPE) cleanup.
Deuterated standards with 10 or more deuterium atoms performed well as internal standards concerning similar recovery and correlation with the target analytes.
The method was employed to extract particle-associated pesticides from 16 streams located in an area with intense agriculture in France. Acetochlor, pirimicarb, tebuconazole, fenpropidin, -endosulfan and chlorfenvinphos were detected at concentrations up to 1 mg kg−1 dry weight. A comparison with aquatic toxicity data indicated potential risk to the benthic fauna exposed to these concentrations of pirimicarb, -endosulfan and chlorfenvinphos.
We suggest that the method presented here be used for the extraction and quantitation of particle-associated polar pesticides. 相似文献
Effluent from sewage treatment plants has been associated with a range of pollutant effects. Depending on the influent composition and treatment processes the effluent may contain a myriad of different chemicals which makes monitoring very complex. In this study we aimed to monitor relatively polar organic pollutant mixtures using a combination of passive sampling techniques and a set of biochemistry based assays covering acute bacterial toxicity (Microtox), phytotoxicity (Max-I-PAM assay) and genotoxicity (umuC assay). The study showed that all of the assays were able to detect effects in the samples and allowed a comparison of the two plants as well as a comparison between the two sampling periods. Distinct improvements in water quality were observed in one of the plants as result of an upgrade to a UV disinfection system, which improved from 24x sample enrichment required to induce a 50% response in the Microtox assay to 84x, from 30x sample enrichment to induce a 50% reduction in photosynthetic yield to 125x, and the genotoxicity observed in the first sampling period was eliminated. Thus we propose that biochemical assay techniques in combination with time integrated passive sampling can substantially contribute to the monitoring of polar organic toxicants in STP effluents. 相似文献