Defence and development in a gregarious leaf-mining beetle

Abstract.

• 1 The gregarious larvae of the chrysomelid beetle Microrhopala vittata mine the leaves of goldenrods (Solidago spp.). These mines serve both as food and as shelter for the larvae.
• 2 Life-table data and experiments indicated that mine initiation and moves to secondary mines represented especially vulnerable stages during larval development. Leaf mines effectively protected M.vittata against predators in the field.
• 3 Field experiments indicated that larvae hatching from larger clutches of eggs stood a greater chance of surviving to pupation, primarily because larvae hatching in groups proved more successful at initiating leaf mines. Once inside the leaf mine, however, larvae feeding in large groups attained lower adult masses, and were more likely to abandon the natal mine and did so earlier in development because large groups more rapidly destroyed a leaf.

     

不同生态型摩西球囊霉菌株对蜈蚣草砷吸收的影响

砷超富集植物——蜈蚣草无论是在野外或是在室内均能被丛枝菌根真菌(AM真菌)侵染,但其对蜈蚣草砷吸收及转运的机理尚不清晰.本研究将分离于湖南省郴州市金川塘某铅锌尾矿蜈蚣草根际土壤(Glomus mosseae BGC GD01,简称污染菌株)和云南省未污染土壤(G.mosseae BGC YN05,简称非污染菌株)的2种摩西球囊霉菌株分别接种于非污染生态型和污染生态型蜈蚣草根际,8周后利用菌根化蜈蚣草幼苗在浓度为100 μmol·L-1砷(Na2HAsO4·7H2O)营养液中进行为期24 h的水培试验.结果表明,2种生态型摩西球囊霉菌株分别与蜈蚣草形成中等程度侵染,侵染率为25.2％ ～31.3％.无论是接种污染菌株或是非污染菌株,均明显促进了蜈蚣草根部对磷的吸收.在24 h水培试验期间,接种非污染菌株显著促进了蜈蚣草根部砷的吸收,但接种污染菌株对蜈蚣草根部砷吸收的促进作用有限,说明AM真菌对蜈蚣草砷吸收存在种内差异.     

A test of the matched filter hypothesis in two sympatric frogs,Chiromantis doriae and Feihyla vittata

The matched filter hypothesis proposes that the auditory sensitivity of receivers should match the spectral energy distribution of the senders’ signals. If so, receivers should be able to distinguish between species-specific and hetero-specific signals. We tested the matched filter hypothesis in two sympatric species, Chiromantis doriae and Feihyla vittata, whose calls exhibit similar frequency characters and that overlap in the breeding season and microenvironment. For both species, we recorded male calls and measured the auditory sensitivity of both sexes using the auditory brainstem response (ABR). We compared the auditory sensitivity with the spectral energy distribution of the calls of each species and found that (1) auditory sensitivity matched the signal spectrogram in C. doriae and F. vittata; (2) the concordance conformed better to the conspecific signal versus the hetero-specific signal. In addition, our results show that species differences are larger than sex differences for ABR audiograms.     

Potential of Pteris vittata to Remove Tetracycline Antibiotics from Aquatic Media

The role of combined arsenic and antibiotics pollution in the environment has recently gained more attention. In this study, a new approach to eliminate tetracycline antibiotics (TCs) from water, via the fern species Pteris vittata (L.), an arsenic hyperaccumulator, was investigated. The encouraging results showed that more than half of the TCs could be removed from the water solution (with the starting concentration of TCs about 1.0 mg kg^?1 respectively) after one day of treatment. No TCs (less than 0.01 mg kg^?1) were detected in the solution after five days of treatment. The results showed that Pteris vittata has high ability to eliminate TCs, which makes it suitable for practical application. Further research found that TCs concentrations were very low in both the roots and the pinnae of Pteris vittata, which indicates that accumulation in the fronds is not the main removal mechanism and that degradation in the fronds might be the main cause. Present results provide a feasible method for simultaneous removal of arsenic and TCs from livestock-polluted wastewater. However, more research work should be done before any real-world application is made.     

条纹短攀鲈的交配习性和筑巢生境

条纹短攀鲈栖息于静止、植被茂密、靠近稻田和池塘边缘的浅水中。本文研究了它在泰国稻田和小池塘两种生境中的繁殖特征。与池塘相比,稻田筑巢地的pH值、溶解氧的含量和温度较高,而电导、溶解的固体物浓度较低,水也较浅。稻田中的种群密度低于池塘。雄性个体的体重和体长均大于雌性个体,且其体重与体长和体宽正相关,但雌性个体的体重仅与体长正相关;泡巢的面积与雄性个体的体长和重量均不相关。繁殖期间,条纹短攀鲈雌、雄个体交尾多次。每次交尾产卵3.74±1.02(Mean±SD)粒,每个繁殖季节交尾84±12.97次;在一个持续178±51.17min的产卵时段里,条纹短攀鲈平均产卵314±109.77粒。鱼苗孵化需30.75±0.55h,2日龄个体的大小平均为3.21±0.29mm。     

Rehabilitation of a tailing dam at Shimen County, Hunan Province: Effectiveness assessment

This study was conducted to assess the effectiveness of phytoremediation on a tailing dam located in Shimen County, Hunan Province. Quadrat survey method was employed to investigate and sample the dominant plant species growing on the rehabilitated tailing dam. The fertilities of the soils were assessed, and concentrations of arsenic and other heavy metals in the plant and soil samples were measured. The results showed that no difference was found on the effect of soil capping with top and non-topsoils for rehabilitation of plants on the tailing dam. After rehabilitation, stable vegetation coverage types were established, 39 plant species were found to grow on the tailing dam, and the minimal area for plant communities was 30 m². The dominant plant species were planted Pteris vittata and natural colonizing Miscanthus sinensis. The contents of organic matter, nitrogen and phosphorus in the soils were low, while the potassium content was at a middle level; however, plots where Legumina plants grew were found to have higher level of nitrogen and phosphorus in the growing soils. Arsenic (As) and Cadmium (Cd) concentrations in the soils were 8 and 7 times of the grade III value of the National Standard for Soil Quality (GB15618-1995), respectively; while in tailings these were 81 and 68 times. The available As concentration in the soils ranged as 3.7–29.5 mg kg^?1, whereas the available As concentration in tailings was as high as 61.1 mg kg^?1. Concentrations for most of the heavy metals were in the normal range of terrestrial higher plants, except As and Cd in P. vittata and M. sinensis, and As in the roots of M. sinensis. It is concluded that phytoremediation project has reduced the ecological and health risks caused by the tailing dam to the ambient environment. However, the plants growing on the tailing dam which contained high As and Cd should be kept from entering into food chain in order to protect the health of local residents.     

Arsenate reductase activity in roots from the arsenic hyperaccumulator Pteris vittata utilizes both glutathione and dithiothreitol as reductants

Abstract

The role of glutathione and dithiothreitol as reductants supporting arsenate reductase activity in root extract from the arsenic hyperaccumulator Pteris vittata was examined. The two reductants in combination enhanced arsenate reduction in vitro more than glutathione alone. The implications of these results for in vivo arsenate reduction are discussed.     

Positional Shift Between the Vegetative Nucleus and the Generative Cell in Amaryllis Pollen Tube

A modified technique, FITC-tubulin immunofluorescence and DAPI localization to demonstrate simultaneously both the generative cell (GC) and the vegetative nucleus (VN) in the pollen tube under ultra-violet excitation, was developed sucessfully. During the germination of the pollen tube of Amaryllis vittata Ait. the GC and the VN, either being the first one, entered the tube within the first 1—2 h from the pollen grain. However, before the time of GC division, the VN was always positioned distally near the tip of the tube. In case when the GC entered the tube first, then the VN must have a positional shift in order to pass over the GC. The detail processes of positional shift between the GC and the VN were observed. Three basic processes were demonstrated: 1. The anterior end of the VN first reached the vicinity of the posterior attenuated extension of the GC about 2 h following germination forming a temporal physical association. Sometimes their both ends could be inserted into one another for certain extent. 2. The whole VN moved forward and contacted in parallel with the GC until they became twisted together and 3. The VN passed over the GC and greatly elongted lengthwise. Its posterior part became inserted into the anterior end of the GC. The behavior of positional shift between the VN and the GC in the pollen tube seems to be an adjustment of their diameters to fit the narrow tube. A conclusion may be drawn that the rate of movement between the VN and the GC was apparently different during the passage through the tube. Such difference may presumably be accompanied by the independent motive mechanism and structural difference between the VN and GC themselves, which provide their motive force for movement in the tube.