扁担塘螺类生产力的研究Ⅰ.铜锈环棱螺的周年生产量

１９９６—１９９７年对扁担塘螺类优势种之一铜锈环棱螺进行了周年研究,结果表明其种群含四个年龄组,其中１９９６年组生长最快,其带壳湿重瞬时生长率为４．１５,去壳干重瞬时生长率为３．４０。采用瞬时生长率法测算其周年生产量为：带壳湿重,１５．７７ｇ·ｍ－２·ａ－１;去壳干重,０．８６２４ｇ·ｍ－２·ａ－１。Ｐ／Ｂ系数基本一致,分别为０．５０,０．５１。铜锈环棱螺的生产量的去壳干重（Ｗｄ,ｇ·ｍ－２·ａ－１）和带壳湿重（Ｗｗ,ｇ·ｍ－２·ａ－１）满足下列关系：Ｗｗ＝１７．２０Ｗｄ。     

武汉东湖铜锈环棱螺种群变动和生产量的初步观察

本文报道了东湖环棱螺的种群密度、年龄结构、种群增长率和生物量、生产量、P/B系数及其在不同湖区中的季节变化;用指数生长模型计算种群增长率。以累计总增长的方法估算种群生产量。研究结果表明,水果湖区铜锈环棱螺年平均生物量为554.37克·米-2,累计生产量为604.99克·米-2·年-1,P/B系数为1.09;郭郑湖区平均生物量为286.74克·米-2,生产量为308.99克·米-2·年-1,P/B系数为1.08。本文还对影响铜锈环棱螺的种群变动和生产量的生态因子作了扼要的分析。       

武汉东湖湖球蚬种群动态及生产力的研究

1999年 6月至 2 0 0 0年 5月对武汉东湖湖球蚬进行了周年研究。湖球蚬年均密度和生物量分别为 10 0 2ind /m2 和12 1g/m2 ,密度和生物量的高峰分别出现在 4月 (2 97ind /m2 )和 3月 (4 3 8g/m2 ) ;湖球蚬为一年一代 ,其种群含有 3个年龄组 ,其中 1999年龄组占绝对优势。利用瞬时增长率法和体长频率法计算湖球蚬的周年生产量为带壳湿重4 2 79g/m2 ,去壳干重 2 4 4g/m2 ,P/B系数为 3 5 5。同时湖球蚬的生产力动态也被研究 ,结果表明其生产量累积过程主要发生在春季和秋季。     

稻田养殖铜锈环棱螺繁殖与仔螺生长特性

为阐明稻田养殖模式下铜锈环棱螺的繁殖特点及仔螺的生长规律, 于2019年5—11月对稻田养殖的铜锈环棱螺进行逐月采样分析。研究结果表明, 稻田养殖铜锈环棱螺的产仔高峰期为6月, 仔螺的产出规律为2个月1个周期。最小繁殖体重为0.9 g, 最小繁殖月龄为2月龄。不同体重规格的性成熟雌螺, 其怀胚量与体重呈显著正相关, 随体重增加, 怀胚量呈显著增加的趋势。不同体重组间, 体重为1.00—3.99 g的铜锈环棱螺间的怀胚量没有显著差异, 而其他各体重组间均存在显著差异。仔螺生长特性, 6月和7月为铜锈环棱螺仔螺的快速生长期, 壳高相对增长率分别为47.95%和36.99%, 体重相对增长率分别为180.60%和128.43%。铜锈环棱螺仔螺壳宽、壳口宽与壳高呈正相关的线性关系, 壳高和体重呈正相关的幂函数关系, 壳高-体重拟合方程为W=0.0005H2.785, 壳高生长方程为H_t=19.368/(1+3.608e–1.056t), 拐点壳高为9.684 mm, 拐点月龄为1.215月, 最大月增高5.113 mm。体重生长方程为W_t =2.012e–5.051exp(–0.753t), 拐点体重为0.740 g, 拐点月龄为2.151月, 最大月增重0.557 g。综上, 稻田养殖铜锈环棱螺的产仔高峰期为6月, 2月龄达到性成熟, 6月和7月是仔螺的快速生长期。     

铜锈环棱螺繁殖和生长的初步研究

作者于1963年3月至1964年6月间对武昌东湖的铜锈环棱螺的某些生态学问题进行了初步研究：自然种群中铜锈环棱螺的性比为1：1。成熟雌螺全年怀胚,月平均怀胚数以5月初最高,7、8、9月最低,生活于池塘中的雌螺的怀胚数又高于湖泊中相应壳高组雌螺的怀胚数。生殖季节自4月中旬至11月底,其中以6月份产螺达高峰,其临界水温为16—18℃,最适水温在26℃左右。雌螺生长至壳高15—16毫米开始生殖。在自然种群中,每一雌螺每年平均产螺49．7个。雌螺所产仔螺的大小与年龄有关。对铜锈环棱螺的生长规律,提出了有关方程式。     

铜锈环棱螺(Bellamya aeruginosa)对藻华水体中浮游动物群落的影响

本文通过围隔试验研究了淡水腹足纲动物铜锈环棱螺(Bellamya aeruginosa)对藻华水体中浮游动物群落的影响。实验根据铜锈环棱螺生物量设置了高、中和低3个密度组和一个不投放螺的对照组。分别于试验开始后0、3、7、11、15、23、31、46和61 d采集样品并计数浮游动物的种类和数量。结果表明:试验期间共鉴定出浮游动物33属52种,其中原生动物15种、轮虫28种、枝角类6种、桡足类3种;桡足类无节幼体、晶囊轮虫(Asplanchra)、多肢轮虫(Polyarthra)和臂尾轮虫(Brachionus)为浮游动物优势类群;主响应曲线分析显示,所有处理组中的浮游动物群落均与对照组存在显著差异;铜锈环棱螺的存在显著减少了有壳肉足虫、砂壳纤毛虫和轮虫种群数量,其中丰度降低最多的为螺形龟甲轮虫(Keratella cochlearis)、曲腿龟甲轮虫(Keratella valga)和砂壳虫(Difflugia sp.),在高密度组中的数量分别由试验开始时的481、545.3和359.7 ind·L~(-1)下降至试验结束时的0.1、0.1和9.2 ind·L~(-1);铜锈环棱螺的存在还导致高密度组中剑水蚤(Cyclops sp.)的数量由试验开始时的46.4 ind·L~(-1)增加至试验结束时的420.1 ind·L~(-1)。这些结果说明,铜锈环棱螺的存在显著影响了藻华水体中浮游动物的群落动态,而这些影响更多的是来自于铜锈环棱螺的间接影响而不是直接滤食。     

三峡库区马尾松人工林细根生产和周转

2011年3-12月,采用连续根钻法和分解袋法,研究了三峡库区20年生马尾松人工林细根的季节动态,计算了细根的年生产量和周转率.结果表明:三峡库区马尾松人工林细根(＜2 mm)年均生物量为146.98 g·m-2,其中活细根年均生物量(102.92 g·m-2)远大于死细根生物量(44.06 g·m-2);不同径级细根现存量的时间动态不同,＜1 mm根系季节动态较为明显,整体呈单峰型曲线;马尾松人工林细根(＜2 mm)的年生产量为104.12 g·m-2·a-1,年周转率为1.05 a-1,其中＜1 mm和1～2 mm的年生产量分别为58.35和45.77 g·m-2·a-1,周转率为1.41和0.69 a-1.     

锌胁迫对铜锈环棱螺致死率、富集性、CAT和SOD活性的影响

以浙江省温州市瓯海茶山某河内的铜锈环棱螺Bellamya aeruginosa为受试生物,研究了不同浓度Zn2+胁迫下,铜锈环棱螺的致死效应、铜锈环棱螺对锌的富集性以及锌对铜锈环棱螺体内的过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性的影响.结果表明Zn2+对铜锈环棱螺具有较大的毒害影响.当Zn2+浓度达到3.0 mg/L时,就会引起个别铜锈环棱螺死亡,死亡率为2.66％.随着Zn2+浓度的增大(0.3 mg/L到2.4 mg/L)和处理时间的增加(2d到8d),除个别组外,铜锈环棱螺对锌的累积量均随之上升,具有一定的时间效应和剂量效应.铜锈环棱螺在锌胁迫下,肝胰腺的CAT和SOD活性受到较大的影响.当Zn2+浓度较低时,CAT和SOD活性均有较大的升高,但当Zn2+浓度较高时,CAT和SOD活性则受到一定的抑制.     

淡水螺类去壳干重和无灰干重的换算方法

软体动物的生物量常用带壳湿重表示,然而外壳的主要成分是碳酸钙,不宜计为生物量,去壳干重和无灰干重相对更接近真实生物量,但其测量过于繁琐,因此有必要建立一套简单易行的方法对这2种干重生物量进行换算.选择长江流域常见的6种淡水螺类（环棱螺、长角涵螺、纹沼螺、大沼螺、方格短沟蜷和萝卜螺）,对其螺壳的5个形态参数和带壳干湿重与去壳干重和无灰干重的关系进行了研究.结果表明：这6种螺类的5个形态参数与去壳干重和无灰干重的回归关系均为指数式（y=ax^b）,其中,壳宽和壳长的换算效果（预测值与实测值间的百分误差率均值分别为22.0%和22.5%）好于其他参数;带壳湿重可通过方程直接换算为去壳干重和无灰干重（百分误差率均值为21.7%）.从概念的内涵和换算误差表明,无灰干重是表示螺类生物量的最适参数.     

保安湖扁担塘螺类生产力的研究 Ⅲ.长角涵螺的周年生产量

采用三种方法对扁担塘长角涵螺的周年生产量进行了测算 ,结果表明 ,三种方法得到的生产量及P/B系数吻合较好。生产量的带壳湿重和去壳干重分别是 :体长频率法 ,2 .0 88g·m 2 ·a 1 ,0 .1 0 3g·m 2 ·a 1 ;Allen曲线法 ,2 .1 2 2g·m 2 ·a 1 ,0 .1 0 6g·m 2 ·a 1 ;瞬时生长率法 ,2 .2 73g·m 2 ·a 1 ,0 .1 1 4g·m 2 ·a 1 。对应的P/B系数为 4.3 ,4.3 ,4.0。     

(n-7) and (n-9) cis-Monounsaturated fatty acid contents of 12 Brassica species

cis-Vaccenic acid or cis-11-octadecenoic acid, a C18:1 (n-7) isomer of oleic acid (C18:1 (n-9)) has been found in several oilseeds. It is synthesized from palmitic acid (C16:0) via production of C16:1 (n-7) by a Delta9 desaturase and elongation by an elongase giving C18:1 (n-7). In this study, the fatty acid composition of 12 Brassica species was analyzed by GC-FID and confirmed by GC-MS. All species contained C18:1 (n-7), C20:1 (n-7) and C22:1 (n-7) fatty acid isomers, suggesting that C18:1 (n-7) was elongated. The levels of these fatty acids varied according to the species. C18:1(n-7)) represented from 0.4% to 3.3% of the total relative fatty acid contents of the seeds. The contents of C20:1(n-7) and C22:1(n-7) levels were lower than C18:1(n-7) contents; the relative fatty acid composition varied from 0.02% to 1.3% and from below the limit of detection to 1.3% for C20:1 (n-7) and C22:1 (n-7), respectively. The ratios of (n-7)/(n-9) ranged from 2.8% to 16.7%, 0.6% to 29.5% and 0% to 2.6% for C18:1, C20:1 and C22:2, respectively. Using statistical similarities or differences of the C18:1 (n-7)/(n-9) ratios for chemotaxonomy, the surveyed species could be arranged into three groups. The first group would include Brassica napus, B. rapa, and B. tournefortii with Eruca sativa branching only related to B. napus. The second group would include B. tournefortii, Raphanus sativus and Sinapis alba. The last group would include B. juncea, B. carinata and B. nigra with no similarity/relationship between them and between the other species. Results suggested that the level of C20:1 (n-7) influenced the levels of all monounsaturated fatty acids with chain length higher than 20 carbons. On the other hand, palmitoleic acid (C16:1) levels, C16:1 being the parent of all (n-7) fatty acids, had no statistically significant correlation with the content of any of the fatty acids of the (n-7) or (n-9) family.     

First record of a nematode Metastrongyloidea (Aelurostrongylus abstrusus larvae) in Achatina (Lissachatina) fulica (Mollusca, Achatinidae) in Brazil

Achatina (Lissachatina) fulica was introduced in Brazil in the 1980s for commercial purposes (“escargot” farming) and nowadays, mainly by human activity, it is widespread in at least 23 out of 26 Brazilian states and Brasília, including the Amazonian region and natural reserves, where besides a general nuisance for people it is a pest and also a public health concern, since it is one of the natural intermediate host of Angiostrongylus cantonensis, ethiological agent of the meningoencephalitis in Asia. As Brazil is experiencing the explosive phase of the invasion, the Laboratório de Malacologia do Instituto Oswaldo Cruz/Fiocruz has been receiving samples of these molluscs for identification and search for Angiostrongylus cantonensis and Angiostrongylus costaricensis larvae. While examining samples of A. fulica different nematode larvae were obtained, including Aelurostrongylus, whose different species are parasites of felids, dogs, primates, and badger. Morphological and morphometric analyses presented herein indicated the species Aelurostrongylus abstrusus, as well as the occurrence of other nematode larvae (Strongyluris-like) found in the interior of the pallial cavity of A. fulica. This is the first report in Brazil of the development of A. abstrusus infective larvae in A. fulica evidencing the veterinary importance of this mollusc in the transmission of A. abstrusus to domestic cats. Since the spread of A. fulica is pointed out in the literature as one of the main causative spread of the meningoencephalitis caused by A. cantonensis the authors emphasize the need of sanitary vigilance of snails and rats from vulnerable areas for A. cantonensis introduction as the port side areas.     

Rh(I) complexes containing tris(pyrazolyl)amine and bis(pyrazolyl)amine ligands: synthesis and NMR studies

The tris(pyrazolyl)amine ligands: tris[2-(1-pyrazolyl)methyl]amine (tpma), tris [3,5-dimethyl-1-pyrazolyl)methyl]amine (tdma), tris[2-(1-pyrazolyl)ethyl]amine (tpea), tris[2-(3,5-dimethyl-1-pyrazolyl)ethyl]amine (tdea) and bis(pyrazolyl)amine ligands: bis[2-(1-pyrazolyl)ethyl]amine (bpea) and bis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]amine (bdea) react with [RhCl(cod)]₂ in presence of NaBF₄ (tpma, tdma and bdea) or AgBF₄ (tpea, tdea and bpea) to lead to [Rh(cod)L] (BF₄) (L=tpma (1), tdma (2), bdea (3), tpea (4), tdea (5) and bpea (6)). These complexes have been characterised by elemental analyses, conductivity, IR, ¹H and ¹³C NMR spectroscopy and liquid mass (with electrospray) spectrometry. The ¹H NMR spectra of 1, 2 show the presence of two isomers in solution in a 3:1 ratio (coordination κ² or κ³ type) in a thermodynamic equilibrium. The steric bulk of cyclo-octa-1,5-diene causes it to prefer the κ² mode of bonding as majority. Similar to previous published results, complexes 4 and 5 exist in a sole form in solution (probably κ² isomer). Finally, the complexes 3 and 6 are fluxional. A NMR study shows that this fluxional process is not frozen at 183 K.     

Ent-3,4-seco-labdane and ent-labdane diterpenoids from Croton stipuliformis (Euphorbiaceae)

From a methanolic extract of the leaves of Croton stipuliformis, three ent-3,4-seco-labdanes (1-3) and an ent-labdane (4) together with the known compounds 6-hydroxynidorellol (5), maravuic acid, and sitosterol were isolated and identified from their spectroscopic data. The absolute stereochemistry of compound 4 was determined by application of Mosher's method in the NMR tube.     

Fossil frogs (Anura) from Shanwang (Middle Miocene; Shandong Province, China)

The early middle Miocene biota from the Shanwang locality in eastern China is one of the most diverse and well preserved in the world. This overall richness contrasts with its low diversity of anuran amphibians. The most abundant anurans are representatives of the family Ranidae, which remains the dominant group in the extant anuran fauna of China. Besides Rana basaltica Young, some other ranids can be recognised at the locality, and are clearly distinguishable from R. basaltica based on their larger size and different proportions. Ranids are also represented by a developmental series of tadpoles, ranging from approximately Nieuwkoop-Faber (NF) stage 43 to a metamorphosing tadpole of NF stage 57. This is the first known developmental series of fossil non-pipoid Anura outside the Pelobatidae. In addition to the ranids, Bufo shandongensis nov. sp. (replacement name for B. linquensis), represented by one of the earliest known articulated bufonid skeletons, is described and illustrated. Another large toad, Macropelobates linquensis (Yang) nov. comb., is re-described; it can be assigned to the Pelobatoidea, with a possible relationship to the Scaphiopodidae, and can be considered, based on the presence of a large spade, a tibiofibula shorter than the femur, and a short astragalus and calcaneus, to be the earliest known anuran burrower.     

Epizootiological studies of Amblyospora camposi (Microsporidia: Amblyosporidae) in Culex renatoi (Diptera: Culicidae) and Paracyclops fimbriatus fimbriatus (Copepoda: Cyclopidae) in a bromeliad habitat

The epizootiology of Amblyospora camposi was studied in a natural population of Culex renatoi, a bromeliad-inhabiting mosquito, and its intermediate host, Paracyclops fimbriatus fimbriatus, over a 2-year period. Twenty Eryngium cabrerae plants were sampled monthly from January 2003 to January 2005 and the prevalence of A. camposi in P.f. fimbriatus and Cx. renatoi populations was determined. The monthly prevalence rates of meiospore infections in Cx. renatoi larvae never exceeded 5.5% and was detected in 50% of the monthly samples. Meiospores were available in plants over the course of the study at a mean concentration of 2 x 10(4) meiospores/ml. Within each plant the parasite was maintained by horizontal transmission. P.f. fimbriatus with vegetative stages and mature spores were found regularly in bromeliads suggesting efficient meiospore infectivity to field copepod populations. The mean concentration of spores from copepods found in plants was 8 x 10(2) spores/ml. Infections in copepods were detected in 54% of the monthly samples with a prevalence rate ranging from 0.55 to 17.4% and an overall average of 5.1%. Vegetative stages in fourth instar mosquito larvae (probably derived from the horizontal pathway via spores formed in copepods) were detected in 12.5% of the monthly samples with an overall prevalence rate of 1.1%. Infections in female and male adults were detected in 20.8% of the monthly samples with an overall average of 4.1% and 6.8%, respectively.     

Cossidae of the socotra archipelago (yemen)

The faunistic composition of the family Cossidae (Lepidoptera) of the Socotra Archipelago is revised. Five species are recognized, including two new species (Mormogystia brandstetteri and Meharia hackeri), and dubious identifications and records are discussed. Adults and genitalia are illustrated and bionomic details, DNA barcodes and a synonymic checklist for Socotran cossids are provided. A review of their distribution reveals that at least 80 percent of Socotra's cossids are unique to the archipelago, which is renowned for its endemism. A checklist listing all the species from generas Meharia, Mormogystia, Aethalopteryx, Azygophleps, as well as the synonymy and distribution is provided.     

Effect of entomopathogenic nematodes on Plectrodera scalator (Fabricius) (Coleoptera: Cerambycidae)

Entomopathogenic nematodes were screened for efficacy against the cottonwood borer, Plectrodera scalator (Fabricius). Steinernema feltiae SN and S. carpocapsae All killed 58 and 50% of larvae, respectively, in filter paper bioassays but less than 10% in diet cup bioassays. S. glaseri NJ, S. riobrave TX, and H. indica MG-13 killed less than 10% of larvae in both assays. H. marelata IN was ineffective in the diet cup bioassay and killed 12.9% of larvae in a filter paper bioassay. The nematode isolates we tested are not suitable for use as biological control agents against P. scalator.