Fungal macrolides: Structure determination and biosynthesis of achaetolide,a lactone from Achaetomium cristalliferum

The structure of a new ten-membered lactone, achaetolide, isolated from cultures of Achaetomium cristalliferum is deduced from its mass and NMR spectra and from the study ofsomederivatives. The ¹³C NMR spectra of achaetolide enriched with [1-¹³C], [2-¹³C] and [1, 2-¹³C] acetate established its formation from eight intact acetate units via a precursor octaketide chain.     

Biogas-plant effluent as an organic fertiliser in fish polyculture

Biogas-plant effluent collected from a KVIC model biogas-plant fed on cattle waste was utilised in fish polyculture. Biogas-plant effluent was applied at 0·15% concentration at 3-day intervals. The growth rate of Labeo rohita was 4·52 ±0 ·75 g fish⁻¹ day⁻¹, of Cirrhina mrigala 3·36 ± 0·48 g fish⁻ day⁻¹ and of Cyprinus carpio was 1·82 ± 0·41 g fish⁻¹ day⁻¹. Total fish production was 13·44 ± 0·77 kg 0·002 ha⁻¹ year⁻¹ (6653 kg ha⁻¹ year⁻¹) without any supplementary fish-feed.     

Investigation of methanogen population structure in biogas reactor by molecular characterization of methyl-coenzyme M reductase A (mcrA) genes

The methanogen community in biogas reactor running on cattle dung was investigated in two different seasons; summer (April, 36 °C) and winter (December, 24 °C), in the year 2004 by a culture-independent approach. Community structure was determined by phylogenetic analyses of 343 and 278 mcrA clones belonging to summer and winter month libraries, respectively. In summer month’s library, 41.7% clones were affiliated to Methanomicrobiales, 30% to Methanosarcinales, 19% to Methanobacteriales, 5% to Methanococcales and a total of 4.3% clones belonged to unclassified euryarchaeotal lineages. In winter month’s library, Methanomicrobiales encompassed 98.6% clones, and Methanobacteriales included 1.4% of total clone diversity. Biogas plant performance data collected during the winter month indicated significant reduction in daily biogas produced as compared to summer month because of lowering in ambient temperature and associated shift in microbial community. Results from this molecular study showed the existence of highly diverse and complex methanogens communities present in biogas plant.     

内蒙古典型草原马粪分解过程中节肢动物群落的季节动态变化

地面节肢动物作为陆地生态系统的重要组成部分, 在大型食草动物粪便分解中扮演着重要角色。当前动物粪便中节肢动物群落研究主要集中在粪便类型和微生境的作用, 而季节或气候状况对粪便中节肢动物群落影响的研究较少。本研究在内蒙古典型草原区, 采用野外人工堆置方法, 研究不同季节马粪中节肢动物群落的组成和多样性特征, 并分析了节肢动物各类群多度与环境因子的关系。结果表明: (1)春夏秋3个季节马粪的初始含水量不存在显著差异(P > 0.05); 夏季马粪初始有机质含量显著地低于春季和秋季(P < 0.05); 马粪初始pH在秋季显著地低于春季和夏季(P < 0.05)。(2)在马粪分解第3 d和第360 d, 秋季马粪中节肢动物群落多度和类群数显著高于春季(P < 0.05); 在粪块分解第3 d和第7 d, 秋季马粪中粪金龟子群落多度和物种数显著高于夏季(P < 0.05); 在分解第3 d和第7 d, 秋季马粪中隐翅虫群落多度和属数显著高于春季和夏季(P < 0.05)。研究表明, 分解早期粪的有机质含量和含水量对马粪中节肢动物群落组成影响较大, 而分解后期节肢动物群落组成主要受土壤温度和湿度的调控。     

荒漠草原马粪中粪金龟子组成及分解作用

2007年4-10月,采用野外和室内实验相结合的方法,研究了荒漠草原马粪中的粪金龟子群落组成和对马粪分解的影响.共捕获粪金龟子13528头,隶属于3科4属26种,优势种为符号蜉金龟(Aphodius comma),占总捕获量的88.5%,不同季节粪金龟子群落组成明显不同;在鲜马粪中活动的粪金龟子以粪居型蜉金龟为主,在鲜马粪堆置3d时种数和个体数达到最高,6d后全部离开;马粪经过136 d分解,残留率为52.5%,残留粪样中氮和磷释放较慢,钾释放较快;结合室内分解实验的结果,认为粪金龟子主要通过在马粪中活动对其分解产生影响,并与风蚀作用成为荒漠草原马粪块破碎的重要动因,主要发生在春季和秋季.     

A functional classification for analysis of the structure of dung beetle assemblages

Abstract. 1. Regional scarabaeid dung beetle assemblages in southern Africa may contain over 100 species, ranging in live weight from 10 mg to 10 g. These show a wide variety of dung-use and reproductive strategies.
2. To facilitate analysis of these diverse assemblages, a system of classification analogous to guilds is proposed. Scarabaeid dung beetle species are allocated to one of seven functional groups (FGs) according to the way they use and disrupt dung. Each group therefore contains a set of species which are functional analogues of each other. This classification provides a conceptual framework within which to analyse the structure of dung beetle assemblages and the interactions between dung beetles and other dung-breeding species such as coprophagous flies.
3. There is a clear hierarchy of functional groups in their ability to compete for dung. Competitively dominant groups such as the large ball rollers (FG I) and fast-burying tunnellers (FG III) are mostly large, aggressive beetles which rapidly remove dung from the pad. The smaller ball rollers (FG II) are also effective competitors for dung. Subordinate groups are those which bury dung slowly over many days (FG IV and V) and those which breed inside the pad (FG VII, endocoprids). Kleptocoprids (FG VI) breed in dung buried by other beetles and so are not part of the hierarchy.
4. The use of this classification is illustrated by reference to three contrasting assemblages of dung beetles in a summer rainfall region of southern Africa. The potential of these beetles for biological control of dung-breeding flies is discussed.     

Matter transfer and land use by cattle in a dehesa ecosystem of Central Spain

The transfer of matter by cattle in a dehesa patureland in Central Spain has been quantified by mapping the distribution of dung and different types of cattle behaviour in several areas distinguished by their geomorphological position, vegetation structure and management regime.Cattle show a clear preference for feeding and dung depositing in the low parts of the estate. This leads to an increase in the productivity and a rapid recycling of nutrients in the pasture communities of these areas. Comparing the relative importance of both processes in each vegetational unit, dung accumulation is greater in the higher zones, while in the lower areas biomass consumption is more important. This means that movement of matter by cattle tends to favour the higher ground, in a contrary direction to the downward leaching of nutrients and related processes. In the studied dehesa, this phenomena represents an exploitation factor of the lowland areas, which maintains productive pasture communities more immature in successional terms, by the higher woodland areas, less grazed and with low turnover. This result supports claims made in other studies that animal activity — assessed in our case by the relative impacts of herbivory and dung depositions — connect adjacent ecosystems and thus tends to improve the net energy balance of the more successionally mature part of the system.Livestock movements differ in their spatial pattern during different periods of the year: dispersing in spring and becoming more concentrated and predictable during winter. The clear seasonal differences of herbaceous production in Mediterranean climates and the management activities (basically ploughing, tree pruning and fodder supply) are the main causes of this pattern.Abbreviations PI= Preference Index     

Seedling establishment after endozoochory in disturbed and undisturbed grasslands

Local plant community composition and structure may be largely influenced by germination and seedling establishment from seeds dispersed in animal dung, through seed input, gap creation and nutrient enrichment. With an experimental approach we assessed (1) what the effect is of dung deposition on the number of seedlings in the plant community 3 months and 1 year after dung deposition, (2) what the effect is of this seedling establishment on the local plant community characteristics such as species richness and (3) if this effect interacts with large-scale soil disturbance which removes the close canopy, such as sod-cutting. Viable seeds of monocotylous species were abundantly present in the dung, and dung deposition led to a higher number of monocotylous seedlings after 3 months. However, this effect was no longer significant after 1 year. Moreover, the proportion of viable monocotylous seeds that effectively established in the field after 3 months was less than 5%. A lower number of viable seeds of the less-dominant dicotylous species was dispersed in the dung but they had a higher cover and species richness after 1 year. This resulted in an increased total small-scale species richness and diversity after dung deposition through a decreasing dominance of monocotylous species. Sod-cutting had a pronounced effect on seedling emergence: viable seeds dispersed by dung had a higher probability of successful establishment when the dung was deposited in large gaps. This indicates that an increase of safe sites associated with disturbance strengthens the effects of seed dispersal and gap creation by dung deposition.     

Deposition and decomposition of cattle dung in forest grazing in southern Kyushu, Japan

This study monitored deposition and decomposition of cattle dung in a grazed young Chamaecyparis obtusa (an evergreen conifer) plantation in southwestern Japan, as a part of exploring the impacts of livestock in the forest grazing system. Animals defecated 10–19 times hd⁻¹ day⁻¹, producing feces of 2.2–3.5 kg DM and 33–73 g N per animal per day. The DM and N concentrations of feces ranged from 157–207 g DM kg⁻¹ and 14.8−23.1 g (kg DM)⁻¹, respectively. Occurrence of defecation was spatially heterogeneous, with feces being concentrated mainly on areas for resting (forest roads, ridges and valleys) and moving (forest roads and along fence lines). Decomposition of dung pats was considerably slow, showing the rates of 1.37–3.05 mg DM (g DM)⁻¹ day⁻¹ as DM loss. Decomposition was further slower on the basis of N release, 0.51–1.63 mg N (g N)⁻¹ day⁻¹, resulting in steadily increased N concentrations of dung pats with time after deposition. The results show that introduction of livestock into a forest (i.e., forest grazing) may limit nutrient availability to plants, by redistributing nutrients into areas with no vegetation (bare land and streams) and by establishing a large N pool as feces due to an imbalance between deposition and slow release, though further studies are necessary for investigating the occurrence of slow dung decomposition in other forest situations.     

降水量对川西北高寒草甸牦牛粪分解速率的影响

青藏高原高寒草甸的降水年际变化很大,而且在未来全球气候变化的背景下可能进一步增大.为了研究降水量变化对川西北高寒草甸牦牛粪分解的潜在影响,通过塑料膜覆盖(去除降水)、模拟额外增水(增水量为实际降水量的50％)和对照(野外无干扰情形)形成3种不同的水分处理.测定了牛粪的含水量、干重及氮磷含量,并统计了主要分解者(手捡法获取粪食性甲虫及其幼虫)的种类和数量.结果发现:覆盖处理显著地降低了牛粪含水量、牛粪中的粪食性甲虫数量与牛粪分解量,但增水处理并没有显著影响牛粪的分解进程,可能与实验期间降水量较高有关.在牛粪分解前期,粪食性甲虫数量与牛粪含水量之间正相关,而牛粪分解量与粪食性甲虫数量之间正相关,说明牛粪含水量的高低影响了粪食性甲虫数量,进而决定了牛粪分解量.但是,降水量的人为增加或减少均没有显著地改变牛粪中的全氮和全磷含量.总体上看,在高寒草甸的放牧生态系统中,降水量的减少将会降低牛粪的分解速率、延长牛粪分解过程,从而可能会降低生态系统的生产力水平.     

Influence of diet on the structure and function of the bacterial hindgut community of crickets

The effect of diets varying in carbohydrate and protein content on the structure and function of the hindgut microbiota of crickets was evaluated by determining bacterial densities, fermentation activity, and guanine plus cytosine (G + C) profiles of the DNA extracted from the microbial hindgut community. DNA isolated from the gut community was fractionated and quantified according to G + C content as a comprehensive, coarse-level measure of the composition and structure of the community. The bacterial densities measured by direct counts were not significantly different among the four diets. The crickets were initially reared in the laboratory on cricket chow, which resulted in a hindgut community dominated by bacteria with a G + C content between 32% and 57%. Crickets shifted to an alfalfa diet showed a similar hindgut community G + C profile, although microbial populations with DNA between 35% and 45% G + C were more abundant in alfalfa- than chow-fed crickets. The apparent complexity of the gut community was reduced in crickets fed beet-pulp and protein-based diets compared to those fed chow and alfalfa, and was dominated by populations with a low percentage G + C content. Hindgut communities in crickets fed pulp and protein diets also showed a decrease in hydrogen and carbon dioxide production, suggesting that these diets affected the biochemical activity of the hindgut community. The protein-based diet resulted in a decrease in the rate of evolution of volatile fatty acids, while the ratio of butyrate production to acetate and propionate production was significantly higher in these crickets. Our results show the emergence of a new microbial community structure concomitant with changes in microbial biochemical activity due to shifts in the cricket's dietary regime.     

上海地区葡萄种植园昆虫种群调查

葡萄是上海地区重要的经济水果,为探明上海葡萄种植园中昆虫种群组成,本研究在2017-2018年间,通过搜捕法、马氏网诱集法和黄色粘纸诱集法,对上海市嘉定区、奉贤区、青浦区、浦东新区、崇明岛进行了昆虫种群调查,共采集并鉴定昆虫7目65科123属182种,明确了上海地区葡萄种植园内主要害虫、天敌昆虫及环境昆虫的种类,并对上海葡萄园的昆虫种群结构和多样性进行了分析。     

麦田昆虫群落结构和变动的研究

通过田间调查,在Windows 98平台上利用Visual Basic6.0统计编程,系统研究了麦田害虫及其天敌从5月9日至6月2日的相对多度、物种丰富度、生态优势度、多样性指数和均匀度的变动。表明5麦田是相继作物害虫的重要天敌源,应保护利用。     

九华河水生昆虫群落结构和水质生物评价价

1989年6月、8月、10月对安徽九华河水系3、4、5级支流5个基点采用扫网、刷石等综合定性取样法,共采得水生昆虫9目、49科、86属、124种,计6445头。其中:毛翅目12科、41种;蜉蝣目10科、26种;鞘翅目5科、16种;双翅目7科、14种;襀翅目4科、9种;蜻蜓目5科、8种;半翅目4科、5种;广翅目1科、3种;鳞翅目1科、2种。3、4级支流Shannon多样性指数大于4,种丰富度大于60,水质极清洁;5级支流Shannon多样性指数大于3,种丰富度29,水质较清洁。3级支流以毛翅目,蜉蝣目为主,科级水平生物指数最高(2.58—2.59);4级支流以毛翅目、蜉蝣目和双翅目为主,多样性指数最高(5.54);5级支流以蜉蝣目、双翅目为主。本文还根据“河流连续概念”对各支流水生昆虫群落结构、季节性变化、毛翅目取食功能类群与支流级别的关系等作了初步分析,并提供了必要的物理、化学参数。     

花椒园昆虫群落结构及时间动态的聚类分析

【目的】通过调查花椒园生态系统中昆虫群落的组成,分析其动态及其时空特征,评价花椒园昆虫各亚群落间的相互关系,旨在为花椒园立体农业的构建及其害虫的生态调控提供科学依据。【方法】采取5点取样法,调查记录枝条和树干上的昆虫种类和数量。同时采用糖醋液诱集、黄板诱集、滴水黄盘诱集、目测和网捕等方法调查。利用群落特征指数对群落的基本特征进行分析,采用系统聚类方法对各群落特征指数时间动态进行分类。【结果】通过对花椒园昆虫群落的系统调查,共查到花椒园昆虫(包括蜘蛛类)359种,隶属19目148科。半翅目相对丰盛度最高,为0.3036,其次为蜘蛛类,其相对丰盛度为0.2033。在分析花椒园昆虫群落结构的基础上,对花椒园昆虫群落进行聚类分析。结果表明,对不同时期的总群落、亚群落进行模糊聚类,其结果显示:总群落的24次调查结果可以聚为9类,阈值T=0.98,3月20日,5月20日,3月30日,4月28日,4月10日,10月10日各分为一类,10月20日、10月30日、11月12日为一类,其余归为一类;天敌亚群落调查结果聚为7类,T=0.95,3月20日,5月30日,11月12日,3月30日各自归为一类,4月20日、4月28日归为一类,4月10日、10月30日归为一类,其余归为一类;非天敌亚群落调查结果聚为9类,T=0.97,3月20日、3月30日、5月20日、6月20日、9月30日、10月10日各自归为一类,6月10日和6月30日归为一类,10月20日、10月30日、11月12日归为一类,其余归为一类。【结论】聚类结果反映了群落状况的季节差异,聚类交替现象反映了群落结构复杂性,聚类结果的复杂性反映了各时期的非生物因素对群落动态有较大影响。     

苹果生长前期昆虫群落空间结构分析

在苹果生长的前期 ,将苹果树分为 1 8个区 ,研究每个区立体空间中的昆虫群落结构。结果分析表明 :苹果树中昆虫 (及螨类 )共有 2 7种 ,其中植食性害虫 1 5种 ,种数占总量的 5 5 5 6% ,天敌昆虫 1 2种占 44 44% ;昆虫群落在树上、下、中及内外层差异大 ,而在东、南、西、北 4方位上差异小。通过频次比较的方法与 χ2 检验得出 :梨星毛虫IlliberispruniDyar、山楂叶螨TetrangchusviennensisZacher、顶梢卷叶蛾SpilonotalechriaspisMeyrich均符合负二项分布 ;采用聚集指标法计算得出 :梨星毛虫、山楂叶螨、顶梢卷叶蛾均为聚集型分布 ,另外 ,山楂叶螨的I值最大 ,聚集度最高。以上的研究为苹果园有害生物综合治理提供理论依据     

丹参田花期昆虫群落结构及多样性研究

为明确丹参田花期昆虫群落结构,本文采用马氏网对丹参花期的昆虫进行收集,分类鉴定后开展群落结构及多样性分析。结果表明,丹参花期共收集到昆虫5 438头,隶属于膜翅目Hymenoptera、双翅目Diptera、半翅目Hemiptera、鳞翅目Lepidoptera、鞘翅目Coleoptera、直翅目Orthoptera、脉翅目Neuroptera 7目52科,双翅目、膜翅目昆虫为优势类群,群落丰盛度、丰富度指数较高,Shannon-Wiener多样性指数、Pielou均匀度指数较为稳定,Simpson优势度指数较低,可见丹参田花期昆虫种群结构较为稳定。