不同种植模式花椒园昆虫群落的结构及稳定性

对云南昭通市4种不同种植模式花椒园（花椒-玉米-大豆园、花椒-大豆园、花椒-玉米园、花椒园）昆虫群落的组成和结构进行调查,采用群落特征指数和主分量分析法对不同种植模式花椒园昆虫群落特征及其稳定性进行了研究.结果表明：研究区花椒园共发现326种昆虫;与单一种植花椒园相比,间作套种作物花椒园昆虫群落的丰富度指数、多样性指数和均匀度指数均较高,而优势度指数较低;不同种植模式花椒园昆虫群落多样性指数值大小依次为花椒玉米大豆园>花椒大豆园>花椒玉米园>花椒园.花椒、玉米、大豆间作套种系统中昆虫群落的稳定性较好.     

Effects of decomposition on carcass attendance in a guild of carrion-breeding flies

Many forensically important calliphorids, sarcophagids and muscids (Diptera) oviposit or larviposit on corpses only during the early stages of decomposition, yet individuals may attend bodies throughout decay. A field study was conducted to investigate how patterns of carcass use and attendance by some fly species are affected by decomposition. Five fly traps were placed in the forest and baited with whole, fresh piglet carcasses. Piglets decomposed in traps throughout the experiment, and all were skeletonized within 6 days. Flies were trapped at both early and late decomposition stages, and the species and population structures of trap catches were compared. More flies attended carcasses early rather than late in decay. For all species, flies attending early were mainly gravid females, but few gravid females attended late in decay. No females ovi- or larviposited late in decay, whereas females of all fly species deposited offspring early in decay. The number of males trapped of each species correlated positively with the number of females with eggs at early development stages. Observations were made of fly predation by European wasps Vespula germanica Fabricius (Hymenoptera, Vespidae) and jumper ants Myrmecia pilosula Smith (Hymenoptera, Formicidae) throughout the experiment. There was a higher risk for smaller fly species of being killed following predator attack. Ants and wasps attacked smaller fly species, whereas only wasps attacked larger fly species.     

不同林分类型对昆虫群落多样性的影响

为研究近自然森林经营下的华北落叶松人工林不同林分类型对昆虫群落多样性的影响,以塞罕坝自然保护区内的华北落叶松纯林和混交林作为研究对象,对6种不同林分类型中的昆虫群落结构进行了研究。共获得昆虫标本9542头,隶属于7目,68科,187种,以双翅目、半翅目和鞘翅目为优势类群。研究结果表明:6种林分类型中的昆虫在物种和个体数上存在差异,相似性分析显示群落结构均不相似;群落多样性指数分析表明华北落叶松纯林和其它类型的混交林均具有较高的丰富度指数和多样性指数;主成分分析表明各林分类型中捕食性类群和寄生性类群是影响昆虫群落结构的主要因素,且捕食性类群和寄生性类群对植食性类群的控制作用较强;稳定性分析显示6种林分类型昆虫群落结构均具有较高的稳定性。     

吉林黑土区不同施肥处理对农田土壤昆虫的影响

为研究不同施肥处理与农田土壤昆虫群落之间的关系,对吉林黑土区不同施肥处理对农田土壤昆虫群落的影响进行了研究.在12个处理小区内,即（1）撂荒（不施肥、不耕作、不种植,ABAND）、（2）对照（种植、不施肥,CK）、（3）施氮肥（N）、（4）施氮磷肥（NP）、（5）施氮钾肥（NK）、（6）施磷钾肥（PK）、（7）施氮磷钾化肥（NPK）、（8）施氮磷钾化肥＋有机肥处理（有机N 和化肥N 的比例为2：1）（M1NPK）、（9）增加50 %用量化肥配施有机肥（1.5 MNPK）、（10）化肥配施秸秆（SNPK）、（11）玉米、大豆2：1轮作,施肥量同处理8（Rot）、（12）施氮磷钾化肥＋有机肥处理（有机N 和化肥N 的比例为1：1）（M2NPK）,共采集144个定点土壤样品.通过手捡法和改良干漏斗法（Modified Tullgren ）共获得土壤昆虫9922只（未知标本187只）,隶属9目48科.调查结果显示,12种施肥小区内,大型土壤昆虫个体数和类群数依次是：ABAND＞NP＞N＞1.5MNPK＞Rot.＞PK＞NK＞NPK＞M2NPK＞CK＞M1NPK＞SNPK,N＞NK＞ABAND=1.5MNPK＞NP=NPK＞PK＞CK=Rot.＞M2NPK=M1NPK＞SNPK;中小型土壤昆虫数依次是ABAND＞1.5MNPK＞PK＞M2NPK＞CK＞Rot.＞NPK＞SNPK＞NK＞NP＞N＞M1NPK,Rot.＞NPK＞ABAND=NP=1.5MNPK=PK=NK=M2NPK=CK=M1NPK=SNPK＞N.大型土壤昆虫个体数和类群数撂荒中分布最多,中小型土壤昆虫则分别在撂荒和轮作中分布最多.多样性分析表明,1.5MNPK处理中大型农田土壤昆虫组成最丰富,M1NPK处理中小型农田土壤昆虫组成最丰富;CK处理与其他11处理之间群落相似程度最小,Rot.与其他处理之间的群落相似程度较大.Kruskal- Wallis检验法分析表明,施肥对农田土壤昆虫分布影响极显著（X0.05（11）=10.25,p〈0.05）,反映出不同施肥对土壤生态系统内部环境,进而对土壤动物群落产生的影响.多元统计分析表明,轮作对土壤昆虫优势类群具有负向作用,而M2NPK则具正向作用.各种施肥对农田土壤昆虫影响不平衡,其中对农田土壤昆虫个体数影响最大,对中小型土壤昆虫均匀性影响最小.     

太湖湿地昆虫群落结构及多样性

为了探讨太湖湿地昆虫群落的结构和变化规律,对太湖湿地各生境样点昆虫群落进行了调查研究.调查共获得昆虫标本24968号,隶属于13目88科301属318种;半翅目、鳞翅目、鞘翅目和直翅目等为优势类群.各样点昆虫群落多样性指数和均匀度指数特征值为湿地恢复示范区＞渔阳山＞三山岛＞三洋村＞灵湖村,优势集中性指数的特征值比较为:湿地恢复示范区＜渔阳山＜三洋村＜三山岛＜灵湖村.各样点昆虫群落的多样性指数与均匀度指数和丰富度指数表现一致.在时间序列上渔阳山样点昆虫群落的多样性指数波动最小.昆虫群落的极点排序表明渔阳山和湿地恢复示范区样点昆虫群落是最相近的.主分量分析的结果显示太湖湿地昆虫群落主要受捕食性和植食性昆虫群落的影响.湿地恢复示范区样点昆虫群落内天敌昆虫比例偏低,降低了昆虫群落对外界扰动的缓冲能力.综合昆虫群落的各项分析结果发现渔阳山样点昆虫群落稳定性最高,三洋村样点昆虫群落稳定性最低.     

Morphological and genetic analysis of fish of a Carassius complex (Cyprinidae) in Lake Kasumigaura with reference to the taxonomic status of two all-female triploid morphs

The classification of the Carassius complex (Cyprinidae) including all-female triploids, called ginbuna in Japanese, is so confused that three sympatric morphs of crucian carp in Lake Kasumigaura are categorized into two different subspecies within a species. We examined them in order to explain the coexistence of more than one subspecies and determine the founder of the triploid lineages in the crucian carp fauna in the lake. Principal component analysis proved that the three sympatric morphs had a morphometric basis distinguishable from each other. Ploidy was determined by flow cytometry which showed triploids in two morphs and diploids in the other morph. Stepwise discriminant analysis using only meristic characteristics could separate the diploids from the triploids. Phylogenetic analysis using mitochondrial DNA inferred two lineages in which one was composed of a triploid morph and the other was a diploid–triploid mixture. Disagreement between the taxonomic status and the phylogenetic status is explicable by assuming that the triploids in the Carassius complex had independent origins leading to the different subspecies. C. auratus langsdorfii appears to show genetic complexities that traditional taxonomic classification can not unravel.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79 , 351–357.     

北京市延庆采砂迹地型湿地植被群落分类与演替分析

采用TWISPAN分析方法,对北京市延庆采矿迹地湿地40个样地51种植物进行了分类排序,将群落类型划分为7个类型,即茵陈蒿-狗尾草-黄花蒿群落、野艾蒿-茵陈蒿-尖叶胡枝子-狗尾草群落、野艾蒿-茵陈蒿-狗尾草-野大豆-苣荬菜群落、狗尾草-苍耳-黄香草木犀-虎尾草群落、狼拔草-野艾蒿-旋覆花-大籽蒿-芦苇群落、香蒲-芦苇-茭白-野大豆-鬼针草群落和竹节灯心草-褐穗莎草-稗群落;同时运用双变量主坐标分析(DPCoA)对51种植物进行了排序分析,研究结果显示研究区存在两种演替规律,即由喜湿旱生耐淹水植物演替为喜旱旱生植物和由湿地挺水植物向湿生植物演替两种类型.对于采砂基地型湿地植被恢复不仅恢复土壤营养条件,调控湿地水分条件也是十分关键的.研究结论将为采砂迹地型湿地恢复提供科学支持.     

Spatial variability in the amount of forest litter at the local scale in northeastern China: Kriging and cokriging approaches to interpolation

Litter is essential to promote nutrient cycling and maintain the sustainability of forest resources. However, its variability has not been sufficiently studied at the local scale. The prediction of litter amount using ordinary cokriging with Pearson correlation analysis (COK_P) and ordinary cokriging with principal component analysis (COK_PCA) was compared with that using ordinary kriging (OK) based on cross‐validation at the local scale of a 1‐ha plot over natural spruce–fir mixed forest in Jilin Province, China. Litter samples in semidecomposed (F) and complete decomposed (H) horizons were collected using an equidistant grid point sampling of 10 m × 10 m. Pearson correlation analysis and principal component analysis (PCA) were used to confirm auxiliary variables. The results showed that the amount of litter was 19.65 t/ha in the F horizon and 10.37 t/ha in the H horizon. The spatial structure variance ratio in the H horizon was smaller than that in the F horizon, indicative of its stronger spatial autocorrelation. Spatial distributions of litter amount in both horizons exhibited a patchy and heterogeneous pattern. Of the selected stand characteristics and litter properties, litter moisture content indicated the strongest relationship with litter amount. Cross‐validation revealed that COK_PCA using the comprehensive score as an auxiliary variable produced the most accurate map. The average standard error and root‐mean‐square error between the predicted and measured values were always smaller, the mean error and mean standardized error were much closer to 0, and the root‐mean‐square standardized error was closer to 1 than COK_P using litter moisture and OK. Therefore, a clear advantage of cokriging based on principal component analysis was observed and COK_PCA was found to be a very useful approach for further interpolation prediction.     

Comment on: "Energy landscape of a small peptide revealed by dihedral angle principal component analysis"

The dihedral angle principal component analysis method published recently by Mu, Nguyen, and Stock, is shown to produce distortions of the free energy landscape due to the neglect of constraints in the coordinates. It is further shown that these distortions can create artificial minima and energy barriers. The rugged energy landscape that the authors find for a small peptide chain might thus be an artifact of their method.     

Fungal successions on pine needles fallen at different seasons: The succession of interior colonizers

Experimental studies were carried out to investigate seasonal effects on the fungal succession in the interior or decaying pine needles. At different seasons, the needles fallen for a short period were collected and marked, then placed on the surface of the O horizon in a pine forest. The needles were removed at intervals and their interior fungal communities were examined by using a surface sterilization technique. The successions of interior colonizers observed on the fallen needles at four different times are roughly divided into three groups based on the composition of species colonizing from litter. Seasonal shifts in the species combination were discussed with climatic and biotic factors. As a result, temperature at the surface of litter appeared to be a cardinal factor contributing to these seasonal changes in the succession of interior colonizers. Contributions to Sugadaira Montane Research Center, No. 164.     

Carrion flies of forensic interest: a study of seasonal community composition and succession in Lisbon,Portugal

Information on Diptera community, seasonality and successional patterns in every geographical region is fundamental for the use of flies as forensic indicators of time of death. In order to obtain these data from the Lisbon area (Portugal), experiments were conducted during the four seasons of the year, using piglet carcasses as animal models. Five stages were recognized during the decomposition process. The stages, besides visually defined, could be separated taking into account the occurrence and abundance of the specific groups of Diptera collected. In general, the bloated stage recorded higher abundance and species‐richness values. Seventy‐one species were identified, belonging to 39 families, in a total of 20 144 adult Diptera collected. Autumn yielded the highest values of species richness, whereas winter had the lowest. In all seasons of the year, Calliphoridae was the dominant family; Muscidae and Fanniidae were very abundant as well. Calliphora vicina Robineau‐Desvoidy, Calliphora vomitoria (Linnaeus), Chrysomya albiceps (Wiedemann), Lucilia ampullacea Villeneuve, Lucilia caesar (Linnaeus), Lucilia sericata (Meigen) (Calliphoridae), Hydrotaea ignava (Harris), Muscina prolapsa (Harris), Synthesiomyia nudiseta (van der Wulp) (Muscidae), Piophila megastigmata McAlpine, Stearibia nigriceps (Meigen) (Piophilidae) and Nemopoda nitidula (Fallén) (Sepsidae) were revealed to be very important members of the Diptera community collected. The necrophagous behaviour, demonstrated by their immatures, using carrion as a food source makes them useful forensic indicator species. Also of relevance is the presence of Chrysomya megacephala (Fabricius), S. nudiseta and P. megastigmata, foreign species established in the local carrion communities. This study also marks the first record of S. nudiseta in Portugal.     

Fungal successions on pine needles fallen at different seasons: The succession of surface colonizers

Field experiments were carried out to investigate influences of seasonal change on the fungal succession occurring on the surface of decaying pine needles at a moder site in Japan. At different seasons, the needles fallen for a short period were collected and marked, then placed on the surface of the O horizon. The needles were removed at intervals and their fungal communities were examined by using a washing technique. Unlike the successions of interior colonizers studied at the same time, those of surface colonizers observed on the fallen needles at four different times are roughly similar to each other.Thysanophora penicillioides was the major first colonizer on the sample needles from the O horizon, andTrichoderma species followed it. In an experiment started in late autumn, three dematiaceous fungi,Chloridium viride var.chlamydosporis, Sporidesmium omahutaense, andChalara sp., commonly occurred and contributed to the darkening of colonized needles. Seasonal variation in climate may have a stronger effect on internal colonizers than external colonizers of needles. Contributions from Sugadaira Montane Research Center, No. 165.     

间作密植和单行茶园节肢动物群落组成差异

1998年1－12月每月下旬,对皖南敬亭山茶场栗－茶间作,梨－茶间作,3行密植和单行条植茶园节肢动物群落的调查表明：植食性昆虫种数分别占各类型茶园总物种数51．9％,53．6％,54．4％和56．6％,个体数依次占各类茶园总个体数92．0％,93．5％,93．6％和95．0％,捕食性昆虫和捕食螨种数则分别占11．3％,10．0％,9．8％,10．9％,个体数占2．0％,1．1％,2．0％和1．5％,寄生性昆虫种数占9．2％,9．1％,9．3％,和9．3％,个体数占1．8％,1．1％,1．8％和1．3％。蜘蛛种数占24．7％,20．1％,22．4％和19．4％,个体数占3．5％,3．4％,2．1％和1．8％,4类茶园中的优势类群都是鳞翅目,同翅目,翅目,双翅目和蜘蛛目,月平均丰富度（S）和多样性指数H大小,栗－茶间作（S＝74,H＝1．33）,梨－茶间作（S＝49,H’＝1．24）,3行密植（S＝31,H’＝1．03）和单行条植茶园（S＝23,H’＝0．89）,主成分分析揭示了群落稳定性的大小：栗－茶间作＞梨－茶间作＞3行密植＞单行条植茶园。     

The genus Poa in Patagonia (Argentine): a phenetic analysis of species of Poa subgenus Poa

Fifty-eight quantitative and qualitative exomorphological characters were recorded on 48 herbarium specimens belonging to rhizomatous species belonging to the genus Poa. These were treated as OTUs and analysed, together with the data from caespitose species treated in a previous paper, using cluster analysis, principal component analyses and stepwise discriminant analyses. The following hypotheses are proposed and discussed. (1) There is no evidence supporting the hypothesis that growth habit characterizes supraspecific entities. (2) P. trivialis, P. secunda, P. subenervis and probably P. compressa seem to be well defined species; those remaining are not discriminated through phenetic analysis. (3) There are no phenetic gaps between the rhizomatous species included in the P. oligeria—P. yaganica-P. chrysantha complex and the caespitose P. hachadoensis it is not clear that this single character supports its segregation. (4) The obscurity of the pattern of the species related to P. pratensis-P. nemoralis is probably explained by the capability of P. pratensis to introgress with taxonomically distant species and by the possibility of seasonal intraindividual variation of some characters. (5) The geographical origin of some species postulated as introduced seems to be doubtful.     

Data reduction prior to inference: Are there consequences of comparing groups using a t-test based on principal component scores?

Researchers often use a two-step process to analyze multivariate data. First, dimensionality is reduced using a technique such as principal component analysis, followed by a group comparison using a $t$-test or analysis of variance. Although this practice is often discouraged, the statistical properties of this procedure are not well understood, starting with the hypothesis being tested. We suggest that this approach might be considering two distinct hypotheses, one of which is a global test of no differences in the mean vectors, and the other being a focused test of a specific linear combination where the coefficients have been estimated from the data. We study the asymptotic properties of the two-sample $t$-statistic for these two scenarios, assuming a nonsparse setting. We show that the size of the global test agrees with the presumed level but that the test has poor power. In contrast, the size of the focused test can be arbitrarily distorted with certain mean and covariance structures. A simple method is provided to correct the size of the focused test. Data analyses and simulations are used to illustrate the results. Recommendations on the use of this two-step method and the related use of principal components for prediction are provided.     

Objective classification of scapular kinematics in participants with movement faults of the scapula on clinical assessment

The aim of this study was to assess the potential of employing a classification tool to objectively classify participants with clinically assessed movement faults (MFs) of the scapula. Six participants with a history of shoulder pain with MFs of the scapula and 12 healthy participants with no movement faults (NMFs) performed a flexion movement control test of the scapula, while scapular kinematic data were collected. Principal component scores and discrete kinematic variables were used as input into a classifier. Five out of the six participants with a history of pain were successfully classified as having scapular MFs with an accuracy of 72%. Variables related to the upward rotation of the scapula had the most influence on the classification. The results of the study demonstrate the potential of adopting a multivariate approach in objective classification of participants with altered scapular kinematics in pathological groups.     

Effects of a quantitative trait locus for increased muscularity on carcass traits measured by subjective conformation and fat class scores and video image analysis in crossbred lambs

A quantitative trait locus (QTL) for increased loin muscularity (TM-QTL) has previously been identified in purebred Texel sheep. Crossbred lambs born out of Mule ewes mated to heterozygous Texel sires for the TM-QTL were evaluated for a range of carcass traits. Lambs were genotyped and classified as carriers (n = 62) of a single copy of the TM-QTL and non-carriers (n = 49). In this study, the effects of the TM-QTL on carcass attributes were investigated using subjective classification scores for conformation and fatness, and measurements from a video image analysis (VIA) system. In addition, refined prediction equations to estimate weights of primal joints (leg, chump, loin, breast and shoulder) were obtained by calibrating the VIA system against computer tomography (CT) measurements in the loin region. The new refined prediction models increased the accuracy of prediction of all primal cuts on an average of 16% compared to previously derived standard VIA prediction equations. The coefficient of determination (R2) of the VIA system to predict in vivo CT measurements ranged from 0.39 to 0.72 for measurements of Musculus longissimus lumborum (MLL) area, width and depth, lumbar spine length, loin muscle volume and loin muscularity index. Using VIA estimates of CT-measured loin muscle traits, a significant increase in depth (+2.7%) of the MLL was found to be associated with the TM-QTL. Conformation and fatness scores and the shape of the carcass measured as individual lengths, widths and areas by VIA were not significantly influenced by the TM-QTL. Primal meat yields estimated using both standard and refined VIA prediction equations were not significantly affected by the TM-QTL. However, carcass 'compactness' was found to have significantly increased in carrier lambs. The weight of the dissected MLL estimated using VIA information was greater (+2.6%) for carriers compared to non-carriers. To conclude, neither the current industry carcass evaluation system for conformation and fatness nor the standard VIA system is able to identify the effect of the TM-QTL in the loin region in the moment. However, the calibration of the VIA system against CT measurements resulted in improved VIA prediction equations for primal meat yields and also showed moderate potential to estimate loin muscle traits measured by CT and to detect, partially, the effect of the TM-QTL on these traits.