避难所对七星瓢虫捕食桃蚜功能反应的影响

自然情况下的捕食是以植物为中介发生的。作者采用植物模型作为捕食环境,测试了单纯的物理因素(避难所)对七星瓢虫Coccinella septempunctata L.捕食桃蚜Myzus persicae(Sulzer)的功能反应的影响。结果表明,避难所的存在能造成七星瓢虫捕食量和捕食率极显著下降,对雄虫的影响显著比雌虫强,且在中等猎物密度时影响更为突出。Logistic回归分析发现,七星瓢虫雌虫和雄虫无论避难所是否存在,功能反应类型均为HollingⅡ型。避难所不存在的情况下,雌、雄成虫的圆盘方程分别为N a=1.0259 N0/(1+0.003078 N0)和N a=0.9246 N0/(1+0.002127 N0),避难所存在的情况下,其圆盘方程分别为N a=0.9500 N0/(1+0.00342 N0)和N a=0.6463N0/(1+0.002262 N0)。避难所的存在能导致两性成虫瞬时攻击率极显著下降,但仅雄虫处置时间极显著延长,说明雄虫在环境异质性较高时捕获猎物更困难。     

白蜡虫产卵期雌虫密度与黑缘红瓢虫发育历期和捕食作用的关系

本文研究了白蜡虫Ericerus pela Chavannes产卵期雌虫密度对黑缘红瓢虫Chilocorusrubidus Hope发育历期的影响.结果表明,黑缘红瓢虫1-4龄幼虫发育历期与白蜡虫产卵期雌虫密度呈幂函数关系:Y=aX-b,相关系数达极显著.经回归系数显著性检验,对白蜡虫被捕食率造成显著影响的因子主要有白蜡虫密度(X1)、黑缘红瓢虫3、4龄幼虫和成虫密度(X4、X5、X6).白蜡虫产卵期雌虫、黑缘红瓢虫各龄幼虫和成虫自身的交互作用均达显著水平,但这些因子之间的交互作用均未达显著水平.剔除不显著因子后的优化模型为:Y=0.7438-0.0625X1+0.0517X4+0.0708X5+0.0483X6-0.0817X12-0.0392X22-0.0257X32-0.0392X42-0.0392X52-0.0392X62.     

蚂蚁光顾云南紫胶虫对其天敌紫胶黑虫种群的影响

为了弄清蚂蚁光顾云南紫胶虫Kerria yunnanensis Ouet Hong对其天敌紫胶黑虫Holcocera pulverea Meyr种群的影响,于云南紫胶虫成虫期,对有无蚂蚁光顾的胶被抽样,调查胶被上紫胶黑虫的为害率及种群数量变化。结果显示,紫胶黑虫对有无蚂蚁光顾的胶被的为害率均很高,并逐月增加;其中有蚂蚁光顾的胶被紫胶黑虫的为害率略小于无蚂蚁光顾的胶被。蚂蚁光顾能明显减少紫胶黑虫的种群数量(︱t︱=2.764,df=356,P<0.01),其原因可能是蚂蚁光顾能干扰紫胶黑虫的产卵行为、破坏卵、取食卵和幼虫并且这种保护主要发生在云南紫胶虫幼虫期;云南紫胶虫进入成虫期后,由于紫胶黑虫生活于胶被内,并且产卵于胶被的凹陷处或雄虫胶壳内或雌虫肛突孔处,蚂蚁很少与紫胶黑虫相遇,故蚂蚁光顾对紫胶黑虫每月增长量没有显著影响(︱t︱=0.970,df=161,P>0.05)。紫胶黑虫和蚂蚁相遇的行为反应存在显著差异(χ2=4.781,df=1,P<0.05),蚂蚁对紫胶黑虫有捕食作用。蚂蚁与云南紫胶虫之间存在互利关系。蚂蚁取食云南紫胶虫的蜜露,能降低紫胶黑虫的为害率,并减少紫胶黑虫的种群数量,从而保护云南紫胶虫。     

龟纹瓢虫对豆蚜的捕食功能反应及寻找效应研究

龟纹瓢虫雌虫和雄虫对豆蚜的功能反应符台Holling Ⅱ型模型,其模型为：Na=0．9233N／(1 0．0171N)(雌虫)和Na=0．8641N／(1 0．0164N)(雄虫),瓢虫捕食豆蚜的数量随豆蚜密度增加而增加．但寻找效应随豆蚜密度增加而降低。日最大捕食量和最佳寻找密度分别为37.42(雌)、34．11头(雄)和17．25（雌)、15．8头(雄)。龟纹瓢虫寻找效应随自身密度的增加而降低,其数学模型为：E=0．3032·P^-15634(雌)和E=0．3048·P^-1.1697(雄)。干扰反应的教学模型为：E=0．8104·P^-2.1721(雌),E=0．7125·P^-2.2660,E=0．5963·P^-2.1751(雌雄混台种群)。     

杧果切叶象成虫密度对繁殖的干扰效应

杧果切叶象成虫密度对雌虫产卵习性影响不大。成虫密度与雌虫单日平均产卵量呈直线负相关,与单叶平均着卵量呈曲线正相关。按幼虫取食最计算得出成虫最大允许密度,泰国杧、印度901和缅甸杧分别为2.0、2.9、4.2(对/梢)。     

蝇蛹金小蜂对桔小实蝇蛹的寄生功能反应

在温度25±1℃、相对湿度70±5%、光照周期（L∶D）14 h∶10 h条件下,研究了蝇蛹金小蜂对桔小实蝇蛹的寄生功能反应及干扰效应。结果表明,寄主密度、寄主日龄均影响寄生蜂的寄生效能。蝇蛹金小蜂对桔小实蝇2日龄（N=2）、4日龄（N=4）蛹的寄生功能反应均符合HollingⅡ模型,其方程分别为Na= 0.4494N2/ (1+ 0.0294N2)、Na= 0.5586N4/ (1+ 0.0253N4)。24h内单头雌成蜂最多可寄生2日龄、4日龄蝇蛹数量分别为15.29、22.08头。自身密度对蝇蛹金小蜂寄生产生一定的干扰效应,其干扰效应符合Hassell－Varley模型（a= 0.0719P－0.2526）,表明蝇蛹金小蜂雌蜂的发现域随着自身密度的增加而逐渐变小,雌蜂个体间干扰效应降低了寄生效能。     

粉虱小毛瓢虫Nephaspis oculatus(鞘翅目,瓢虫科)捕食功能反应与寄主植物选择(英文)

Nephaspisoculatus (Blatchley)属毛瓢虫亚科的小毛瓢虫族 ,专食粉虱。它源于中美洲 ,自七十年代初就在美国佛州被发现 ,是柑橘和蔬菜上白粉虱的重要天敌。本研究确定了该瓢虫各幼虫龄期和雌雄成虫在青菜 (col lard)叶上捕食银叶白粉虱BemisiaargentifoliiBellows&Perring卵在 6个密度的捕食功能反应及其成虫对 5种寄主植物的选择。结果表明 ,该瓢虫捕食率与白粉虱卵的密度呈线性相关。除第四龄幼虫其相关系数 (r2 )仅为0 .6 33外 ,其它各虫态的相关系数高达 0 .82 7～ 0 .94 4。根据该瓢虫各龄幼虫和雌雄成虫捕食量和白粉虱卵密度的关系 ,其捕食功能反应符合Holling圆盘方程的第二种反应模式。随着龄期的增加 ,幼虫捕食白粉虱卵的量也随之增加。第四龄幼虫捕食白粉虱卵量最多可达 312粒 ,其次为第三龄幼虫 2 2 9粒 ,第二龄幼虫 73粒 ,而第一龄幼虫捕食量仅为 34粒。雌成虫捕食白粉虱卵量 (32 1粒 )明显高于雄成虫 (2 37粒 )。雌成虫特别喜欢在青菜上活动、取食和产卵 ,而不喜欢番茄 ,大豆 ,茄子和甘薯。有 4 4 .9%的雌成虫在青菜上活动 ,只有 9.9% - 17.1%的雌成虫在其它植物上活动。雌成虫在青菜 ,甘薯和茄子上的产卵量占总产卵量的比率依次为 95 .8% ,2 .8%和 1.4 % ,而无任何卵产在番茄和大豆上。     

牧草盲蝽空间分布型及其应用技术研究

牧草盲蝽一代成虫在棉田呈聚集分布,其聚集原因是由环境作用所致。当t=1.64 D=0.2时,其最适抽样数为:N=92.7441/x+46.8797。若防治指标为0.1头/株,则最大抽样数为975株,防治的上下限为:T_9(N)=0.1N±0.7461N~(1/2)。田间调查时,可用有虫株率对平均密度进行简易估计,其公式为: x=1.4219[-ln(1-p)]~(1.0646)。     

黑松人工林生物量结构的数学模型

本文对蚌埠市郊黑松人工林生物量和生产力进行了系统测定和分析。林分的总生物量为64.604_t·ha~(-1)．地上部分为49.69_a·ha~(-1),占总生物量的76.9％;地下根系仅为14.914_t·ha~(-1)。并建立了估测黑松人工林各器官生物量的数学模型;W_T=0.1279D~(2.3599)、W_A=0.0462（D~2H）~(0.9446)、W_S=0.00957D~(2.2926)、W_(BR)=0.006（D~2H）~(1.2958)、W_L＝O.0276D~(1.7541)、W_(BK)＝0.0135（D~2H）~(0.873)、W_R＝0.0196D~(3.5023)、W_T＝-6.410＋11.950W_L。黑松人工林平均单株年净生长量为1.532kg·ha~(-1)·a~(-1),仅为同地区马尾松人工林生长量3.01kg·ha~(-1)·a~(-1)的一半。引起黑松人工林生长量低和生物量少的主要原因是黑松人工林针叶量少,生态环境不适宜黑松人工林生长。目前应对低产黑松林进行改造,无力改造的地区要保持林分较大密度,以提高林分的总生长量。     

闪蓝红点唇瓢虫对考氏白盾蚧的捕食作用研究

闪蓝红点唇瓢虫是猕猴桃考氏白盾蚧的主要天敌,在湖南一年发生1代,以幼虫在猕猴桃树干及枝条上的考氏白盾蚧下或以蛹在立架铁丝和猕猴桃小枝上越冬,该瓢虫成虫对考氏白盾蚧卵的功能反应属于Hassell &Comins Ⅲ型,对雌成蚧和雄蛹的功能反应属于Holling Ⅱ型;取食卵的“S”型曲线方程为Na=0.06339N/1+0.06339N+7.16307×10~(-5)·N~2,取食雌成蚧和雄蛹的圆盘方程分别为Na=1.0211N/1+0.008443N和Na=0.7315N/1+0.002394N;一昼夜对卵、雌成蚧、雄蛹的最大捕获量分别为885粒、121头和308头。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.