七星瓢虫成虫对烟蚜的捕食作用

对七星瓢虫CoccinellaseptempunctataL .成虫对烟蚜Myzuspersicae的捕食作用进行了定量研究。七星瓢虫成虫对烟蚜的功能反应属HollingⅡ型反应 ,拟合的圆盘方程为Na =1 .1 5 76Nt ( 1 +0 .0 0 3 48Nt) ,χ2 检验表明圆盘方程理论值与实测值相符。捕食选择试验表明在烟蚜、烟青虫Helicoverpaassaut(Guenee)卵和 1龄幼虫 3种猎物中 ,七星瓢虫成虫最喜好烟蚜。七星瓢虫成虫对自身密度的功能反应用Watt模型拟合为A =2 90 .0 3P-0 .7584,其捕食作用率与个体间相互干扰作用的关系用Hassell模型拟合为E =0 .8783 7P-0 .1 0 0 94。文中进一步就烟田中七星瓢虫的保护利用进行了讨论。     

异色瓢虫对设施栽培桃树桃蚜的捕食功能反应研究

为明确异色瓢虫对设施栽培桃树上桃蚜的自然控制力,在室内研究了异色瓢虫成虫自身密度和不同蚜虫密度对捕食功能的影响。结果表明,异色瓢虫对桃蚜的捕食功能反应符合Holling-Ⅱ圆盘方程,其拟合模型为Na=0.898Nt/(1+0.0045Nt),每头异色瓢虫在1 d内对桃蚜的最大捕食量为200头,捕食每头桃蚜的处置时间Th=0.005d。异色瓢虫自身密度对桃蚜捕食作用有一定制约,拟合Watt竞争模型方程为A=86.441P-0.6592。     

双带盘瓢虫与六斑月瓢虫成虫对螺旋粉虱幼虫的捕食作用

在实验条件下分别研究了双带盘瓢虫Lemnia biplagiata与六斑月瓢虫Menochilus sexmaculatus Fabricius成虫对螺旋粉虱Aleurodicus dispersus Russell幼虫的捕食功能反应,并用Holling-Ⅱ型功能反应模型拟合.拟合的圆盘方程分别为Na=1.0776N/1+0.0032N和Na=0.8606/1+0.0060N,双带盘瓢虫和六斑月瓢虫的理论日最大捕食量分别为333.333头和142.857头.结果表明,两种瓢虫对入侵害虫螺旋粉虱有良好的捕食作用和控制潜能.     

两种瓢虫对刺槐蚜的捕食作用

在实验室条件下研究了龟纹瓢虫成虫和异色瓢虫成虫对不同密度刺槐蚜的捕食功能反应,符合HollingⅡ 型功能反应模型,其模型分别为:Na=0.4050/1+0.0073N和Na=0.4227N/1+0.0046N,x2值均小于X20. 05=9.49,最大捕食量分别为55.6头和90.9头.圆盘方程理论值与实测值相符.随着瓢虫密度的增加,单个瓢虫捕食率下降,龟纹瓢虫和异色瓢虫自身密度的干扰效应模型分别为:E=0.208P-0.235,E=0.236P-0.324.     

孪斑唇瓢虫成虫对桑白蚧的捕食功能

在实验室条件下,研究孪斑唇瓢虫Chilocorus geminus Zaslavskij成虫对桑白蚧Pseudau lacaspis pentagona(Targioni-Tozzetti)各虫态的捕食功能反应,寻找效应和干扰效应。结果表明,孪斑唇瓢虫成虫对桑白蚧各虫态的功能反应均符合Holling-Ⅱ型圆盘方程。孪斑唇瓢虫成虫对桑白蚧各虫态的寻找效应随自身密度的增加而降低。根据Holling-Ⅲ型功能反应新模型拟合出1头孪斑唇瓢虫成虫对桑白蚧各虫态的最佳寻找密度分别为:成虫26.7头、卵185.2粒、1龄若虫47.9头、2龄若虫46.8头。当孪斑唇瓢虫成虫与桑白蚧各虫态的数量同比例增加时,孪斑唇瓢虫成虫个体间的相互干扰系数为0.3901,0.7891和0.9827;当桑白蚧2龄若虫数量不变而孪斑唇瓢虫成虫数量增加时,孪斑唇瓢虫成虫个体间的相互干扰系数为0.0960。     

拟小食螨瓢虫捕食六点始叶螨的初步观察

在室内以六点始叶螨Eotetranychus sexmaculatus(Riley)为猎物观察了拟小食螨瓢虫Stethorusparapauperculus Pang的发育历期、捕食量、捕食作用及干扰效应。研究结果表明:拟小食螨瓢虫取食六点始叶螨时完成一个世代需23.2 d,幼虫1～4龄的捕食量分别为9.5、14.5、19.5、64.2头六点始叶螨成螨;成虫期对六点始叶螨成螨的捕食量高达880.4头,拟小食螨瓢虫对六点始叶螨的捕食作用符合HollingⅡ方程,拟合的模型方程为Na=1.3843 N/(1+0.0231N),日均最大捕食量为43.29头;拟小食螨瓢虫的捕食率与个体间的干扰效应用Hassell-Varley(1959)模型拟合为E=0.4690P-0.5470。     

深点食螨瓢虫和塔六点蓟马对朱砂叶螨的捕食作用

本文通过室内对深点食螨瓢虫Stethorus punctillum Weise和塔六点蓟马Scolothrips takahashii Priesener成虫捕食朱砂叶螨Tetranychus cinnabarinus(Boisduval)成螨的功能反应及种内干扰作用的研究,比较了2种天敌对朱砂叶螨的捕食能力。结果表明,深点食螨瓢虫和塔六点蓟马成虫对朱砂叶螨成螨的捕食功能反应均属HollingⅡ型,其模型分别为Na=0.7181N0/(1+0.0175N0)和Na=0.5168N0/(1+0.0136N0),日最大捕食量分别为41.11头和38.14头,处置时间分别为0.0243和0.0262d。深点食螨瓢虫和塔六点蓟马种内干扰模型分别为E=0.1916P-0.1805和E=0.1535P-0.4684。深点食螨瓢虫成虫对朱砂叶螨成螨的捕食能力强于塔六点蓟马。     

七星瓢虫成虫对绣线菊蚜捕食作用的室内测试

在实验室内测定了七星瓢虫成虫对苹果绣线菊蚜的捕食作用,结果表明,七星瓢虫成虫对绣线菊蚜密度的功能反应可用Holing-Ⅱ型圆盘方程较好地拟合,捕食作用在一定范围内随猎物密度的增加而加大;七星瓢虫成虫对绣线菊蚜的捕食作用率随着自身密度增加而减小,相互之间存在一定的干扰,自身密度的功能反应能用Hassell数学模型较好地反映。     

蠋敌对双斑长跗萤叶甲成虫的捕食功能研究

在室内研究了捕食性天敌蠋敌对双斑长跗萤叶甲成虫的捕食功能反应.结果表明,蠋敌对双斑长跗萤叶甲成虫的捕食功能符合HollingⅡ模型,日最大捕食量为20.4头双斑长跗萤叶甲成虫,捕食一头双斑长跗萤叶甲成虫需要2.94min,功能系数为0.5169;蠋敌成虫个体间相互干扰对捕食效应的影响可以用E=0.4046*P-0.3914模拟;蠋敌若虫对自身密度的功能反应可以用A=0.3034p-0.5357模拟.经卡方检验,其理论值与实测值无统计学差异.     

六斑月瓢虫对菊小长管蚜的捕食作用

六斑月瓢虫对菊小长管蚜的捕食功能反应符合HollingⅡ型方程。功能反应受到温度、容器大小和捕食者密度的影响。在同一温度下,六斑月瓢虫的捕食量随着猎物密度的增加而增大,寻找效应随着猎物密度的增加而降低。在15℃～25℃范围内,随着温度的升高,捕食的菊小长管蚜高龄若蚜头数增多,而在25℃～35℃有相反的趋势,以25℃下的捕食数量最大,平均达95头/天,捕食上限达392.1头。相同猎物密度条件下,温度与六斑月瓢虫捕食作用的关系可用二次曲线拟合,捕食的最适温度（25℃左右）与菊小长管蚜发生高峰季节的温度相吻合。六斑月瓢虫的捕食作用有较强的种内干扰反应,随着捕食者密度的增大,平均捕食量逐渐减少,捕食作用率也相应地降低,搜索常数Q为0.9003,干扰系数m为0.9816,E=0.9003P^-0.9816。实际应用时,要充分考虑气象因子、瓢蚜密度比等对防效的影响,以期获得最佳防治效果。     

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.