温度对前裂长管茧蜂生长发育与繁殖的影响

在实验室条件下,以桔小实蝇三龄初幼虫为繁育寄主,考察了15、18、21、24、27及30℃6个梯度恒温对前裂长管茧蜂生长发育与繁殖的影响.结果表明:在试验温度范围内,前裂长管茧蜂的世代发育历期随着温度的升高而缩短,发育历期由15℃时的45.7 d降至30℃时的15.2 d.温度过低或过高对前裂长管茧蜂的生长发育均有一定的抑制作用,15℃与30℃时寄生蜂的幼期存活率分别为10.2％和31.3％,而在24 ～ 27℃时,幼期存活率维持在50％左右.在试验设定的温度范围内,前裂长管茧蜂成蜂的寿命随着温度的升高而缩短,雌蜂的寿命稍高于雄蜂.前裂长管茧蜂的繁殖力以24℃时最高,能繁育74.2个后代,其次为27、21与18℃,分别能繁育53.4、35.7与31.6个后代,而在其他温度条件下,前裂长管茧蜂繁育的后代不超过20个.在15 ～24℃的范围内,种群中雌性比率随着温度的升高而增加,在24℃时最高为0.59;在21～27℃范围内,后代种群中以雌性个体为主.从综合反映昆虫种群生长发育与繁殖情况的指标内禀增长率来看,27 ℃时的内禀增长率最高,为0.1318;其次为24、21、30与l8℃,相应的内禀增长率分别为0.1239、0.0747、0.0318和0.0187.而15℃时的内禀增长率与种群趋势指数分别为-0.0240和0.8,种群数量呈负增长趋势.24 ～27℃是前裂长管茧蜂生长发育与繁殖的适宜温区.     

几种因子对马尼拉侧沟茧蜂寄生效能的影响

马尼拉侧沟茧蜂Microplitis manilae是斜纹夜蛾Spodoptera litura的一种重要幼虫寄生蜂。本文以斜纹夜蛾2龄幼虫为寄主,在26±1℃、RH 65%±5%、L：D=12:12的人工气候箱内,研究生殖方式、雌蜂日龄、寄生时间段、雄蜂出现与否以及雄蜂密度等因子对其寄生效能的影响。结果表明：马尼拉侧沟茧蜂可营产雄孤雌生殖和两性生殖两种生殖方式,两种方式在亲代寄生率、子代羽化率和发育历期均无显著差异。随着雌蜂日龄的增加,其寄生率和子代性比显著降低,但子代发育历期随雌蜂日龄的增加而延长。马尼拉侧沟茧蜂在12:00-18:00时间段的寄生率、子代羽化率和性比最高,子代发育历期最短。当寄生蜂密度一定时,子代性比随着寄主密度的增加而显著增加;当寄主密度一定时,子代性比随着寄生蜂密度的增加而显著下降;雄蜂在场时,子代性比显著高于无雄蜂在场时。子代性比随着亲代雄蜂密度的增加而显著降低,但雄蜂密度对亲代寄生率,子代羽化率、发育历期无显著影响。     

滞育烟蚜茧蜂的亲代效应评价

【目的】烟蚜茧蜂Aphidius gifuensis Ashmead是可持续防控蚜虫的优良内寄生蜂,适宜的低温短光照可诱导其进入滞育,滞育后产品货架期长达120 d,对害虫生防意义重大。为深入探索滞育烟蚜茧蜂的亲代效应,分析滞育机理,提高滞育诱导效率,指导该天敌产品的贮存实践,开展本项研究。【方法】在室内测试了滞育烟蚜茧蜂F1代的羽化率、性比、成蜂寿命、滞育率、寄生力以及F2代的羽化率、性比等生物学指标,综合评价滞育烟蚜茧蜂的亲代效应。【结果】滞育经历对烟蚜茧蜂子代的部分生物学性状具有显著性影响,F1代雌蜂比例显著增加,滞育维持30 d后子代雌蜂比例由0.59上升至0.65;F2代雌蜂比例与CK无差别,维持在0.58左右;F1代滞育率显著升高,可由对照的44.75%提高至74.01%,滞育维持30 d后子代滞育率具升高趋势;F1代寄生力略增加,各处理形成的僵蚜数在117~129头间,但无显著性差异;F1代羽化率、子代成蜂寿命与CK相比无差异。【结论】烟蚜茧蜂具有较显著的滞育亲代效应,亲代滞育经历可显著提高子一代的滞育率,利于子代抵御不良环境胁迫,提高种群存活率。     

短时高温胁迫对斑痣悬茧蜂发育指标的影响

全球气候变化不仅包括平均气温上升,而且诸如热浪的极端天气事件出现的频率和程度也增大。寄生蜂虽在寄主体内完成生长发育,也会受到极端气温的影响。为探究短时高温对寄生性天敌斑痣悬茧蜂(Meteorus pulchricornis)幼虫发育表现的影响,以斜纹夜蛾(Spodoptera litura)幼虫为寄主,分别对1—6日龄子代蜂进行39℃、持续4h的高温胁迫处理,以发育全程进行适温(昼29℃、夜26℃)处理为对照,观察子代存活、发育历期、羽化和成虫寿命等发育指标。高温胁迫处理1日和5日龄子代蜂幼虫使幼虫存活率下降,与对照相比分别降低36.1%和28.6%;高温胁迫可延长子代蜂幼虫发育历期,与对照相比,高温处理2、3、5日和6日龄子代蜂幼虫使幼虫发育历期分别延长了5.0%,5.2%,7.0%和12.1%;高温胁迫处理5、6日龄子代蜂幼虫使羽化出的成虫体型(用后足胫节长度表示)比对照分别减小1.8%和2.6%。高温胁迫处理对子代蜂蛹发育历期、羽化率以及成虫寿命等均没有显著影响。研究结果说明,短时高温胁迫对斑痣悬茧蜂高龄幼虫的负面影响比对低龄幼虫大。     

转Bt基因水稻对二化螟绒茧蜂生物学特性的影响

用转Bt基因 (cry1Ab) 水稻KMD1饲喂3龄、4龄和5龄二化螟Chilo suppressalis一定时间后, 作为二化螟绒茧蜂Apanteles chilonis的寄主,研究了转基因水稻经寄主对绒茧蜂生物学特性的影响。结果发现：KMD1处理后,三个龄期幼虫的寄生率都显著下降,其中4龄和5龄达极显著水平;3龄和4龄上的结茧率显著低于对照;蜂蛹历期均短于对照,但仅3龄差异显著;从5龄幼虫所羽化的雄蜂寿命显著短于对照;蜂茧长显著短于对照;而对卵＋幼虫期、茧块茧数、蜂羽化率及性比均无显著影响。     

低温贮存对椰心叶甲啮小蜂品质的影响

研究低温贮存椰心叶甲蛹Brontispa longissima(Gestro)和椰心叶甲僵蛹对椰心叶甲啮小蜂Tetrastichus brontispae Ferriere种群品质的影响。寄生10℃低温贮存1~4日龄椰心叶甲蛹结果表明,1日龄椰心叶甲蛹的寄生率、羽化率、出蜂率、单蛹出蜂数、后代寄生能力均优于其他日龄,其次为2、3日龄的椰心叶甲蛹,最差为4日龄的椰心叶甲蛹。1日龄椰心叶甲蛹在10℃下贮存5,10,15,20d后,上述生物学指标和种群参数均随贮存天数增加而降低,其中以5d和10d的净生殖率、内禀增长率和周限增长率较未经低温贮存的差异小。1~11日龄椰心叶甲僵蛹于10℃贮存10d的结果表明,8日龄椰心叶甲僵蛹的雌蜂寿命、羽化率、单蛹出蜂数、寄生能力均优于其他日龄僵蛹。8日龄椰心叶甲僵蛹在10℃下贮存5,10,15,20d后,上述生物学指标和种群参数均随贮存天数增加而显著低于对照。     

前裂长管茧蜂个体发育研究

前裂长管茧蜂Diachasmimorpha longicaudata（Ashmead）是许多双翅目实蝇类害虫的重要寄生性天敌。在实验室条件下,以桔小实蝇Bactrocera dorsalis（Hendel）为繁育寄主,系统观测了前裂长管茧蜂个体发育过程中各虫态的特征及其相应的发育历期。观察结果表明,前裂长管茧蜂整个生活史由卵、幼虫、蛹及成虫四个阶段组成。其幼虫可划分为四个龄期,一龄幼虫具几质丁的坚硬头壳和镰刀状的颚,形态特征与行为习性与二、三、四龄幼虫完全不同。前裂长管茧蜂约需20天完成世代发育。卵、一龄幼虫、二龄幼虫、三龄幼虫及四龄幼虫的历期依次为1．91、2．02、1．75、2．04和2．31d;蛹的历期介于8～10d,雌性个体发育时间长于雄性。前裂长管茧蜂通常比未被寄生的寄主迟3～5d羽化,雌、雄蜂在羽化后即能交配、产卵,被寄生的桔小实蝇幼虫体表上会留下明显的深褐色产卵孔,寄主化蛹后产卵孔仍保留在其蛹壳上。     

阿维菌素对广赤眼蜂（Trichogramma evanescens）不同发育阶段的毒性和实验种群动态的影响

研究了阿维菌素对广赤眼蜂不同发育阶段的毒性和实验种群动态的影响.结果表明,阿维菌素田间推荐剂量喷雾处理可显著降低米蛾卵内广赤眼蜂的羽化率;除卵期外,其它3种发育阶段经该药处理,羽化后的雌蜂寿命显著缩短,其中预蛹和蛹期处理雌蜂前翅畸形率高达43.3%～47.2%,影响程度随着其生长发育的进行呈增大趋势.根据药膜法剂量与效应测定结果,广赤眼蜂成蜂对阿维菌素比较敏感,LC50值为2.1991mg·L-1.温室盆栽试验表明,1.8%阿维菌素乳油对广赤眼蜂成蜂的持效期为10d,具有一定程度的残留毒性.广赤眼蜂的蛹经阿维菌素亚致死剂量LC35处理后,发育至成蜂,除羽化后的雌蜂产卵量显著减少外,雌蜂寿命、子代羽化率和子代性比与对照并无显著差异.生命表参数显示,LC35处理后的广赤眼蜂净增值率和世代平均历期明显地低于对照,但内禀增长率、周限增长率和种群倍增时间与对照差异不明显.可以认为阿维菌素亚致死剂量对广赤眼蜂的种群没有重要影响.     

日木食蚧蚜小蜂低温贮藏条件研究

日本食蚧蚜小蜂Coccophagus japonicus Compere为橡副珠蜡蚧Parasaissetia nigra Nietner的优势天敌之一。为了探明该蜂的贮藏条件,本研究将1日龄、3日龄的日本食蚧蚜小蜂蛹在10℃、12℃、14℃条件下分别贮藏7、9、11、13、15、17、19、21、23、25、27 d,观察其羽化率及羽化后的成蜂寿命、产卵量、寄生率等。结果表明:日本食蚧蚜小蜂的羽化率随贮藏温度的升高呈上升趋势;同一温度贮藏相同时间后3日龄蛹羽化率均高于1日龄蛹。贮藏时间是日本食蚧蚜小蜂蛹存活的重要影响因子,3日龄蛹10℃贮藏7 d,羽化率为96.00%,贮藏27 d,羽化率仅为44.67%;12℃贮藏7 d,羽化率为96.67%,27 d蛹羽化率达88.00%;在14℃贮藏25 d后在人工气候箱内有小蜂羽化。低温贮藏蛹羽化后的成虫寿命随贮藏温度的降低而缩短;14℃贮藏后,羽化成蜂寿命随贮藏时间增加而显著缩短,10℃、12℃降低不明显;10℃贮藏23 d后寿命仅为10.11 d。3日龄蛹12℃贮藏19、21、23、25、27 d后羽化成蜂产卵量及寄生率均随贮藏时间的增加而降低,在贮藏27 d时最低,分别为34.33%、51.67%。综上所述,在12℃条件下短期贮藏日本食蚧蚜小蜂3日龄蛹27 d以内对其存活影响不大,12℃、3日龄蛹可作为该蜂的贮藏条件。     

斑痣悬茧蜂对斜纹夜蛾不同虫龄幼虫的选择及后代发育表现

为探究容性寄生蜂对不同龄期寄主幼虫的选择性及其子代蜂发育表现的关联,通过双选试验观察了斑痣悬茧蜂(Meteorus pulchricornis)对斜纹夜蛾(Spodoptera litura)不同虫龄幼虫的寄生选择,并观察了与子代蜂适合度相关的特性表现.结果表明:斑痣悬茧蜂在4龄与5龄之间未表现出偏好,在2龄和3龄、3龄和4龄之间显著偏好较低虫龄;结茧率在不同寄主虫龄间无显著差异,羽化率随寄主虫龄增大而减小,寄生2、3龄幼虫的子代蜂显著高于寄生5龄;寄生5龄幼虫的子代蜂死亡率比寄生2龄的高2.5倍,比寄生3龄的高5.4倍.寄生3龄幼虫的子代蜂发育历期最短(11.9 d),比寄生4龄幼虫的短6.8 d,比寄生2龄幼虫的短4.7 d;子代蜂体型大小在寄生的寄主虫龄间无显著差异.根据研究结果推测,斑痣悬茧蜂在寄生时可能不是根据寄主龄期来评价寄主品质,而是基于寄主体型大小进行评价.     

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.