杆状病毒生态学研究进展

杆状病毒是一类寄生于鳞翅目、膜翅目和双翅目昆虫及其它节肢动物的病原体,是具有囊膜的双链环状DNA病毒.目前至少已从600多种昆虫中发现有杆状病毒的感染,其中一部分能够引起宿主种群不同程度的流行病.杆状病毒在分类上独立为杆状病毒科,其典型的结构特征是病毒粒子包埋于蛋白质基质的包涵体中.     

昆虫种群动态模拟模型

昆虫是动物界中最大的类群,与人类有着密切的利害关系。对昆虫的数量预测与符合经济和生态规律的管理,一直都被国内外列入重点研究课题。种群动态模拟是害虫管理中重要的基础工作。近十年来,关于昆虫种群动态模型的理论和实验研究进展迅速。现分别从单种种群和多种种群两个方面对国内外近些年来昆虫种群动态模拟模型的研究进展进行了概括和总结。单种种群从两个方面阐述:一是最基本的种群动态模拟模型Log istic方程的研究成果,包括方程的修正、参数的拟合与最优捕获策略等;另一个方面是对种群动态模拟常用的矩阵模型的概述,主要介绍不等期年龄组、矩阵维数的变化、矩阵维数与历期的关系、个体之间的发育差异以及发育速率差异等等对昆虫种群动态模型的影响。多种群主要从建模和模型应用两个部分对国内外研究成果进行综述。最后,对种群动态模拟模型研究的发展方向做了深入地讨论,即在原有的数据采集工作的基础上,使用面向对象程序设计语言,把各种要素包括各种物种及各种环境条件抽象成类,用消息传递来表示昆虫种群内个体与个体、昆虫种群与环境之间的相互作用,再结合先进的数学算法,建立一个直观的、操作简单的昆虫种群动态模型库,使模型结构与现实世界有最大的相似性。这样就可以实现昆虫种群动态的可视化、立体化、实时化和精确化的监测及预测。     

杆状病毒在昆虫中的持续感染

杆状病毒（Baculovirus）是一类特异性感染节肢动物的环状双链DNA病毒,是野外控制害虫种群的重要生物因子,并已被开发为一种生物杀虫剂加以应用。杆状病毒感染昆虫宿主并不一定导致昆虫死亡,其持续感染（persistentinfection）在昆虫种群中普遍存在,且在某些刺激条件下,持续感染可被激活为增殖性感染并引发病毒流行病爆发。因此,杆状病毒持续感染对昆虫种群动力学以及病毒流行病学的研究具有重要意义。     

一类大尺度系统中昆虫种群时空动态模拟方法

本文介绍了一类描述大尺度作物系统害虫种群时空动态的模型,该模型包含了寄主作物,昆虫密度以及天敌间的相互作用,并简要介绍了该模型的一些模拟结果在IPM中的应用。     

昆虫杆状病毒若干基因的研究进展

昆虫杆状病毒(Insect baculovirus)对鳞翅目、双翅目和膜翅目等昆虫具有病原性,是一 种开发应用较广、高效的生物杀虫剂,具有杀虫专一、效果好、有流行传播作用等优点.为 了更好地利用昆虫杆状病毒为防治农林害虫服务,加快昆虫杆状病毒杀虫剂研究的步伐,本文归纳了近几年来有关昆虫杆状病毒基因研究进展供从事研究的人员参考.     

昆虫种群动态模拟方法的一点改进──三化螟种群动态模拟模型的研究

以Ｒｕｅｓｉｎｋ（１９７６）的模型为基础,根据昆虫个体一般不同步地进入下一发育阶段的状况,当昆虫各虫态发育到完成该虫态发育所需要的最低年龄级数后,假定各年龄级的昆虫种群均以一定的概率分布函数值进入下一个发育阶段,同时根据有效积温向前推进。据此,对昆虫种群动态模拟方法作了一点改进。该方法综合了已有的种群模型的优点,因而较Ｒｕｅｓｉｎｋ（１９７６）和ＣｈｉＨｓｉｎ等（１９８５）提出的方法更真实地反映了昆虫种群动态的变化规律。根据三化螟自然种群生命表的资料,分析和确定逐日存活率、逐日发育率和逐日生殖率,对三化螟种群进行逐日动态模拟和预测,同时引入环境因素对种群的控制作用,研究不同环境条件下的种群动态,经验证,模型基本能够反映田间三化螟的发生规律。     

异质种群动态模型:破碎化景观动态模拟的新途径

景观破碎化导致物种以异质种群方式存活,使得基于异质种群动态模拟破碎化景观动态成为可能。异质种群动态模型的发展为景观动态模拟奠定了良好基础。根据空间处理方式的不同,异质种群模型可分为三大类,可不同程度地用于描述破碎化景观动态。(1)空间不确定异质种群模型,假定所有局域种群间均等互联,模型中不包含空间信息,仅能用于景观斑块动态描述;(2)空间确定异质种群模型,假设局域种群在二维空间上以规则格子形式排列,是一种准现实的空间处理方式,可用于景观动态的简单描述;(3)空间现实异质种群模型,包含了破碎化景观中局域种群的几何特征,可直接用于真实景观动态的模拟研究。空间现实的和基于个体的异质种群模型不但是未来异质种群模型发展的主流,也将成为未来破碎化景观动态研究的重要工具。为了更加准确完整地描述破碎化景观动态,不但应该综合运用已有的各种异质种群模型方法,更要引进新模型来刎画多物种、多变量、高维度、复杂连接的破碎化景观格局与过程。     

16型人乳头瘤病毒衣壳蛋白在真核细胞中的表达

为了构建HPV16型晚期蛋白重组杆状病毒,并使其在昆虫细胞中获得高效表达.首先构建2株重组杆状病毒转移质粒,分别携带人乳头瘤病毒晚期基因L1及L1和L2,再用线性化的杆状病毒DNA与该重组杆状病毒转移质粒共转染sf9昆虫细胞进行同源重组,获得2株重组杆状病毒.经鉴定该重组病毒中有目的基因存在且可表达所编码的L1或L2晚期蛋白.结果表明HPV16型晚期蛋白在昆虫细胞中获得成功表达,为HPV16型预防性基因工程亚单位疫苗的研制和诊断试剂的研究开发奠定了基础.     

基于智能体模型的土地利用动态模拟研究进展

土地利用动态变化是全球变化和可持续发展研究的基础,对区域水循环、大气循环、环境质量、气候变化及陆地生态系统生产力等具有重要影响,也是造成生物多样性衰减的最主要原因.目前,建立于复杂性科学基础上的的智能体模型(ABM)成为土地利用动态模拟的重要方法.智能体模型能模拟个体或群体的行为及决策模式,从而能将政府、城市规划、房地产开发商、住户等社会群体及个人对土地利用产生的影响进行模拟,同时能对不同社会经济政策对土地动态影响进行模拟.智能体模型在元胞自动机基础上,加入了人为因素的智能体概念,从而能更好地模拟土地动态.在分析总结了智能体模型的相关概念和组织结构,并分析了其在土地利用动态、城市动态模拟及生态过程模拟等方面的应用与元胞自动机的关系,比较了常用的智能体模型的主要软件,最后概括了智能体模型优点、发展趋势及存在的主要问题.     

昆虫杆状病毒表达系统的研究进展与应用

昆虫杆状病毒表达载体系统具有安全性好、重组蛋白表达量高、能同时表达多个基因、重组蛋白翻译后加工完整等特点,因而得到了广泛的应用。随着重组杆状病毒构建技术的不断发展,昆虫杆状病毒表达载体系统的操作在逐渐简化,重组杆状病毒获得的效率也在不断提高。昆虫细胞培养技术的改进和转基因昆虫细胞系的发展,进一步推动了昆虫杆状病毒表达载体系统在商品化药物、治疗性抗体、生物农药研发和基因治疗中的应用。尽管仍存在着重组蛋白降解的问题,但随着分子生物学技术的发展,对杆状病毒载体的研究与改造也会更加深入,未来昆虫杆状病毒表达载体系统的应用将更为广泛。     

Biological pest control by investing crops in pests

We propose a biological pest control system that invests part of a crop in feeding a pest in a cage. The fed pest maintains a predator that attacks the pest in the target area (i.e., the area for storing or growing crops). The fed pest cannot leave the cage nor the target pest cannot enter the cage. The predator, however, can freely attack both the fed and target pests in the target area. By introducing a refuge in the cage against the predator for the fed pest, the fed pest and predator may be stably sustained. In this study, we analyzed the potential performance of this system by modeling the population dynamics of the target pest, fed pest, and predator as differential equations. First, we show analytically that the target pest can be suppressed at extremely low abundance by adjusting both refuge efficiency and crop investment. Second, we show numerically that crop damage by the pest may be effectively suppressed by investing only small amounts of the crop. Third, we show numerically that the magnitude of required crop investment can be estimated by an index comprising of the predator's searching cost for prey and the relative growth efficiency of the predator with respect to the pest. Even if the system structure is changed or its population dynamics is modeled based on host–parasitoid interactions, crop damage can be suppressed effectively by small amounts of crop investment.     

稻纵卷叶螟(Cnaphalocrocis medinalis Guene''e)种群生命系统模型的研究

经过五年来对稻纵卷叶螟自然种群生命表的研究,组建了预测种群动态的生命系统模拟模型。本模型为一变维矩阵组合模型。除能随环境温度而改变矩阵维数外,采用生理年龄为矩阵步长。每一虫期内各个体的发育不一致,矩阵中各元素均为某些环境因素的函数,共组建有18个子模式。在输入起始日期,预测期限,水稻生育期,环境温、湿度和初始种群各年龄向量后,即可自动打印出逐日种群年龄向量及总虫量。计算机模拟曲线与实测曲线基本吻合。本模型可用来预测南京地区稻纵卷叶螟二代迁入峰后种群的发展以至第三代种群各虫态的起始虫量和发生期。     

Evaluation of pest control efficiencies for different banker plant systems with a simple predator–prey model

The banker plant system has been introduced for the biological control of various pest species in Japanese greenhouses. With the banker plant system, non-crop plants infested with a host insect (a non-commercial crop pest) are placed in the greenhouse to provide alternative resources for the parasitoids or predators. We want to evaluate the effectiveness for controlling pests on the crop in a quantitative way by immigrating predators from the banker plant. Therefore, we developed a simple model for the interaction of the pest and predator in the crop and included the banker plant only as a source for predators. For three different pest-predator systems we parameterised the model and used these models to predict under what conditions biological control in a banker plant system is successful. We defined successful as keeping the pest below the economic injury level of the crop estimated from damage analysis. Because the crop is mostly grown during a period that lasts less than a year our analysis should not only focus on the equilibrium dynamics. In contrast, it should also focus on the transient dynamics. Our main analytical result, from the equilibrium analysis, is that for successful control the maximum lifetime consumption of immigrating predators should exceed the daily prey growth at half the value of the maximum consumption rate. For practical purpose this translates into the fact that the immigration of predators at a low initial pest density is crucial for successful control.     

21世纪害虫管理的一些特征展望

分析了近年来国内外IPM研究的进展 ,认为未来的害虫管理是以作物的控害作用为中心 ,以农田生态系统或区域性生态系统为对象 ,以大量信息管理为基础 ,以发展新技术 (转基因作物和昆虫性信息素 )和农民参与为重点 ,以生态调控为手段 ,以持续发展为方向。从而使害虫管理提高到一个新的境界     

Beyond Bt resistance of pests in the context of population dynamical complexity

Complexity in ecological systems often prevents long-term predictions about changes in population size and properties of the population dynamics. Mathematical modeling of such complex system behaviors can provide a rough idea of scenarios of the population dynamics. We use the reaction–diffusion model [Medvinsky, A.B., Morozov, A.Y., Velkov, V.V., Li, B.-L., Sokolov, M.S., Malchow, H., 2004. Modeling the invasion of recessive Bt-resistant insects: an impact on transgenic plants. J. Theor. Biol. 231, 121–127] to study the impact of pests resistant to toxins produced by genetically modified plants on the dynamics of the plant–insect system. Using genetically modified crops is an effective pest management tool for world-wide growers. However, there is a concern that pests may develop resistance to Bt toxins, which are a product of Bacillus thuringiensis genes introduced into genetically modified Bt plants. We show by computer simulations that the Bt plant–Bt-resistant insect dynamics resulting from the invasion of the Bt-resistant pests leads to variety of complex changes in the plant–insect biomass, which underlie the dependence of the Bt plant biomass on the duration of the insect reproduction period. We demonstrate that the plant and insect biomass can undergo both regular and irregular oscillations. We show that the character of such oscillations essentially depends on local insect fluxes resulting from inhomogeneous spatial distributions of the insects. In order to characterize the insect diffusion fluxes we introduce a new parameter, the diffusion number Dn. We show that the dependence between a value of Dn and regularity/irregularity of the plant–insect biomass oscillations is governed by a region in the model parameter space. In one of the regions the growth of the value of the diffusion number correlates with the transformation of regular oscillations into irregular ones, while in the neighboring region of the model parameter space the dependence between the character of the plant–insect oscillations and the value of the diffusion number Dn is more complex. The oscillations are irregular if the values of Dn are between 0.05 and 0.25. On either side of this interval the plant–insect oscillations are regular. The complex character of the response of the Bt crop–pest system to the invasion of Bt-resistant insects can lead to significant complications in attempts to regulate the system dynamics.     

我国农业害虫综合防治研究现状与展望

害虫综合防治作为农业生产的一项重要策略,在农业可持续发展中具有举足轻重的作用。近年来,针对我国害虫防治所存在的技术需求,科技部等部门先后通过973计划、863计划、科技支撑计划和农业行业专项等对重要害虫防治研究立项支持。通过这些项目的实施,我国建成了一支由国家和省级科研单位和大学组成的专业科研队伍和研究平台,对害虫监测预警技术、基于生物多样性保护利用的生态调控技术、害虫生物防治技术、化学防治技术、抗虫转基因作物利用技术等方面的研究取得了一系列的重要进展,研究建立了棉花、水稻、玉米、小麦和蔬菜等作物重要害虫的综合防治技术体系,并在农业生产中发挥了重要作用。以基因工程和信息技术为代表的第二次农业技术革命的到来,推动了害虫综合防治的理论发展,为害虫综合防治技术的广泛应用提供了新的机遇。地理信息系统、全球定位系统等信息技术和计算机网络技术的应用,提高了对害虫种群监测和预警的能力和水平,转基因抗虫作物的商业化种植等技术的应用显著增强了对害虫种群的区域性调控效率。针对产业结构调整和全球气候变化所带来的害虫新问题,进一步发展IPM新理论与新技术将成为我国农业昆虫学研究的重要方向之一。     

A degree-day simulation model for the population dynamics of the rice bug, Leptocorisa acuta (Thunb.)

The rice bug, Leptocorisa acuta (Thunb.) is a major pest of the rice crop in India. A computer simulation model of the bug's population dynamics was formulated using the information generated on the thermal requirements of development stages. It is a mechanistic model which follows the state variable–rate variable approach. The model works based on the accumulation of heat units over stage-specific thresholds of development. Validation using light trap catches has shown that the model has satisfactory predictive value. Simulated population dynamics over the years were compared and the influence of global warming on bug population dynamics was predicted. The model can forecast the pest population in the field and help in timely adoption of management practices.     

Using lower trophic level factors to predict outcomes in classical biological control of insect pests

Importation of exotic natural enemies for biological control of insect pests entails risks to the environment. Pre-release estimates of the likelihood of achieving successful control would be helpful in avoiding ineffective importations. Based on strong evidence of multi-trophic level interactions in terrestrial ecosystems, we tested whether variation in ecological and biological factors found at the plant and herbivore trophic levels (levels one and two) could be used to create a simple, empirically based formula, capable of estimating the probability of successful biological control against holometabolous insect pests. We constructed a database consisting of 828 records of biological control attempts against 91 pest insect species and used stepwise logistic regression to test whether five basic features of the ecosystem, crop, and pest (habitat type, crop use, pest order, pest feeding niche, and damage severity) were correlated with rates of successful control. Natural enemy characteristics were not included in the model. The final model included 10 significant independent variables, nine of which were two-way interactions; all five basic ecosystem features appeared in significant interactions. The model provided good estimates of historical success rates against pest species in the data set. In a further test, the model was able to correctly rank amenability to biological control for 10 pest species not included in the original data set. These results provide evidence that lower trophic level factors can be useful in the search for a predictive formula for biological control.     

Structured modeling of recombinant protein production in batch and fed-batch culture of baculovirus-infected insect cells

The infection of insect cells with baculovirus was described in a mathematical model as a part of the structured dynamic model describing whole animal cell metabolism. The model presented here is capable of simulating cell population dynamics, the concentrations of extracellular and intracellularviral components, and the heterologous product titers. The model describes the whole processes of viral infection and theeffect of the infection on the host cell metabolism. Dynamic simulation of the model in batch and fed-batch mode gave goodagreement between model predictions and experimental data. Optimum conditions for insect cell culture and viral infectionin batch and fed-batch culture were studied using the model.