Effect of Cardinium Infection on the Probing Behavior of Bemisia tabaci (Hemiptera: Aleyrodidae) MED

Facultative endosymbionts can affect the growth, physiology, and behavior of their arthropod hosts. There are several endosymbionts in the invasive whitefly Bemisia tabaci Mediterranean (MED, Q biotype) that influence host fitness by altering stylet probing behavior. We investigated the probing behavior of B. tabaci MED infected with the facultative endosymbiont Candidatus Cardinium hertigii (Cardinium (Sphingobacteriales: Flexibacteraceae)). We generated genetically similar Cardinium-infected (C^*+) and uninfected (C^-) clonal sublines and analyzed the probing behavior of newly emerged adult on cotton (Malvales: Malvaceae), Gossypium hirsutum L., using electropenetrography (EPG). The C^- subline demonstrated a longer duration of E2 (2.81-fold) and more events of E2 (2.22-fold) than the C^*+ subline, indicating a greater level of sustained ingestion of plant phloem. These findings provide insight into the fitness costs (fitness of a particular genotype is lower than the average fitness of the population) of the Cardinium-infected B. tabaci.     

大学图书馆学生读者借阅过程中不良行为分析

现在大学图书馆多数实行了全开架超市化管理模式,读者享受到全开架外借、阅览一体化服务,方便了读者借阅,同时读者的一些不良性行为也时有发生。分析了读者不良行为的表现,产生的原因,并对图书馆如何避免和防止读者不良行为的发生进行了分析和探讨。     

南蝠捕食行为及其对稻田虫害发生的影响

为了解南蝠(Ia io)在维持稻田生态系统稳定性中的作用,采用粪便分析和直观法,研究了南蝠的捕食行为及其对稻田虫害发生的影响。结果表明:南蝠是控制农田害虫的有效天敌之一,在其捕食区域内稻田病虫害较轻,2～3km半径区域水稻的平均产量比6～7km半径区域增产98.2kg/667m2;南蝠的食物组成除鸟类外,还有鞘翅目、鳞翅目、半翅目、直翅目、膜翅目和蜱螨等昆虫/生物,多数种类昆虫均是水稻害虫或病害的传播者。南蝠在维护稻田生态系统稳定性和提高农作物产量方面具有重要的作用。     

网络环境下农民日常生活信息搜寻行为模式研究

通过调查问卷的方式搜集数据,研究网络环境下农民日常生活信息的获取渠道、日常信息的准确性及有效性,结果表明,不同性别、年龄和学历的农民在日常生活信息的来源、判断信息的准确性和判断信息的有效性方面存在巨大差异,年龄在18～45岁范围内的男性更倾向于从网络获得信息并应用于生活中。该研究对设计农村用户产品营销策略、传播农业科技知识和政策的传达等方面有重要参考作用。     

Defense mechanisms in the sapwood of living trees against microbial infection

When pathogenic microorganisms invade living sapwood of woody plants, a series of defense responses occurs at the lesion margin. Putative active defense mechanisms include constitutive and induced inhibitory compounds, cell wall alterations, and occlusion of xylem elements. Active defenses play an important role in the sapwood, while constitutive and induced microenvironmental conditions in the wood might also constrain pathogen development. It is necessary to develop a unified understanding, in which these factors could act synergistically and provide effective defense barriers.     

Shear creep and mechanosorptive behavior of nail-plate-jointed laminated-veneer lumber

The objective of this research was to evaluate the mechanosorptive deflection of shear creep of nail-plate-jointed laminated-veneer lumber. The joint was composed of steel gusset and nails, 40 mm in length and 2.8 mm in diameter (Zn40). The specimens were loaded parallel (PA) and perpendicular (PE) to the grain. Shearing loads applied were 50 and 100kgf, and the load levels were 11% and 22% (PA) and 7% and 14% (PE) of the maximum strength obtained from static testing. The creep test specimens were loaded for 1500h. A few general conclusions could be drawn from this study: The mechanosorptive deflection (_ms) is defined as _ms = _t — (_c + _sh) — _o, where _t, is total deflection, _c is pure creep, _sh is shrinkage-swelling behavior, and _o is the initial deflection. Changes in relative humidity may cause more severe creep deflection than constant humidity, especially during the drying process. The mechanosorptive deflection is greater at the lower load level than that at the higher load level. The mechanosorptive effects seem to be somewhat more resistant in the parallel direction than in the perpendicular direction.     

超临界CO2萃取五角枫挥发物及其对光肩星天牛的嗅觉行为反应

光肩星天牛(Anoplophora glabripennis)是我国重要的多食性蛀干害虫,已造成重大的经济损失(黄竞芳等,1991;1992;阎凤鸣,2002).在光肩星天牛寻找寄主植物的识别过程中,由寄主植物释放的挥发性信息化学物质起着重要的通讯引导作用(景谦平等,2001).     

喷蒸真空热压刨花板板坯内部的温度场特性

研究了喷蒸真空热压杨木大片刨花板坯内部的温度分布特征。实验结果表明,平行于热压板的板坯中心平面内的温度分布比较均匀,沿板坯厚度方向各点的温度分布差异较大。在喷蒸真空热压过程中,板坯内部的温度上升速率比传统热压快得多。     

夏季森林地下火分类及火行为特点

通过对黑龙江省近10年来各地发生的夏季森林地下火进行实地踏查和研究分析，对地下火的分类和夏季森林地下火蔓延规律、日变化规律、火行为特点进行了研究。