不连续气体交换循环呼吸模式下西藏飞蝗和东亚飞蝗的呼吸特征参数

为解析西藏飞蝗对青藏高原干燥低氧环境的呼吸适应机制,本研究比较不连续气体交换循环(discontinuous gas exchange,DGC)呼吸模式下西藏飞蝗Locusta migratoria tibetensis与东亚飞蝗L.m.manilensis的呼吸特征参数。结果表明:西藏飞蝗和东亚飞蝗4、5龄蝗蝻及雄成虫均采用DGC呼吸模式,且雄成虫呼吸速率的峰值和周期比其4、5龄蝗蝻更稳定;西藏飞蝗4龄蝗蝻DGC历时为13.75 min,显著高于东亚飞蝗的6.46 min,而其5龄蝗蝻和雄成虫DGC历时分别为7.46 min和8.53 min,显著低于东亚飞蝗的15.70 min和14.44 min;西藏飞蝗4、5龄蝗蝻的暴发间期历时所占比例分别为7.40%和26.70%,显著低于东亚飞蝗4、5龄蝗蝻(分别为22.20%和67.20%),其雄成虫暴发间期历时所占比例为79.20%,显著高于东亚飞蝗雄成虫的53.60%;西藏飞蝗4、5龄蝗蝻和雄成虫代谢率分别为3.92、3.81和2.90 W/kg,与东亚飞蝗4、5龄蝗蝻和雄成虫差异不显著(分别为4.27、3.45和3.07 W/kg)。西藏飞蝗分布于低氧高海拔青藏高原,其DGC历时和暴发间期历时所占比例异于东亚飞蝗,表明DGC呼吸模式与其对高原环境的适应有关。     

东亚飞蝗FK506结合蛋白基因克隆及其免疫功能分析

为明确东亚飞蝗Locusta migratoria manilensis免疫相关FK506结合蛋白(FK506 binding protein,FKBP)的功能,了解FKBP对金龟子绿僵菌Metarhizium anisopliae侵染东亚飞蝗的影响,分离克隆获得FKBP46基因及其纯化蛋白,采用荧光定量PCR方法测定FKBP46基因在东亚飞蝗成虫不同组织以及不同虫态中肠内的表达量,通过饵剂饲喂方法测定FKBP46蛋白对金龟子绿僵菌致病力及对东亚飞蝗体内保护酶超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、酚氧化酶(phenoloxidase,PO)和解毒酶乙酰胆碱酯酶(acetyl cholinesterase,AchE)活性的影响。结果显示,东亚飞蝗FKBP46基因全长为1200 bp,编码蛋白分子量为55 kD。FKBP46基因在成虫不同组织中均有表达,其中在脂肪体中的相对表达量最高,为体壁中表达量的1.77倍;FKBP46基因在卵期和成虫期的相对表达量较高,分别为1龄蝗蝻期表达量的4.88倍和6.84倍。FKBP46蛋白与金龟子绿僵菌混合饲喂东亚飞蝗,第10天的累计死亡率为85.56%,显著高于金龟子绿僵菌单独处理,而东亚飞蝗体内的保护酶POD、SOD、PO和解毒酶AchE活性均较金龟子绿僵菌单独处理显著降低。表明FKBP46基因能够抑制东亚飞蝗的免疫功能,降低免疫相关保护酶和解毒酶的活性,促进金龟子绿僵菌的侵染。     

海南岛西南部东亚飞蝗的形态及生物学特性

海南岛西有部蝗区东亚飞蝗的前翅长度(E)与后足股节长度(F)的比值,群居型雌成虫为2.02～2.21,雄成虫为1.37～2.18;过渡型雌成虫为2.05～2.17,雄成虫为2.00～2.15;散居型雌成虫为1.91～2.16,雄成虫为1.93～2.08。散居型的E/F比值接近广西、江苏蝗区东亚飞蝗种群,它们应属同一个地理种群。在海南岛西南部东亚飞蝗每年发生4～5世代,世代重叠,无越冬现象。成虫喜欢聚集产卵,容易形成群居型。成虫和蝗蝻都有聚集为害和成群迁移的习性。一般情况下,大田第三、四代京亚飞蝗(约8月至9月发生)数量逐步增加,容易暴发为害。因此重点防治第三代、控制第四代大发生是海南岛西南部蝗区防治东亚飞蝗的重要对策之一。     

低温胁迫对东亚飞蝗存活及其生命特征的影响

研究了各龄期东亚飞蝗分别在-5、0、5℃下的存活时间和各项生命特征。结果表明,低温对东亚飞蝗的存活及其生命特征有一定影响。相同温度下,龄期越大存活时间越长;同一虫态时,温度越高(在一定限度内)存活时间越长;取食的东亚飞蝗成虫比不取食的存活时间明显增加。只有在5℃时才有成虫少量取食,其余低温下和5℃的其他虫态则没有取食;低温处理时成虫几乎不变色,但取出放置在室温(约15℃)时则会有较明显的红色,若放入光照培养箱[(35±2)℃]则会加深红色,若虫的体色则变化不大;低温下的东亚飞蝗活动力明显减弱,多为趴伏状,很少活动,触角有时会轻微活动;死亡时六足紧缩。     

3种生物农药及植物源农药防治东亚飞蝗效果评价

通过2005—2006年在河南省中牟县黄河滩区利用生物农药、植物源农药和常用化学农药防治东亚飞蝗的田间笼罩试验结果表明：30%杀蝗绿僵菌油悬浮剂167ml/hm2、250ml/hm2,药后14d的平均防效可达到90%左右,1%苦皮藤素乳油300ml/hm2、0.3%苦参碱水剂900ml/hm2两个处理的平均防效均达到90%以上,与中毒化学农药氟虫腈的防效接近,而优于低毒化学农药马拉硫磷的防效。鉴于杀蝗绿僵菌、苦皮藤素、苦参碱三种药剂均为低毒的生物农药和植物源农药,可作为替代有机磷和菊酯类农药用于东亚飞蝗的防治。     

高原草地杀蝗菌株嗜烟碱节杆菌Arthrobacter nicotinovorans的分离鉴定及发酵条件优化

从青藏高原采集的土壤中筛选到一株具有杀蝗虫活性的细菌，根据菌株形态和生理生化特征，结合16S rRNA序列分析，鉴定为嗜烟碱节杆菌Arthrobacter nicotinovorans，编号GZ1-6。室内测定了菌株GZ1-6对东亚飞蝗若虫的致病力，结果显示菌株GZ1-6菌悬液对若虫的校正死亡率达到75.56%。测定了碳氮源、温度、初始pH、装液量以及培养时间对菌株GZ1-6生长和杀虫活性的影响，得到菌株GZ1-6分别在以蔗糖和酵母浸膏为碳氮源，pH 7.5、恒温35℃的条件下生长最好，培养2 d，杀蝗活性较优化前提高了7.77%。菌株GZ1-6能够有效侵染东亚飞蝗并将其致死，可作为优良菌株进行杀蝗虫生物农药的进一步研发。     

蝗虫微孢子虫病对东亚飞蝗飞翔能力的影响

采用联机吊飞测试装置，以患有蝗虫微孢子虫病的东亚飞蝗成虫及健康成虫为试虫，进行飞翔能力的比较测定。在18小时测试期间，每头病虫平均飞行864m，健虫为14，279．75m；病虫的平均飞行速度为0．15m／秒，健虫为1．23m／秒；病虫最大持续飞行时间为0．1小时，健虫为6．7小时。结果表明蝗虫微孢子虫病可在很大程度上影响东亚飞蝗成虫的飞翔能力。     

Relationships between spatial pattern of Locusta migratoria manilensis eggpods and soil property variability in coastal areas

Spatial distribution of Locusta migratoria manilensis eggpods and soil properties (water content at 5 cm depth, salinity, organic matter and pH) was studied by integrating geostatistical analysis and GIS techniques. During 2 years of surveys over the entire study area (6000 ha), extensive data (292 regularly grids with 450-m intervals), coupled with intensive data (2601 regularly grids of 0.5-m separation) were used to characterize spatial patterns of L. m. manilensis eggpods and soil property variability and to explore the relationship between them. Semivariograms indicated the eggpods and four soil properties showed high spatial heterogeneity. The spatial distribution of eggpods, at distances ranging from 50-452 m in spatial autocorrelation, was best described using the spherical model. Spatial autocorrelation in total spatial heterogeneity in soil water content at 5 cm, salinity, organic matter and pH were 76.15, 78.04, 57.19 and 61.85%, respectively, and the scales of spatial heterogeneity were 621, 594, 1014 and 1368 m, respectively. GIS assessment maps of eggpods and soil properties, derived by block kriging, displayed patterns of the locust eggpods and soil property variability at an area-wide scale. Most eggpods (66.27% and 72.24% for 2002 and 2003, respectively) were found at the areas with low salinity (<2.0% approximately), suitable water content at 5 cm (10.1-20.0%). No eggpods were found at such areas with high soil water content at 5 cm (>30%) and salinity (>3%). In a way, the spatial distribution pattern of locust eggpods mainly depended on the soil heterogeneity at the study area. t-Tests indicated that sites between with eggpods and without eggpods were significantly different only in soil water content at 5 cm depth and salinity. The results may provide useful information on sampling in the field, forecasting and monitoring locust plague and reclaiming coastal locust breeding areas in China.