Spatial Distribution Pattern and Sampling Technology of Soritia leptalina Larvae on Quercus aquifolioides

Soritia leptalina endangers mainly Quercus aquifolioides, and it became particularly rampant on Q. aquifolioides in Linzhi area, Tibet. By applying field investigation and lab analysis, this study explored the spatial distribution type and sampling technology of S. leptalina larvae on Q. aquifolioides. The results showed that insect density in the upper layer of tree canopy is higher than that in the middle and lower layer,that in the upper, middle and lower layer of different levels varies greatly, and insect density in different directions follows the sequence: east > north > west > south; spatial distribution of S. leptalina on Q.aquifolioides belongs to aggregation type, larvae show mutual repulsion; aggregation of S. leptalina is the result of biological characteristics of its larvae and the habitat environment; taking Iwa regression model as the basis, the optimal sampling quantity is determined. The study disclosed the spatial distribution rules of S.leptalina on Q. aquifolioides, and on the basis of which could provide the theoretical basis for preventing Q.aquifolioides from the damage of S. leptalina, and also scientific support for studying the spatial distribution pattern of this insect and its natural enemies on other hosts.

川滇高山栎朱颈褐锦斑蛾(鳞翅目:斑蛾科)生物学特性

【目的】2011年至2013年西藏林芝地区川滇高山栎受到食叶害虫朱颈褐锦斑蛾的严重危害,但文献资料仅有该害虫成虫的形态特征和分布记载。研究朱颈褐锦斑蛾的生物学特性和完整的形态特征,以期为该害虫的科学防治提供依据。【方法】2011年3月到2012年3月通过野外实地调查与室内饲养观察相结合的方法,在野外选定3个有代表性的观察基地,在每个基地中选择5株典型受害植株,每株按东、西、南、北方向随机选10枝带虫的川滇高山栎枝条,每枝条用纱网笼罩,每星期观察一次,记录斑蛾习性、形态特征等。2011年3月中旬从观察基地采集斑蛾幼虫带回后置于室外饲养,每星期更换川滇高山栎枝条及水1次,每天观察记录幼虫蜕皮、幼虫体长体宽、取食、结茧、羽化、交配、产卵、孵化、越冬等特性。【结果】朱颈褐锦斑蛾成虫雌雄二型,雄蛾头、胸、腹部黑色,腹部时有蓝色闪光,颈片朱红色,雌蛾头部和颈片朱红色,胸部黄色,腹部黑、黄相间,有蓝色金属闪光;蛹被饺子状丝质茧,茧初期为白色,渐变至土黄色;幼虫蛞蝓型,胸足3对、腹足5对,腹足趾钩二横带;卵长椭圆形,鲜黄色,半透明,孵化前1~2天渐变浅灰色。该害虫在林芝地区1年1代,10月下旬以3~4龄幼虫在栎叶及枝梢隐蔽处越冬,次年3月上旬越冬幼虫开始活动取食,6月下旬至7月上旬老熟幼虫开始结茧化蛹,8月上旬林间蛹开始羽化,8月中旬为羽化高峰期,随后交尾、产卵,卵6~7天后孵化。成虫白天羽化、活动,交尾当天或第2天14:00—17:00产卵,趋光性弱,食性为单食性。【结论】川滇高山栎是林芝地区的主要树种之一,近年来其受朱颈褐锦斑蛾危害严重,根据该虫的生物学特性,每年的3月应在川滇高山栎林中对该虫的危害和虫口数量进行调查,提前采取防治措施可有效防止该害虫对高山栎的严重危害。