玉米灌浆期3种鳞翅目害虫的空间分布

采用网格式取样200株玉米,整株剖秆调查亚洲玉米螟、桃蛀螟和棉铃虫在玉米上的数量,用地统计学的方法分析和模拟它们在田间的水平分布;采用生态位理论分析3种害虫在玉米植株上的生态位和种间竞争。结果表明,亚洲玉米螟、桃蛀螟和3种鳞翅目害虫整体在玉米田中的水平分布分别适合球形、高斯、球形模型拟合,均属于聚集分布。Kriging插值模拟图显示,亚洲玉米螟和桃蛀螟为核心分布型;在垂直分布上,雌穗上3种害虫数量最多,占总虫量的69.82%。亚洲玉米螟的基础生态位宽度最大,在整株玉米上都可危害;桃蛀螟则主要在玉米中、上部;棉铃虫基础生态位最窄,只在雌穗附近危害。3种害虫在玉米茎秆上种间竞争激烈,异种害虫无法共存;雌穗上种间竞争程度小于茎秆,异种害虫可以共存。

Spatial Distribution of Ostrinia furnacalis, Conogethes punctiferalis and Helicoverpa armigera at Maize Filling Stage

Two hundreds of maize were selected by the grid-cell sampling method. The number of Ostrinia fur- nacalis(Guenée), Conogethes punctiferalis(Guenée) and Helicoverpa armigera(Hübner) in maize plants was investigat- ed by splitting the stalks of maize. The geostatistics method was used to evaluate the horizontal distribution of these three pests. In addition, the ecological niche of three pests in maize plants and their interspecific competition were analyzed according to niche theory. The results showed that the horizontal distribution of O. furnacalis, C. punctifera- lis and these three pests in maize field were suitable to fit with spherical, gaussian and spherical model, respective- ly, which all belong to a clumped distribution. Kriging interpolation simulation showed O. furnacalis and C. punctife-ralis as the core distribution pattern. On the vertical dimension, maize ear was the favorite position for the majority of pests, with larvae accounting for 69.82% of the total amount of three pests. O. furnacalis had the largest funda- mental niche breadth, and could damage the whole maize plant. However, the fundamental niche of C. punctiferalis was mainly on the middle and upper part of a maize plant. H. armigera had the narrowest fundamental niche, which was only the part near ear. Our results showed that there was an intense competition among 3 pest species in maize stalk, where pest species could not coexist.