螺旋粉虱在羊蹄甲上的空间格局

螺旋粉虱(Aleurodicus dispersus Russell)是一种新的入侵害虫,应用聚集强度指数和地学统计学研究其卵、2～4龄若虫和成虫在海南岛儋州地区羊蹄甲(Bauhinia variegata L.)上的空间分布情况.结果表明:在垂直分布上,不同时期各虫态主要分布在植株的下层即老叶上:在水平分布上,不同时期3种虫态在羊蹄甲上均为聚集分布,它们的变异曲线均为高斯模型.在高密度下卵和成虫及低密度下成虫的空间异质性是由随机因素引起,而高密度下2～4龄若虫及低密度下卵和2～4龄若虫的空间异质性是由空间的自相关因素引起.利用Kriging插值法,由地学统计学软件Surfer 8.0绘制的密度等值线图可直观地反映螺旋粉虱在羊蹄甲上的空间分布.

Spatial Pattern of Aleurodicus dispersus Russell on Bauhinia variegata L.

The spiraling whitefly Aleurodicus dispersus Russell(Homoptera: Aleyrodidae)is a new invasive pest. Aggregation intensity index and geostatistics methods were used to analyze the spatial distribution pattern of its eggs, 2~ 4 instars nymphs and adults on Bauhinia variegata L in Danzhou, Hainan. The results showed that A. dispersus at various morphological stages was vertically distributed in different time mainly on the lower layers of the plant or old leaves, and horizontally aggregately distributed on B. variegata at different times, with their best models fit to the semivariograms being the Gaussian model. Spatial heterogeneity of the eggs and adults in higher density, adults in lower density were caused by random factors, but spatial variability of the 2~4 instars nymphs in the higher density, and of the eggs and 2~4 instars nymphs in the lower density were spatially autocorrelated. The isoclines maps of A. dispersus on B. variegatablakeana were created by the geostatistical software Surfer 8.0 with Kriging interpolation, and the resulting maps gave a direct view about the spatial patterns.