春甘蓝田小菜蛾及主要捕食性天敌时空生态位

Spatial and temporal niches of the diamondback moth Plutella xylostella and major predatory enemies in spring cabbage fields

在田间系统调查的基础上,研究了春甘蓝田小菜蛾及主要捕食性天敌的时空生态位。结果表明,小菜蛾的时间生态位宽度较小而空间生态位宽度相对较大,说明小菜蛾种群的发生有高峰期明显和全株为害的特点。小菜蛾的时间动态、空间生态位宽度与种群密度无显著相关性,说明小菜蛾对甘蓝的为害情况比较复杂。田间调查共记录捕食性天敌13种,主要优势种依次为草间钻头蛛、七星瓢虫、血色高亮腹蛛、八斑鞘腹蛛、四点高亮腹蛛和三突花蛛。主要捕食性天敌中,七星瓢虫和三突花蛛与小菜蛾的时空二维生态位重叠度最大,其次为四点高亮腹蛛和血色高亮腹蛛,八斑鞘腹蛛和草间钻头蛛最小。这表明七星瓢虫和三突花蛛对小菜蛾有较好的跟随和潜在控制作用。

Based on a systematic field investigation,the temporal and spatial niches of the diamondback moth （DBM）, Plutella xylostella （Linnaeus）and major predatory enemies in spring cabbage fields were studied.The results showed that the diamondback moth had a narrow temporal niche breadth and a relative wide spatial niche breadth.This implied that the incidence of the diamondback moth had the characteristics of obvious peak-period and whole-plant damage.The tem-poral and spatial niche breadths of DBM had no significant relativity to its own population densities and this implied that the damage of DBM to cabbage was complicated.Thirteen species of predatory enemies were recorded in the field inves-tigation and the major species were Hylyphantes graminicola ,Coccinella septempunctata ,Hypsosinga sanguinea ,Coleoso-ma octomaculatum ,Hypsosinga pygmaea and Misumenops tricuspidatus .Among the major predatory enemies,C .sep-tempunctata and M.tricuspidatus had the biggest temporal＆#215;spatial niche overlap with DBM,followed by H .pygmaea and H .sanguinea ,while C .octomaculatum and H .graminicola had the least overlap.This indicated that C .septem-punctata and M.tricuspidatus had better potential for control of the DBM than the other predators.