棉蚜及其捕食性天敌时空生态位研究

研究结果表明，棉蚜的时间生态位宽度较小而空间生态位宽度较大，说明棉蚜种群的发生有高峰期明显和全株为害的特点．棉蚜的时动空间生态位宽度与种群密度无相关性，说明棉蚜的为害较复杂．捕食性天敌中草间小黑蛛和龟纹瓢虫的时空生态位宽度较大，说明它们发生期较长、分布范围较广．八斑球腹蛛和龟纹瓢虫与棉蚜的时间生态位重叠度较大，八斑球腹蛛和草间小黑蛛与棉蚜的空间生态位重量度较大．与棉蚜的时间×空间生态位重叠度，八斑球腹蛛＞龟纹瓢虫＞草间小黑蛛＞其它天敌合计＞三色长蝽＞三突花蛛＞小花蝽，这一结果同棉蚜与捕食性天敌数量的关联度大小排序相一致，表明捕食性天敌与棉蚜的时间同步和空间同线性与天敌的捕食作用密切相关．

Spatial and temporal niches of Aphis gossypii and its predatory enemies.

The research results showed that Aphis gossypii had a narrow temporal niche breadth and a wide spatial niche breadth. This implied that the occurrence of A. gossypii population had the characteristics of obvious peak-period and whole-plant damage. The temporal-dynamic spatial niche breadthes of A. gossypii had no relativity to its own population densities. This implied that the damage of A. gossypii was complicated. Among the predatory enemies, Erigonidium graminicola and Propylaea japonica had wider temporal and spatial niche breadthes than other predatory enemies, and it meant that the above two enemies had longer period of occurrence and wider range of distribution. The temporal x spatial niche overlap of the predatory enemies with A. gossypii was in order of Theridium octomaculatum > P. japonica > E. graminicola > total of other enemies > Geocoris ochropterus > Misumenops tricuspidatus > Orius minutes, and the other was consistent with that of relational grades of A. gossypii and its predatory enemy populations. This result showed that the sympatry and synchronism of predatory enemies with A. gossypii had close relation to the predatory effect of the natural enemies.