间作苜蓿棉田节肢动物群落生态位及时间格局

Niche and temporal pattern of arthropod community in cotton-alfalfa intercrop fields

应用生态位理论对间作苜蓿棉田节肢动物群落进行了系统研究,探讨了棉苜间作棉田主要害虫和天敌的关系。间作苜蓿棉田天敌生态位宽度大于对照棉田,天敌群落在整个调查期内发生的时间长;而对照棉田主要害虫的生态位宽度大于间作苜蓿棉田,害虫对棉花的危害时间长、程度重。间作苜蓿棉田的主要天敌蜘蛛类、多异瓢虫与害虫生态位重叠度大于对照棉田,天敌能更有效地控制棉花害虫的危害。在时间变化过程中,节肢动物群落的时间格局分化明显,将间作苜蓿棉田节肢动物群落在时间动态中的变化分为4个阶段,并结合气候、物候变化,分析了各阶段内主要害虫和天敌的发生特点。

The niches of the main natural enemies and pests in cotton-alfalfa and cotton fields were studied. The natural enemies in cotton-alfalfa intercrop fields had a wider breadth of temporal niche than that in cotton fields. This indicated that there was a longer period of occurrence of natural enemies in the former than in the latter. The main pests in cotton fields had a wider breadth of temporal niche than that in cotton-alfalfa intercrop fields. Araneae spp. and Adonia variegata were the main and key natural enemies within these types of fields. They had a higher overlap in temporal niches with the main pests in cotton-alfalfa intercrop fields indicating that they were more effective for pest control in these fields. The temporal patterns of arthropod communities during the seasons were obvious and could be divided into four stages. Considering the climatic and physiological development, the characteristics of the pests and the natural enemies occurring in each stage were analyzed.