拟小食螨瓢虫对木薯朱砂叶螨的行为反应与空间分布相关性

拟小食螨瓢虫对小薯上朱砂叶螨种群数量具有一定的控制作用.为研究利用拟小食螨瓢虫控制朱砂叶螨,在观察拟小食螨瓢虫成虫对朱砂叶螨成、若螨和卵的逐日捕食量基础上,测定拟小食螨瓢虫对不同密度朱砂叶螨+螨害木薯叶VS健康木薯叶的选择性,调查拟小食螨瓢虫和朱砂叶螨在木薯上的空间分布相关性.结果表明:①拟小食螨瓢虫羽化后第3天对朱砂叶螨成、若螨和卵的捕食量达最大值,并趋于稳定.②当朱砂叶螨若螨和成螨密度为30头/叶及40头/叶时,拟小食螨瓢虫显著地趋向朱砂叶螨+螨害木薯叶复合体;(③当朱砂叶螨若螨和成螨在木薯上的分布数量分别为41.90头和32.60头时,拟小食螨瓢虫在木薯上的分布数壁达最大;(④天敌拟小食螨瓢虫对木薯朱砂叶螨的行为选择与二者在木薯上的空间分布之间存在正相关关系.本研究结果可为探讨拟小食螨瓢虫对木薯朱砂叶螨的选择机制,以便更好地利用其控制木薯朱砂叶螨为害提供科学依据.

Behavior Responses of Stethorus parapauperculus to Tetranychus cinnabarinus Infesting Cassava and Their Spatial Distribution

Stethorus parapauperculus, one of the natural enemys of the red spider mite (Tetranychus cinnabarinus), have a good control effect on the population of T. cinnabarinus. For better use of S. parapauperculus to control T. cinnabarinus, the adults, nymphs and eggs of T. cinnabarinus fed by S. parapauperculus were observed in daily terms, based on which behavior responses of 5. parapauperculus on different densities of tetranychus cinnabarinus + cassava leaves infested as well as on healthy leaves were determined, and the spatial distribution of 5. parapauperculus and t. cinnabarinus on the cassava leaves in the field were measured. The number of adults, nymphs and eggs of T. cinnabarinus fed by 5. parapauperculus was the highest at day 3 after S. parapauperculus emerged into adults, and then tended to be stable. S. parapauperculus had a significant behavior preference to the combination of T. cinnabarinus + infested cassava leaves at the mite densities of 30 nymphs/leaf and 40 adults/leaf. The number of S. parapauperculus distributed on cassava leaves was the highest in the field when T. cinnabarinus was distributed on cassava leaves at the intensities of 41.90 nymphs and 32.60 adults. The behavior preference of the enemy to the mite was positively correlated with their spatial distribution in cassava leaves. The results provided a reference to explore the mechanism of behavior preference of S. parapauperculus to T. cinnabarinus in cassava leaves and to make better use of the natural enemy to control the mite.