利用分子探针法研究稻田蜘蛛集团对褐飞虱的捕食作用

为褐飞虱Nilaparvata lugens（Stal）的绿色防控提供理论参考依据，于2011年和2012年在调查了浙江富阳不同品种稻田褐飞虱和蜘蛛的发生密度后，利用荧光定量PCR分子探针技术分析了9科27种3 807头蜘蛛对褐飞虱的捕食作用。研究结果表明，在水稻Oryza sativa L.不同生育期，稻田总的褐飞虱和蜘蛛密度等参数值均随调查时间呈规律性变化，且在调查时间点间出现了显著性差异（P<0.05）；各科蜘蛛对褐飞虱的捕食阳性率均随水稻生育期的发展呈增加趋势，整体上，狼蛛科Lycosidae、皿蛛科Linyphiidae、球腹蛛科Theridiidae、肖蛸科Tetragnathidae、跳蛛科Salticidae和园蛛科Araneidae捕食率在DAT21，DAT35和DAT77，DAT91之间有显著性差异（P<0.05）；2012年两品种稻田的褐飞虱和蜘蛛密度等参数值均显著高于2011年的值，两年间汕优63（SY63）稻田的褐飞虱和蜘蛛密度均显著高于IR64的密度；2012年各科蜘蛛对褐飞虱的捕食阳性率显著高于2011年的值（P<0.05），且狼蛛科和球腹蛛科对褐飞虱的捕食阳性率在两品种间存在显著性差异（P<0.05）；稻田4种蜘蛛优势种拟环纹豹蛛Pardosa pseudoannulata (Bosenberg & Strand)、八斑球腹蛛Theridion octomaculatum (Boes. et Str.）、食虫瘤胸蛛Oedothorax insecticeps (Boes. et str.)和锥腹肖蛸Tetragnatha maxillosa (Thoren)的捕食阳性率均随褐飞虱种群密度的增加而增加，该捕食功能反应曲线可用非线性模型P=aN/(1+bN)拟合；除锥腹肖蛸外，其它3种的捕食功能反应曲线均呈饱和状态；拟环纹豹蛛捕食褐飞虱的DNA残留量显著高于八斑球腹蛛、锥腹肖蛸和食虫瘤胸蛛的残留量（P<0.05）。本研究结果充分说明稻田各蜘蛛类群对不同生育期、不同品种水稻的褐飞虱均具有较强的捕食作用，是生物防治策略中的重要因素，应加强田间蜘蛛的保护工作和增强自然天敌的控害功能。

Study on predation of spiders onbrown rice planthopper Nilaparvata lugens in rice ecosystem through molecular probe method

Nilaparvata lugens (Stal) (brown rice planthopper, BPH) has been the most serious pest threatening rice production in China. Generalist predators are effective biological control agents in agroecosystems, but the comparative study of predations among main spider species under field conditions has not been fully explored owing to a lack of practical methodology. In order to understand the capability of the spiders to prey on the BPH and provide a theoretical reference for its control, in this study, the densities of BPH and spiders, among crop stages and fields planted with resistant and susceptible varieties were investigated in 2011 and 2012, and 3 807 spiders of dominant species were collected to compare their predations on BPH using DNA-based gut content analysis. The results showed the positive rates for all spider taxa were closely related to prey densities, as well as population dynamics of BPH at different DAT(Days after transplanting), and there were significant differences between the DAT21, DAT35 and DAT77, DAT91. The analysis of density of BPH and spiders between years and varieties showed that the two values were significantly higher in 2012 than 2011, and these were significantly higher in Shan-You 63(SY63) variety than in IR64 variety, respectively. The positive rates for all spider taxa were significantly higher in 2012 than 2011, and these were significantly differences for Lycosidae and Theridiidae between SY63 variety and IR64 variety, respectively. The relationships of positive rates to prey planthopper densities for Pardosa pseudoannulata, Coleosoma octomaculata, Tetragnatha maxillosa Thorell and Ummeliata insecticeps under field conditions could be described using saturated response curves. Quantitative comparisons of predations among the four spider species confirmed that P. pseudoannulata and C. octomaculata were more rapacious than U. insecticeps and T. maxillosa under field conditions. Generalist spiders could follow up BPH population timely, and assemblages of spiders coupled with variety resistance could effectively suppress BPH population. This study highlighted spider importance as the predators of BPH and illustrates the utility of our approach to quantify their trophic linkages between different spider species and BPH in rice ecosystem, and assemblages of spiders coupled with variety resistance could effectively suppress BPH population.