异色瓢虫成虫对枸杞木虱的捕食作用
Predation of Poratrioza sinica Yang & Li by Harmonia axyridis adults

为测定异色瓢虫Harmonia axyridis（Pallas）成虫对枸杞木虱Paratrioza sinica Yang&Li的捕食作用，在室内测定了异色瓢虫成虫的捕食功能反应、种内干扰、自身密度干扰及捕食偏好性，并通过罩笼试验调查了异色瓢虫成虫对枸杞木虱的田间防控效果。结果表明，异色瓢虫成虫对枸杞木虱的捕食功能反应符合Holling Ⅱ型方程，对卵、1~2龄若虫、3~5龄若虫以及成虫的最大捕食量分别为111.5粒、511.6头、254.2头和113.6头。在异色瓢虫成虫生长周期30 d内能使枸杞木虱总虫口密度下降76.6%；对1~2龄枸杞木虱若虫的搜寻效率为1.01，处理时间为0.0020，均高于卵、3~5龄若虫与成虫；在150头/皿的猎物密度下，异色瓢虫成虫的最大捕食率达85.6%，益害比参考值为1：150。异色瓢虫成虫对枸杞木虱的捕食作用受自身密度的影响显著大于种内干扰；在100头/皿混合猎物密度下，异色瓢虫成虫更偏好捕食木虱成虫，在300头/皿猎物密度下，异色瓢虫成虫更偏向于1~2龄若虫。研究表明，异色瓢虫成虫是具有控制潜力的捕食性天敌，人工释放异色瓢虫成虫可有效防控枸杞木虱。
To study the predation of Poratrioza sinica Yang & Li by Harmonia axyridis adults, the predation functional response, mutual interference, density influence and preference of H. axyridis were investigated in the laboratory, and the control effect of H. axyridis on P. sinica was studied in the field. The results showed that functional response of H. axyridis adults to P. sinica could be fitted by Holling Ⅱ model, and the daily maximum numbers of P. sinica eggs, 1st-2nd instar nymphs, 3rd-5th instar nymphs and adults preyed theoretically by H. axyridis adults were 111.5, 511.6, 254.2 and 113.6, respectively. In 30 days of adult life cycle, the density of P. sinica inside cages was decreased by 76.6% in the fields. The searching efficiency of H. axyridis to P. sinica 1st-2nd instar nymphs was 1.01 and processing time was 0.0020, both of which were better than those of other stages. The maximum rate of P. sinica 1st-2nd instar nymphs preyed was 85.6% as the prey density was 150 heads per dish, and the ratio of predator and prey was 1:150. The density had greater impact on H. axyridis than mutual interference. H. axyridis preferred to P. sinica adults when the density was 100 heads per dish, while it preferred to P. sinica 1st-2nd instar nymphs when the density was 300 head per dish. The study indicated that H. axyridis had the potential as the predator of P. sinica for effective control of P. sinica in the field.