ABSTRACT Considering the importance of natural enemies in the integrated management programme of Bemisia tabaci (Gennadius), in the current study we evaluated the biocontrol potential of two predatory beetles Delphastus catalinae Horn and D. pallidus LeConte against Middle Eastern Asia Minor 1 (MEAM1 or biotype B) and Mediterranean (MED or biotype Q) whiteflies, the two most notorious representatives of the B. tabaci species complex. The functional responses of two predators at prey densities ranging from 20 to 120 whitefly eggs/leaf disc, and prey-stage preferences with different ratios of whitefly eggs and nymphs of two predatory beetles were investigated under laboratory conditions. Both beetle species showed Type II functional response with respect to MEAM1 and MED eggs, determined by the logistic regression model. Based on the observed predation parameters (handling time, attack rate, and the number of eggs consumed), D. catalinae seemed to be a more suitable biocontrol candidate for whitefly pests. Results indicated that both the beetle species preferred whitefly eggs over the early nymphal instars and they could consume >50 eggs per day. Although these findings are promising, their feeding potential needs to be evaluated further under greenhouse and semi-field conditions to confirm their efficacy against MEAM1 and MED whitefly.

中文翻译：

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Delphastus catalinae 和 D. pallidus (Coleoptera: Coccinellidae) 对 Bemisia tabaci (Hemiptera: Aleyrodidae) 的功能反应和猎物阶段偏好

摘要 考虑到天敌在烟粉虱 (Gennadius) 综合管理计划中的重要性，在当前的研究中，我们评估了两种掠食性甲虫 Delphastus catalinae Horn 和 D. pallidus LeConte 对中东小亚细亚 1 (MEAM1 或生物型B) 和地中海（MED 或生物型 Q）粉虱，这是烟粉虱物种复合体的两个最臭名昭著的代表。在实验室条件下，研究了两种捕食者在 20 到 120 个粉虱卵/叶盘的猎物密度下的功能反应，以及粉虱卵和两种掠食性甲虫若虫的不同比例的捕食阶段偏好。两种甲虫物种都显示出对 MEAM1 和 MED 卵的 II 型功能反应，由逻辑回归模型确定。根据观察到的捕食参数（处理时间、攻击率和消耗的卵数），D. catlinae 似乎是粉虱害虫更合适的生物防治候选者。结果表明，这两种甲虫物种比早期若虫龄期更喜欢粉虱卵，它们每天可以消耗 > 50 个卵。尽管这些发现很有希望，但需要在温室和半田条件下进一步评估它们的摄食潜力，以确认它们对 MEAM1 和 MED 粉虱的功效。