Females of host-feeding parasitic wasps often partition hosts of different stages for feeding and parasitization, but the underlying behavioral mechanisms are largely unknown, making it difficult to evaluate parasitoid–host interactions and their effects on biological control success. Tamarixia triozae (Burks) is an ectoparasitoid of tomato-potato psyllid Bactericera cockerelli (Šulc), which utilizes nymphs and kills them both by parasitization and host feeding. In this study, we exposed female wasps to 1st- to 5th-instar psyllid nymphs simultaneously and made 13-h continuous video recording of parasitoid–host interactions. We then quantified host stage-dependent handling time for feeding and oviposition and behaviors of parasitoid attacks and host defenses from encountering to successful feeding and oviposition. Female wasps were more likely to encounter and evaluate older hosts. However, the encounter and evaluation did not necessarily result in the success of feeding and oviposition. Our findings suggest that (i) T. triozae continues to assess the host using its ovipositor after the evaluation phase, (ii) females prefer the mid-aged hosts for feeding piercing and feeding and the later instars for oviposition probing and oviposition, (iii) the combination of stage-specific host nutrition value, integument thickness and defense behavior determines the success of feeding attacks, and (iv) the optimal host resource for parasitoid offspring fitness defines host stage selection for oviposition. This study contributes to our understanding of parasitoid–host interactions and mechanisms behind host stage selections.

中文翻译：

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与柽柳属（膜翅目：Eulophidae）-Bactericera cockerelli（半翅目：Triozidae）系统中寄主阶段相关的拟寄生物-宿主相互作用行为

取食寄主的雌性寄生蜂经常将寄主划分为不同阶段进行取食和寄生，但其潜在的行为机制在很大程度上尚不清楚，因此很难评估寄生蜂与寄主之间的相互作用及其对生物防治成功的影响。Tamarixia triozae (Burks) 是番茄马铃薯木虱 Bactericera cockerelli (Šulc) 的外寄生物，它利用若虫并通过寄生和寄主摄食来杀死它们。在这项研究中，我们将雌性黄蜂同时暴露于 1 至 5 龄木虱若虫中，并对寄生蜂与宿主的相互作用进行了 13 小时的连续视频记录。然后，我们量化了依赖于宿主阶段的取食和产卵处理时间，以及从遭遇到成功取食和产卵的寄生物攻击和宿主防御行为。雌性黄蜂更有可能遇到并评估年长的宿主。然而，遭遇和评估并不一定导致取食和产卵成功。我们的研究结果表明，(i) T. triozae 在评估阶段后继续使用其产卵器评估宿主，(ii) 雌性更喜欢中年宿主进行刺穿和取食，而较晚龄的宿主则进行产卵探测和产卵，(iii) ）特定阶段宿主营养价值、外皮厚度和防御行为的组合决定了摄食攻击的成功，以及（iv）寄生蜂后代适应性的最佳宿主资源定义了产卵的宿主阶段选择。这项研究有助于我们了解寄生蜂与宿主的相互作用以及宿主阶段选择背后的机制。