Ontsira mellipes Ashmead is a gregarious larval ectoparasitoid of woodboring cerambycids. It is native to North America but can readily attack the exotic Asian longhorned beetle, Anoplophora glabripennis (Motschulsky). This study aimed to develop an efficient rearing system for this parasitoid, as a potential novel association biocontrol agent for the beetle, by investigating the effects of different densities of host (two, three, or four larvae) and parasitoid (one, two, three, four, five, six, seven, and eight female wasps) on Ontsira's parasitization efficiency and reproductive outcomes. Results showed that overall parasitism and total numbers of parasitized hosts or progeny produced increased with host and/or parasitoid densities, but the number of parasitized hosts or progeny produced per female parasitoid decreased with parasitoid density at each given host density. Nonlinear regression indicated a consistent pattern of mutual interference as parasitoid density increased. Additional experiments showed that superparasitism (indirect interference) did not occur probably because the parasitoid detects hosts through vibration cues from host feeding and attacked (thus paralyzed) hosts are no longer detectable. Thus, the interference probably results from direct or exploitative competition. Interestingly, female parasitoids responded to increased parasitoid density with a significant increase in clutch size. Overall, per capita parasitization efficiency or reproductive outcomes were optimized at a low parasitoid-host ratio but with large group size of hosts and parasitoids. Therefore, an optimal combination of exposing three or four parasitoids to four hosts is proposed for efficient mass-rearing of this parasitoid.

中文翻译：

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优化寄生蜂和寄主密度以有效饲养亚洲长角甲虫（鞘翅目：天牛科）上的 Ontsira mellipes（膜翅目：甲虫科）

Ontsira mellipes Ashmead 是蛀木天牛的群居幼虫外寄生物。它原产于北美，但很容易攻击异国情调的亚洲长角甲虫 Anoplophora glabripennis (Motschulsky)。本研究旨在通过研究不同密度的寄主（两个、三个或四个幼虫）和寄生物（一个、两个、三个）的影响，为这种寄生物开发一种有效的饲养系统，作为甲虫的潜在新型联合生物防治剂。 、四、五、六、七和八只雌性黄蜂）对 Ontsira 的寄生效率和繁殖结果的影响。结果表明，总体寄生和寄生宿主或后代的总数随着宿主和/或寄生蜂的密度而增加，但是在每个给定的宿主密度下，每个雌性寄生蜂产生的寄生宿主或后代的数量随着寄生蜂密度的增加而减少。随着寄生蜂密度的增加，非线性回归表明存在一致的相互干扰模式。额外的实验表明，超级寄生（间接干扰）没有发生，可能是因为寄生蜂通过来自寄主进食的振动线索来检测寄主，并且不再检测到被攻击（因此瘫痪）的寄主。因此，干扰很可能来自直接或剥削性的竞争。有趣的是，雌性寄生蜂对寄生蜂密度的增加做出了反应，离合器大小显着增加。总体而言，人均寄生效率或繁殖结果在较低的寄生物与寄主比率下进行了优化，但寄主和寄生物的群体规模较大。