Some parasitoids oviposit in nonhosts. Parasitization of nonhosts potentially wastes gametes, risks the death of offspring, and reduces fitness. Associative learning, a strategy for efficient reproduction, has been observed in various parasitoid species. We conducted two types of experiments to reveal whether larval parasitoid wasps, Cotesia kariyai (Hymenoptera: Braconidae), learn associatively by ovipositing in nonhosts. In dissection experiments, we found wasp eggs in both host [Mythimna separata (Lepidoptera: Noctuidae)] and nonhost [Spodoptera litura (Lepidoptera: Noctuidae)] caterpillars. However, the mean number of eggs in nonhosts was significantly smaller than in hosts. In oviposition experiments, most naive C. kariyai females attacked both hosts and nonhosts. On the other hand, wasps that had previously attacked nonhosts tended to avoid them thereafter. We conclude that C. kariyai females may be able to detect and identify nonhost metabolites and/or cuticular hydrocarbons. Negative associative learning enhances C. kariyai reproductive success when hunting in complex host habitats.

中文翻译：

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幼虫寄生蜂 Cotesia kariyai 在非寄主 Spodoptera litura 上的产卵经验，可以阻止随后的攻击

一些寄生蜂在非寄主体内排卵。非寄主的寄生可能会浪费配子，冒着后代死亡的风险，并降低适应性。联想学习是一种有效繁殖的策略，已在各种寄生物种中观察到。我们进行了两种类型的实验，以揭示幼虫寄生蜂 Cotesia kariyai（膜翅目：蜂科）是否通过在非寄主中产卵来进行关联学习。在解剖实验中，我们在宿主 [Mythimna separata ( Lepidoptera: Noctuidae)] 和非寄主 [Spodoptera litura ( Lepidoptera: Noctuidae)] 毛虫中发现了黄蜂卵。然而，非寄主的平均卵数明显少于寄主。在产卵实验中，大多数幼稚的 C. kariyai 雌性都会攻击寄主和非寄主。另一方面，以前攻击过非寄主的黄蜂此后往往会避开它们。我们得出结论，C. kariyai 雌性可能能够检测和识别非寄主代谢物和/或表皮碳氢化合物。在复杂的寄主栖息地狩猎时，负联想学习提高了 C. kariyai 的繁殖成功率。