Kovacs Jennifer L, Wolf Candice, Voisin Dené, Wolf Seth
Biology Department, Spelman College, Atlanta, Georgia, United States of America.
Larner College of Medicine, University of Vermont, Burlington, Vermont, United States of America.
PLoS One. 2017 Sep 7;12(9):e0184150. doi: 10.1371/journal.pone.0184150. eCollection 2017.
Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness effects for the larvae of two species of aphidophagous lady beetles that consumed aphids with facultative symbionts. In both species, larvae that consumed aphids with secondary symbionts were significantly less likely to survive to adulthood. In this study we tested whether adult Harmonia axyridis and Hippodamia convergens lady beetles avoided aphids with symbionts in a series of choice experiments. Adults of both lady beetle species were as likely to choose aphids with symbionts as those without, despite the potential negative fitness effects associated with consuming aphids with facultative symbionts. This may suggest that under natural conditions aphid secondary symbionts are not a significant source of selection for predatory lady beetles.
人们发现，可遗传的共生菌能介导宿主物种与其天敌在多种生物中的相互作用。蚜虫、其兼性共生菌及其潜在的适合度效应得到了特别深入的研究。例如，蚜虫兼性共生菌雷吉埃氏菌（Regiella）能保护其宿主免受真菌病原体的感染，而携带汉密尔顿氏菌（Hamiltonella）的蚜虫被寄生蜂寄生的可能性较小。最近的研究还发现，两种食蚜瓢虫的幼虫取食带有兼性共生菌的蚜虫后，适合度会受到负面影响。在这两个物种中，取食带有次生共生菌蚜虫的幼虫存活至成虫期的可能性显著降低。在本研究中，我们通过一系列选择实验测试了成年异色瓢虫（Harmonia axyridis）和多异瓢虫（Hippodamia convergens）是否会避开带有共生菌的蚜虫。尽管取食带有兼性共生菌的蚜虫可能会对适合度产生负面影响，但这两种瓢虫成虫选择带有共生菌蚜虫和不带共生菌蚜虫的可能性是一样的。这可能表明，在自然条件下，蚜虫次生共生菌并非捕食性瓢虫选择猎物的重要因素。
