State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2010 Jun 10;5(6):e11064. doi: 10.1371/journal.pone.0011064.
In a tritrophic system formed by a plant, an herbivore and a natural enemy, each component has its own biological rhythm. However, the rhythm correlations among the three levels and the underlying mechanisms in any tritrophic system are largely unknown. Here, we report that the rhythms exhibited bidirectional correlations in a model tritrophic system involving a lima bean, a pea leafminer and a parasitoid. From the bottom-up perspective, the rhythm was initiated from herbivore feeding, which triggered the rhythms of volatile emissions; then the rhythmic pattern of parasitoid activities was affected, and these rhythms were synchronized by a light switch signal. Increased volatile concentration can enhance the intensity of parasitoid locomotion and oviposition only under light. From the top-down perspective, naive and oviposition-experienced parasitoids were able to utilize the different volatile rhythm information from the damaged plant to locate host leafminers respectively. Our results indicated that the three interacting organisms in this system can achieve rhythmic functional synchronization under a natural light-dark photoperiod, but not under constant light or darkness. These findings provide new insight into the rhythm synchronization of three key players that contribute to the utilization of light and chemical signals, and our results may be used as potential approaches for manipulating natural enemies.
在由植物、草食动物和天敌组成的三级营养系统中，每个组成部分都有自己的生物节律。然而，三级营养系统中三个层次之间的节律相关性及其潜在机制在很大程度上是未知的。在这里，我们报告了在涉及利马豆、豌豆叶蝉和寄生蜂的模型三级营养系统中，三个层次之间的节律表现出双向相关性。从下到上的角度来看，节律是由草食动物的取食引发的，这触发了挥发性物质排放的节律；然后，寄生蜂活动的节律模式受到影响，这些节律通过光开关信号同步。在光照下，增加挥发性浓度只会增强寄生蜂的运动和产卵强度。从上到下的角度来看，未接触过和接触过产卵的寄生蜂能够分别利用受损植物的不同挥发性节律信息来定位宿主叶蝉。我们的结果表明，在自然的明暗光周期下，该系统中的三个相互作用的生物能够实现节律功能同步，但在持续光照或黑暗中则不能。这些发现为三个关键参与者的节律同步提供了新的见解，这有助于利用光和化学信号，我们的结果可能被用作操纵天敌的潜在方法。
