Bacterial endosymbionts of Sitobion avenae: Transmission and ecological interactions

Bacterial endosymbionts of Sitobion avenae: transmission and ecological interactions The primary symbiotic bacterium of aphids is critical for their growth and reproduction, while the secondary bacteria of aphids may interact with other life history traits like performance on host plants, and resistance to natural enemies. Transmission of secondary bacteria among different taxa in nature is still unclear. We studied the abundance of secondary bacteria in populations of Sitobion avenae and investigated the relationship between their abundance and the climatic conditions. We hypothesized that the symbiotic bacteria function differently under different climatic conditions. Vertical and horizontal transmission of the secondary bacteria can take place among and within aphid species and bacteria can also be transmitted to parasitoids. Furthermore, we were able to show that symbiotic bacteria enhance the tolerance to specific climatic condition and this contributes to the acclimation of parasitoids and aphids to different climatic conditions. Furthermore Also, we proved that bacteria-free phages are not responsible for aphid resistance against parasitoids, but in contrast the bacteria positively enhance fitness and hatching under certain climatic conditions. Finally, we investigated the role of secondary bacteria in host plant residence; we hypothesized that these bacteria could detoxify some chemicals which affect the performance of aphids on certain host plants. The ecological implications for interactions between secondary bacteria, aphids, and parasitoids, respectively, are discussed in this study.