Molecular characterisation of Sitobion avenae F. clones and their interaction with different host plants

Abstract

The English grain aphid, Sitobion avenae (F.), is an important pest in agricultural ecosystems, especially in temperate climates on the northern and southern hemisphere. We studied the specialization and adaptability of 10 S. avenae clones in relation to the presence of symbiotic bacteria on different host plants in response to different light regimes. The clones used in the study and their symbiotic bacteria were genetically characterized; eight of them are common in Germany; nine of them have secondary bacterial endosymbionts. We hypothesized that genetic diversity of the clones, their endosymbiotic bacteria, variation in life history traits, light intensity, and water soluble carbohydrates, respectively mediate the interactions between S. avenae clones and their host plants. We found that colour morphs of Sitobion avenae clones are genetically determined and expressed by light intensity. Furthermore light intensity affects the performance of Sitobion avenae clones. Also, we found that water soluble carbohydrates of cocksfoot trigger the specialization in Sitobion avenae clones and the adaptation. Finally we argue that the specialization of Sitobion avenae clones result from interactions between the clones and the host plants, mediated by the specific endosymbiotic bacteria.