Abstract
Host plants play a vital role in insect population differentiation, while symbiotic associations between bacteria and insects are ubiquitous in nature. However, existing studies have given limited attention to the connection between host-related differentiation and symbiotic bacterial communities in phytophagous insects. In this study, we collected 58 samples of Aphis odinae from different host plants in southern China and constructed phylogenetic trees to investigate their differentiation in relation to host plants. We also selected aphid samples from the five most preferred host plants and analyzed their symbiotic bacterial composition using Illumina sequencing of the V3-V4 hypervariable region of the 16S rRNA gene. The phylogeny and symbiotic bacterial community structure of A. odinae populations on different host plants showed that samples from Triadica sebifera (Euphorbiaceae) had a consistent presence of Wolbachia as the predominant secondary symbiont and suggested the possibility of undergoing differentiation. Conversely, although differentiation was observed in samples from Rhus chinensis (Anacardiaceae), no consistent presence of predominant secondary symbionts was found. Additionally, the samples from Heptapleurum heptaphyllum (Araliaceae) consistently carried Serratia, but no host differentiation was evident. In summary, this study reveals a partial correspondence between symbiotic bacterial communities and host-related differentiation in A. odinae. The findings contribute to our understanding of the microevolutionary influencing the macroevolutionary relationships between bacterial symbionts and phytophagous insects. The identification of specific symbionts associated with host-related differentiation provides valuable insights into the intricate dynamics of insect-bacteria interactions.