Symbiotic Bacterial Communities of Insects Feeding on the Same Plant Lineage: Distinct Composition but Congruent Function.

Abstract

The health and diversity of plant-feeding insects are strictly linked to their host plants and mutualistic symbionts. However, the study of bacterial symbionts within different insects on the same plant lineage is very limited. This study aimed to investigate the bacterial diversity in insect samples that exclusively feed on Bambusa, representing three insect orders, Hemiptera, Lepidoptera, and Blattodea, each exhibiting distinct dietary preferences. The bacterial community was predominantly composed of Proteobacteria, Spirochaetota, Cyanobacteria, Firmicutes, and Bacteroidota. The study found significant variations in symbiotic organisms among three insect orders: hemipterans had Buchnera, lepidopterans had Acinetobacter, and blattodean had Treponema. Furthermore, the dietary preferences of these insects played a pivotal role in shaping the symbiotic relationship of insects. Proteobacteria are prevalent in sap feeders, Spirochaetota dominate in stem feeders, and Cyanobacteria are abundant in leaf feeders. Seasonal influences also affect bacterial symbionts in P. bambucicola, with Serratia present exclusively in winter. We also observed that the bacterial composition varies across all samples, but their core functions appear to be consistent. This highlights the complex relationship between host phylogeny and diet, with phylogeny being the primary driver, shaping adaptations to specialized diets.