The Bacterial Composition Associated With Camponotus Japonicus In Different Seasons And Developmental Stages

Ants are a dominant creature in terrestrial ecosystems, because of their species richnessand extraordinary abundance. Through the history of the Formicidae, ants have built upcomplicate associations with microbes. In particular, gut bacteria have had a strong impact ondietary evolution and species diversification in ant populations and have helped herbivorousants to overcome their dietary deficiencies. Camponotus is the second largest ant genus withnearly2,000species and harbor the obligate intracellular endosymbiotic bacteria ofBlochmannia genus. Blochmannia are involved in nitrogen recycling and upgrading the dietby the synthesis of essential amino acids. Previous studies have revealed that the gut bacterialprofile of C. japonicus presents many other bacteria apart from Blochmannia. In order todetermine if those bacteria changed with season change, and if they present specialcommunity in different developmental stages, we described the gut bacterial community indifferent months of C. japonicus in two colonies (April, June, August and October) and thewhole life circle of C. japonicus (egg, larvae, pupa, major worker, minor worker, male ant andqueen) by using of PCR-RFLP method. The results are as follows:1. Results of gut bacterial composition of C. japonicus in different seasons showed that:gut bacterial communities from the two colonies did not present clear consistent changes withdistinct seasons. Nineteen different bacterial species were determined in eight16S rRNA genelibraries, and they all belong to the phyla of Proteobacteria, Firmicutes, Flavobacteria,Deinococcus-Thermus, Actinobacteria and Bacteroidetes. Proteobacteria was the mostdominant group, accounting for84.7%–100%in all eight clone libraries. Blochmannia is thedominant gut bacteria in two colonies with67.1%–98.8%, and bacteria of Psedomonas andEnterobacter were found in most clone libraries, but other bacteria were distributedsporadically in one to three clone libraries with very low clone numbers. Our results showedthat the gut bacterial communities in two colonies did not change clearly or consistently withthe seasons. This finding suggests that the difference in gut bacterial communities associatedwith C. japonicus is mainly related to the colonies and their environment.2. Results of gut bacterial composition of C. japonicus in different developmental stagesshowed that:①Twenty one bacterial genera were determined in eight16S rRNA geneclone libraries,and they all belonged to Proteobacteria, Firmicutes, Deinococcus-Thermus and Bacteroidetes. ②EndosymbioticBlochmannia sp. was found in all clone libraries, and was thedominant group in clone libraries of egg, pupa, major worker, male ant and queen, accountingfor72.5%－97.9%.③Weissella was the most important bacterial species in the clone library of minor ant,which accounts for70.0%; Firmicutes bacterium was of great predominance in two clonelibrary of larvae, which present73.2%and69.8%, respectively.④Major workers have the highest diversity in terms of bacterial species, whilebacterialcommunities are simple in samples of pupa, egg, male ant and queen.Therefore, bacterial communities significantly shift in different developmental stagesof C. japonicus. In particular, minor worker and larva present unique bacterial communitycomposition, ans this can provide helpful information for understanding the role of bacteriaplaying in the development and caste differentiation of ants.