Microbiota assessment across different developmental stages of Dermacentor silvarum (Acari: Ixodidae) revealed stage-specific signatures.

Dermacentor silvarum is an important vector of tick-borne pathogens. The microbiota of ticks has been recognized to influence their development, fitness, and reproduction as well as the acquisition, establishment and transmission of pathogens. Eggs, larvae, nymphs and adults (females and males) of D. silvarum were used in this study to evaluate microbial community and diversity across different developmental stages. The results demonstrated that some developmental stages host different bacterial species, confirming that each stage of development could have a specific associated microbiota. Proteobacteria was the dominant phylum in most stages, while Actinobacteria was the most abundant in nymphs. The abundance of Brevibacterium significantly increased from the egg stage to the following stages, and there was a sharp increase in the abundance of this genus among nymphs. Eggs showed the highest microbial richness and diversity, and the microbial community of eggs exhibited high similarity to that of females. Moreover, the high abundance of Coxiella in eggs and females further indicated that members of this genus are vertically transmitted symbionts. Nymphs showed a microbial composition distinct from those of the other stages, and the microbial community associated with males possessed higher species richness and greater bacterial diversity than that of females. Further investigations are needed to determine the functions of the microbiota and provide information enabling a better understanding of the diversity of the microbial community at different life stages.