Drivers and patterns of microbial community assembly in a Lyme disease vector

Abstract

Vector‐borne diseases constitute a major global health burden and are increasing in geographic range and prevalence. Mounting evidence has demonstrated that the vector microbiome can impact pathogen dynamics, making the microbiome a focal point in vector‐borne disease ecology. However, efforts to generalize preliminary findings across studies and systems and translate these findings into disease control strategies are hindered by a lack of fundamental understanding of the processes shaping the vector microbiome and the interactions therein. Here, we use 16S rRNA sequencing and apply a community ecology framework to analyze microbiome community assembly and interactions in Ixodes pacificus , the Lyme disease vector in the western United States. We find that vertical transmission routes drive population‐level patterns in I. pacificus microbial diversity and composition, but that microbial function and overall abundance do not vary over time or between clutches. Further, we find that the I. pacificus microbiome is not strongly structured based on competition but assembles nonrandomly, potentially due to vector‐specific filtering processes which largely eliminate all but the dominant endosymbiont, Rickettsia . At the scale of the individual I. pacificus , we find support for a highly limited internal microbial community, and hypothesize that the tick endosymbiont may be the most important component of the vector microbiome in influencing pathogen dynamics.

Comparative Microbiome Profiles of Sympatric Tick Species from the Far-Western United States

“…All raw sequence files are accessioned at Sequence Read Archive under BioProject ID PRJNA574713. After removing suspected contaminants and pooling rare genera [11], we found a total of 59 OTUs across all sample types.…”

“…Despite the growing appreciation that tick-associated microbiomes can be important to vector competency and pathogen transmission dynamics [8,9,10,11], the bacterial communities of many tick species, particularly those that are not common human disease vectors, have yet to be investigated. Comparisons of microbiome compositions and endosymbiont patterns between tick species may be a valuable path forward to better understand how tick microbiomes are shaped and perhaps how they influence vector competency [12].…”

“…Amplicon-based next-generation sequencing of the bacterial microbiome, hereafter referred to as the microbiome, is an effective and efficient method that allows for rapid characterization of the entire bacterial community in ticks [13,14]. Despite this recent technological advancement, there have been few studies that have examined how the tick microbiome changes through time or as the tick develops from one life stage to the next, but see [11,15]. Since hard ticks take a single blood meal during each of its post-egg life stages, comparative microbiome analyses of tick life stages could reveal how host blood meal or tick natural history affect the tick microbiome.…”

RNA Viruses of Amblyomma variegatum and Rhipicephalus microplus and Cattle Susceptibility in the French Antilles

“…[17,23]. Bio-ecological parameters may influence virome diversity, such as the tick life cycle or host range [24,[61][62][63][64]. For example, although both tick species are mainly found feeding on ruminants in tropical areas, Amblyomma variegatum and Rhipicephalus microplus present different life cycle strategies.…”

RNA viruses of Amblyomma variegatum and Rhipicephalus microplus and Cattle Susceptibility in the French Antilles

“…[17,23]. Bioecological parameters may influence virome diversity, such as the tick life cycle or host range [24,[61][62][63][64]. For example, although both tick species are mainly found feeding on ruminants in tropical areas, Amblyomma variegatum and Rhipicephalus microplus present different life cycle strategies.…”