A 454 survey of the community composition and core microbiome of the common bed bug, Cimex lectularius, reveals significant microbial community structure across an urban landscape

1 Title: A 454 survey of the community composition and core microbiome of the common 2 bed bug, Cimex lectularius, reveals significant microbial community structure across an 3 urban landscape 4 5 6 Abstract 14 15 Elucidating the spatial dynamic and core constituents of the microbial communities found 16 in association with arthropod hosts is of crucial importance for insects that may vector 17 human or agricultural pathogens. The hematophagous Cimex lectularius, known as the 18 common bed bug, has made a recent resurgence in North America, as well as worldwide, 19 potentially owing to increased travel and resistance to insecticides. A comprehensive 20 survey of the bed bug microbiome has not been performed to date, nor has an assessment 21 of the spatial dynamics of its microbiome. Here we present a survey of bed bug microbial 22 communities by amplifying the V4-­‐V6 hypervariable region of the 16S rDNA gene region 23 followed by 454 Titanium sequencing using 31 individuals from eight natural populations 24 collected from residences in Cincinnati, OH. Across all samples, 97% of the microbial 25 community is made up of two dominant OTUs identified as the α-­‐proteobacterium 26 Wolbachia and an unnamed γ-­‐proteobacterium from the Enterobacteriaceae. Microbial 27 communities varied among host populations for measures of community diversity and 28 exhibited significant population structure. We also uncovered a strong negative correlation 29 in the abundance of the two dominant OTUs, suggesting they may fulfill similar roles as 30 nutritional mutualists. This broad survey represents the most comprehensive assessment, 31 to date, of the microbes that associate with bed bugs, and uncovers evidence for potential 32 antagonism between the two dominant members of the bed bug microbiome. 33 34 3 Introduction 34 35 The interactions between microbes and their insect hosts can range from beneficial 36