AUTHOR=Thongprem Panupong , Evison Sophie E. F. , Hurst Gregory D. D. , Otti Oliver 

TITLE=Transmission, Tropism, and Biological Impacts of Torix Rickettsia in the Common Bed Bug Cimex lectularius (Hemiptera: Cimicidae)

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.608763

DOI=10.3389/fmicb.2020.608763

ISSN=1664-302X

ABSTRACT=<p>The torix group of <italic>Rickettsia</italic> have been recorded from a wide assemblage of invertebrates, but details of transmission and biological impacts on the host have rarely been established. The common bed bug <italic>(Cimex lectularius)</italic> is a hemipteran insect which lives as an obligatory hematophagous pest of humans and is host to a primary <italic>Wolbachia</italic> symbiont and two facultative symbionts, a BEV-like symbiont, and a torix group <italic>Rickettsia</italic>. In this study, we first note the presence of a single <italic>Rickettsia</italic> strain in multiple laboratory bed bug isolates derived from Europe and Africa. Importantly, we discovered that the <italic>Rickettsia</italic> has segregated in two laboratory strains, providing infected and uninfected isogenic lines for study. Crosses with these lines established transmission was purely maternal. Fluorescence <italic>in-situ</italic> hybridization analysis indicates <italic>Rickettsia</italic> infection in oocytes, bacteriomes, and other somatic tissues. We found no evidence that <italic>Rickettsia</italic> infection was associated with sex ratio distortion activity, but <italic>Rickettsia</italic> infected individuals developed from first instar to adult more slowly. The impact of <italic>Rickettsia</italic> on fecundity and fertility resulted in infected females producing fewer fertile eggs. However, we could not find any evidence for cytoplasmic incompatibility associated with <italic>Rickettsia</italic> presence. These data imply the existence of an unknown benefit to <italic>C. lectularius</italic> carrying <italic>Rickettsia</italic> that awaits further research.</p>