Prevalence of heritable symbionts in the Parisian Bedbugs (Hemiptera: Cimicidae)

Abstract

Like many insects, the biology of bedbugs is impacted by a range of partner heritable microbes. Three maternally inherited symbionts are recognised, Wolbachia (an obligate partner), Symbiopectobacterium purcelli strain SyClec and Ca. Tisiphia sp. (facultative symbionts typically present in some but not all individuals). Past work had examined these heritable microbes from established laboratory lines, but not from broader field samples. We therefore deployed targeted endpoint PCR assays to determine the symbiont infection status for 50 bedbugs collected from 10 districts of Paris during the 2023 outbreak. All three symbionts were found to be broadly present across C. lectularius samples with the Symbiopectobacterium- Ca. Tisiphia-Wolbachia triple infection most commonly observed. A minority of individuals lacked either one or both facultative symbionts. Five mtDNA haplotypes were observed across the COI barcode region. Triple infections were found in all mtDNA haplotypes, indicating symbiont infection had been circulating over a protracted period of time. We conclude that the Parisian bedbug outbreak was one in which the hosts secondary symbionts were present at high frequency coinfections. Thus, facultative symbionts are an important but uncharacterized component of bedbug populations.