Genomics of insecticide resistance in bed bug Cimex lectularius

In the last few years, the common bed bug Cimex lectularius step out of the shadow as an increasing problem world-wide. Globalization, together with the development of insecticide resistance, are the main reasons underlying its re-emergence. Although the massive use of insecticides in the twentieth century has helped regulate bed bug populations, a phenomenon of resurgence of this species has started in the early 1990s. Insecticide exposure exerts a strong selective pressure, which can facilitate the rapid spread of advantageous mutations in insect populations. In order to achieve effective interventions, these mutations and their diversity must be described. This study aims to identify the genetic determinants involved in Cimex lectularius insecticide resistance. To this end, we performed a genome-wide population-genomic analysis, by comparing the genomic composition of two susceptible strains collected more than 40 years ago, with two recent resistant strains collected after 2010. By performing a genome scan, we identified single nucleotide polymorphism outliers delineating genomic regions associated with insecticide resistance. Additionally, variation in gene copy number was analyzed. We confirmed the involvement of some expected candidate loci together with new candidates for insecticide resistance, which should be further explored.