Most of us are quite content to share our beds with a partner or a kitty, but are less inclined to extend the same warm welcome to the common bedbug, Cimex lectularius. These parasitic insects, which feed exclusively on blood, have undergone a population explosion since the mid-1990’s, with infestations recently hitting the headlines all over the globe. Buildings full of warm and cosy human nests, such as blocks of flats and hotels, are enticing bedbug havens. Although pesticide sprays are deployed as control measures, research from Denmark has already suggested that this isn’t a viable long-term solution, since bedbugs quickly develop resistance to common insecticides like chlorpyrifos, permethrin and deltamethrin.

New research from a team at the University of Kentucky, USA, has now revealed how bedbugs evolve such resistance. Pesticide-resistant bedbugs can exhibit changes in up to fourteen key sections of DNA compared to those that are pesticide-susceptible. Individual bedbugs isolated from 21 test locations across the midwestern USA (including LA, Cincinnati, Lexington, Plainview, Louisville and Chicago) all had at least two of these fourteen genetic modifications, most of which bolstered the shell, stopping or slowing chemical penetration. Changes in other genes increased the activity of pesticide-detoxifying metabolic pathways, or improved the ability of bedbug nerve cells to spit out chemicals targeted to the central nervous system. This knowledge could help to devise useful new bedbug control strategies.

Zhu F, Gujar H, Gordon JR, Haynes KF, Potter MF, & Palli SR (2013). Bed bugs evolved unique adaptive strategy to resist pyrethroid insecticides. Scientific reports, 3 PMID: 23492626

Kilpinen, O., Vagn Jensen, K.-M., & Kristensen, M. (2008). Bed Bug Problems in Denmark, with a European Perspective Proceedings of the Sixth International Conference on Urban Pests