Surface wettability affects attachment of male bed bugs Cimex lectularius to rough Perspex substrates

Insects attach to various surfaces that differ, among others, in roughness and wettability. Identifying surface characteristics that allow or prevent insects from attaching are an important research avenue of pest control. Here we take an experimental approach to analyse the attachment of common bed bugs, Cimex lectularius Linnaeus (1758), to Perspex (PMMA) substrates. We construct a reliable centrifuge device that allows the measurement of attachment forces at substrate roughnesses, Ra, between 0.02 and 1.3 mu m and at two wettabilities. Our results suggest that bed bug attachment to surfaces is minimal at a substrate roughness of 0.2 and 0.4 mu m on normal PMMA, where the lowest attachment force was 0.8 mN and the safety factor 15. At lower and higher roughness, attachment forces were higher and the safety factor increased to a maximum of 133. On PMMA that was made superhydrophobic by spray-coating, attachment was lowest (0.2 mN) at the lowest roughness and continuously increased with increasing roughness, reaching 2.5 mN and a safety factor of 46. For every roughness, attachment forces were lower on superhydrophobic than on normal PMMA. This knowledge may inspire the development of repelling substrates for bed bug control.