Studies On Insecticide Resistance In Australian Bed Bugs, Cimex Spp. (Hemiptera: Cimicidae)

Abstract:
To investigate insecticide resistance in modern field populations of bed bugs in Australia, a program to collect and screen field specimens was initiated. Thirty-five bed bug strains (a mixture that included both C. lectularius and C. hemipterus) were collected from across Australian and subsequently colonized for laboratory-based insecticide resistance testing. To screen for resistance, bed bugs were exposed topically to a discriminating dose of 2.5 g/L deltamethrin and, separately, 0.1 g/L of imidacloprid, applied at a rate of 1 μL/bug. Results indicated a broad spread in the frequency of resistance against deltamethrin in C. lectularius. Mortality was predominantly high with C. lectularius against imidacloprid at ≥95%, except for several recently collected strains that returned between 70%-85%, indicating that a degree of tolerance may be developing in select strains. Three of four C. hemipterus strains returned mortality values at or below 10%, with the remainder recording 75% mortality, thereby indicating pyrethroid resistance is similarly advanced in this species. Normal susceptibility (≥95% mortality) was otherwise evident in all four C. hemipterus strains to imidacloprid. These findings complement concurrent research, which indicates variable patterns of resistance mechanisms are present across the Australia and around the world. The results have profound implications for product manufacturers and registration authorities in ensuring that a product is as effective at controlling bed bugs in the field as the laboratory.