Are Australian field‐collected strains of Cimex lectularius and Cimex hemipterus (Hemiptera: Cimicidae) resistant to deltamethrin and imidacloprid as revealed by topical assay?

Abstract

Resistance profiling on Cimex lectularius and Cimex hemipterus in Australia has previously revealed the existence of resistance to pyrethroid insecticides and that multiple resistant mechanisms exist in field populations. To further investigate insecticide resistance in modern field populations of bed bugs, a program to collect and screen field specimens was initiated. Over 50 bed bug strains (a mixture that included both C. lectularius and C. hemipterus) have been collected from across Australian, with 35 subsequently colonised (31 C. lectularius and 4 C. hemipterus) for laboratory-based insecticide resistance testing. Bed bugs were exposed topically to pyrethroids at a discriminating dose of 2.5 g/L deltamethrin in acetone applied at a rate of 1 μL/bug and, for neonicotinoids, a dose of 0.1 g/L of imidacloprid applied at a rate of 1 μL/bug. Mortality was recorded 24 h post application. Twenty adult bed bugs of mixed sex and age in two replicates of 10 were used for the bioassays, plus controls. Results indicated a broad spread in the frequency of resistance against deltamethrin in C. lectularius, represented by a range of mortality values between 15 and 100%. Mortality was predominantly uniform with C. lectularius against imidacloprid at ≥95%, except for several recently collected strains that returned between 70 and 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 that variable patterns of resistance are present across the country 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. Key wordscommon bed bug, insecticide resistance, tropical bed bug.

High levels of pyrethroid resistance and super-kdr mutations in the populations of tropical bed bug, Cimex hemipterus, in Iran

“…Similar phenomenon in this study, i.e. resistance to insecticides, was found in the field strains of C. hemipterus to different pyrethroids (bifenthrin, cypermethrin, esfenvalerate, and etofenprox) from Thailand [42], DDT and deltamethrin residues from Malaysia [45], a mixture of deltamethrin and imidacloprid from Australia [52], and permethrin and deltamethrin from Sri Lanka [26]. These conditions were also represented in different populations of the common bed bug for pyrethroids from USA [23], permethrin and deltamethrin from Australia [53], allethrin from Sydney [44], imidacloprid and β-cyfluthrin from Malaysia [54,55], several neonicotinoids (imidacloprid, acetamiprid, thiamethoxam, and dinotefuran) from USA [56], bifenthrin from Germany [57], a mixture of deltamethrin and imidacloprid from Australia [53], and bendiocarb from Paris [58].…”

“…These conditions were also represented in different populations of the common bed bug for pyrethroids from USA [23], permethrin and deltamethrin from Australia [53], allethrin from Sydney [44], imidacloprid and β-cyfluthrin from Malaysia [54,55], several neonicotinoids (imidacloprid, acetamiprid, thiamethoxam, and dinotefuran) from USA [56], bifenthrin from Germany [57], a mixture of deltamethrin and imidacloprid from Australia [53], and bendiocarb from Paris [58]. Based on the bioassay results and the findings of previous studies [26,42,45,52], all the bed bug populations in the present study manifested resistance to permethrin. Thus, the reconsideration of control methodologies is of paramount importance in the studied areas.…”

A major 6 Mb superlocus is involved in pyrethroid resistance in the common bed bugCimex lectularius

“…In bed bugs, many reports showed resistance through phenotypic assays to various insecticides (Romero and Anderson, 2016; Lilly et al, 2018; Cáceres et al, 2019). Using knowledge obtained on other insect systems, the association between resistance phenotype and genes has been explored for a few candidate genes, such as VGSC (Zhu et al, 2010).…”

Influences of Exposure Time and Mortality Assessment Interval on Bioassay Results of Insecticide-Resistant Tropical Bed Bugs (Hemiptera: Cimicidae)

“…Insecticide resistance in bed bugs has been evaluated using technical grade insecticides [ 4 , 5 , 6 , 7 ] and commercial insecticide products and formulations [ 8 , 9 , 10 , 11 ]. Bed bugs have been found resistant to several insecticide classes that are commonly incorporated in formulated products, such as pyrethroids [ 11 , 12 , 13 ], neonicotinoids [ 4 , 14 ], organophosphates [ 15 , 16 , 17 ], and pyrroles [ 10 ]. Several bioassay methods have been used in resistance testing.…”