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Background  The tropical bed bug,  Cimex hemipterus , is an important ectoparasite causing various health problems. This species is mainly confined to tropical regions; however, insecticide resistance, global warming, and globalization have changed its distribution map. Molecular information on pyrethroid resistance, which is essential for the development of control programs, is unknown for  C. hemipterus  in expanded areas. The present study was designed to determine the permethrin resistance status, characterize the pyrethroid receptor sites in voltage-gated sodium channel ( vgsc ) gene, and identify the resistance-related mutations in the populations of tropical bed bug in Iran.    Methods  Live bed bugs were collected, and adults of  C. hemipterus  were selected for bioassay and molecular surveys. Bioassay was performed by tarsal contact with permethrin 0.75% in mixed-sex of samples. Conventional and quantitative TaqMan and SYBR Green real-time PCR assays were conducted to characterize the  vgsc  gene and genotypes of studied populations.    Results  In the bioassay tests, the mortality rates were in the range of 30.7–38.7% and 56.2–77.4% in 24 and 48 h, respectively. The knockdown rates of studied populations were in the range of 32.2–46.6% and 61.5–83.8% in the first and second days, respectively. The KT 50  and KT 90  values in the  Cimex lectularius  Kh1 strain were presented as 5.39 and 15.55 h, respectively. These values in the selected populations of  C. hemipterus  varied from 27.9 to 29.5 and from 82.8 to 104.4 h, respectively. Knockdown time ratios (KR 50  and KR 90 ) in these populations varied from 5.17 to 6.17-fold compared with those of the  C. lectularius  Kh1 strain. Fragments of  vgsc  gene with 355 bp and 812 bp were amplified. Analysis of sequences revealed the A468T substitution,  kdr -associated D953G, and  super-kdr  M918I and L1014F mutations in all populations.    Conclusions  The specific/sensitive, safe, and rapid diagnostic assays developed in this study are recommended for detection of  kdr/super - kdr  mutations and frequency of mutant alleles. The presence of  super-kdr  mutations and high resistance to permethrin in all the populations necessitate the reconsideration of control approaches against  C. hemipterus .    Graphical Abstract

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