Frequencies of the pyrethroid resistance alleles of Vssc1 and CYP6D1 in house flies from the eastern United States

Abstract

House flies were collected from four dairies in Maine, New York, North Carolina, and Florida, where high levels of resistance to permethrin have been documented. Regions of two genes, CYP6D1 and Vssc1, having alleles that confer resistance to permethrin (and other pyrethroids) were analysed from individuals at each collection site. The combinations of resistance alleles for Vssc1 and CYP6D1 were highly variable between each state. The resistance allele CYP6D1v1 was found at a high frequency (0.63-0.91) at all sites. Individuals homozygous susceptible for CYP6D1 were very rare and detected only at the dairy in Maine. In addition to the typical Vssc1 mutation responsible for resistance, kdr (L1014F), we also identified individuals with a L1014H mutation. Although house flies homozygous for the L1014H mutation had a lower level of resistance to permethrin, compared to L1014F, the H1014 resistance allele was frequently detected. No individuals with the super-kdr allele (M918T + L1014F) were detected from the field collections. The intron 3 bp downstream of the kdr mutation was found to be extremely variable, providing an opportunity to reconstruct a phylogeny of Vssc1 alleles. Based on this analysis it appears the kdr-his mutation had multiple evolutionary origins, but that the kdr mutation may have had a single origin. The impacts of these findings on resistance management are discussed.

Sodium channel gene expression associated with pyrethroid resistant house flies and German cockroaches

“…In all cases, the PCR sequence was the sodium channel gene fragment. Interestingly, using the primers designed in our study, we did not detect any introns in this region in both house flies and German cockroaches as previously reported (Dong et al, 1998;Rinkevich et al, 2006). Except in the German cockroach ACY strain, different genotypes for the kdr locus were observed among individuals in the same population of each insect species.…”

Pyrethroid Insecticide Resistance <i>kdr</i> Gene in the House Fly, <i>Musca domestica</i> (Diptera: Muscidae), in the United Arab Emirates

“…Similarly, Rinkevich et al [10] reported that the resistance allele CYP6D1v1 was found at a high frequency (0.63 -0.91) in house fly populations at all sites. In the present study, the maximum frequency (0.8) of the kdr allele was found at Ajman.…”

“…Similarly, Huang et al [11] reported variabiliy in genotypes among house fly populations. Rinkevich et al [10] reported that combinations of pyrethroid insecticide resistance alleles of Vssc1 and CYP6D1 were highly variable between the states from which the house flies were collected. Resistant insects of the genotype kdr/kdr were detected at Abu Dhabi, Dubai, Fujairah, Ajman, and Ras Al-Khaymah.…”

“…At amino acid residue 1014, a mutation of leucine to phenylalanine (L1014F), which is known as the kdr mutation in the para-type sodium channel gene, has been consistently associated with knockdown resistance in house flies [8] [9]. Resistant flies have alleles such as CYP6D1 and Vssc1 that conferred resistance to permethrin and other pyrethroids [10].…”

Dynamics of insecticide resistance alleles in house fly populations from New York and Florida

“…The M918T mutation is not found in the absence of the L1014F mutation (Soderlund and Knipple, 2003) and it appears that the super-kdr allele evolved from the kdr allele (Rinkevich, 2005). There are two additional Vssc1-resistance alleles (L1014H), termed kdr-his1 and kdr-his2, found in the US (Liu and Pridgeon, 2002;Rinkevich et al, 2006). The kdr-his2 allele was found only in house flies collected from a NC dairy in 2002 (Rinkevich et al, 2006).…”