Multiple Origins of kdr-type Resistance in the House Fly, Musca domestica

Frank D Rinkevich,Sarah A Harris,Xinghui Qiu,Cathy Su,Cheryl A Leichter,Vatan Taskin,Jeffrey G Scott,Seán G Brady,Shannon M Hedtke,John Vontas

doi:10.1371/journal.pone.0052761

Abstract

Insecticide resistance is a model phenotype that can be used to investigate evolutionary processes underlying the spread of alleles across a global landscape, while offering valuable insights into solving the problems that resistant pests present to human health and agriculture. Pyrethroids are one of the most widely used classes of insecticides world-wide and they exert their toxic effects through interactions with the voltage-sensitive sodium channel (Vssc). Specific mutations in Vssc (kdr, kdr-his and super-kdr) are known to cause resistance to pyrethroid insecticides in house flies. In order to determine the number of evolutionary origins of kdr, kdr-his and super-kdr, we sequenced a region of Vssc from house flies collected in the USA, Turkey and China. Our phylogenetic analysis of Vssc unequivocally supports the hypothesis of multiple independent origins of kdr, super-kdr and kdr-his on an unprecedented geographic scale. The implications of these evolutionary processes on pest management are discussed.

Highlights

Insecticide resistance presents a useful phenotypic trait for studies of evolution because the selective agent is known, the force of selection is strong, and the mutations conferring resistance have often been identified
If we make the reasonable assumption that susceptibility is the ancestral condition, there have been at least two independent origins of kdr
M981T mutation has been found without the L1014F mutation in Aphis gossypii [31] and Tetranychus evansi [32]

Summary

Introduction

Insecticide resistance presents a useful phenotypic trait for studies of evolution because the selective agent is known, the force of selection is strong, and the mutations conferring resistance have often been identified. The evolution of resistance constrains our abilities to control pest species, resulting in significant economic and health problems. In naıve (i.e., susceptible) populations resistance alleles are rare, with a frequency of 1022 to 10213 [1,2]. If the resistance allele is completely recessive, the resistant phenotype will be even rarer. The frequency of resistance alleles depends on the strength of selection for resistance, the fitness cost of resistance alleles in the absence of insecticide, the initial frequency of resistance alleles, and the likelihood of gene flow among populations [1,3,4]. Information about the maintenance and spread of these alleles can improve predictive power for the evolutionary outcome of a particular insecticide regime

Methods

Results

Conclusion