Investigation of mutations associated with pyrethroid resistance in populations of the New World Screwworm fly, Cochliomyia hominivorax (Diptera: Calliphoridae)

Abstract

ABSTRACT. Cochliomyia hominivorax larvae are known for their parasitic habit in living vertebrates, causing considerable economic losses to livestock industry. This ectoparasite has been controlled mainly by applying insecticides, but this method usually results in the selection of resistant individuals. The resistance mechanism known as knockdown resistance (kdr) is a generic term for amino acid substitutions in the sodium channel associated with pyrethroid resistance, and substitutions in residue 251 of the carboxylesterase E3 have been associated with organophosphate and pyrethroid hydrolysis. We looked for L1014F kdr and W251S mutations in the sodium channel and E3 genes, respectively, in C. hominivorax populations. Ten populations obtained from its current distribution were investigated using the polymerase chain reaction-restriction fragment length polymorphism technique. No mutant individuals were found for the kdr mutation. However, the W251S mutation was found in all populations investigated. Results from This correlation was not significant at the highest concentration tested (P = 0.221). We suggest that the W251S mutation in the C. hominivorax carboxylesterase E3 is also associated with pyrethroid hydrolysis. This information may contribute to the elaboration of improved management programs for this ectoparasite.

Deep sequencing of New World screw-worm transcripts to discover genes involved in insecticide resistance

“…Molecular studies in this species focused on the characterization of molecular markers in the mitochondrial [7] and nuclear genomes [8,9], their utilization in population genetic studies [10-13] and the characterization of genes and substitutions involved in insecticide resistance [4,14,15]. In a recent study, one substitution was found in the acetylcholinesterase gene (AChE), whose product is the target of OP, but with a very low frequency in several NWS populations [16].…”

“…In a recent study, one substitution was found in the acetylcholinesterase gene (AChE), whose product is the target of OP, but with a very low frequency in several NWS populations [16]. No substitutions were found in the sodium channel gene, target of pyrethroids [15]. In contrast, substitutions in the carboxylesterase E3 gene with very high frequencies were found in several NWS populations surveyed [14-16].…”

Genetic Structure and Demographic History of New World Screwworm Across Its Current Geographic Range

“…The wide range of insecticides used to control pests can cause problems, such as environmental contamination (see Porretta et al 2007) and the selection of insecticide resistant strains (Cassida andGary 1998, Hemingway andRanson 2000). In the screwworm, Carvalho et al (2009) and Silva and Azeredo-Espin (2009) found mutations that are correlated with insecticide resistance. Thus, the necessity to reduce the use of chemicals and adopt control programs with enhanced speciÞcity for the target species, on the appropriate geographic scale, has been highlighted as a more suitable alternative (Kongan 1998, Porretta et al 2007.…”

Acetylcholinesterase cDNA sequencing and identification of mutations associated with organophosphate resistance in Cochliomyia hominivorax (Diptera: Calliphoridae)

“…Absence of mutant alleles (D137) in Colombia, Venezuela and Cuba could be due to low OP pressure in these localities or associated with a historical event in which emergence of Amazon forest divided NWS into two geographical populations, restricting gene flow (Fresia PC, personal communication). A recent investigation of the W251S mutation in the NWS E3 gene, involved in dimethyl-OP and pyrethroid resistance, showed a considerable frequency of this mutation in most of the populations analyzed (Silva and Azeredo-Espin, 2009). Alterations in the frequencies of both mutations in the E3 gene seem to be associated with the use of insecticides for NWS control, as shown in Uruguay (Carvalho et al, 2010).…”

“…Although the Sterile Insect Technique (SIT) was successful for NWS eradication in North and Central America (Galvin and Wyss, 1996), throughout its current geographical distribution the control of this species has relied on the application of chemical insecticides, which normally leads to the selection of resistant individuals. Although there are few reports regarding resistance in NWS (Veríssimo, 2003;Coronado and Kowalski, 2009;Robinson et al, 2009), mutations in the carboxylesterase E3 gene are shown to involve a general form of OP resistance in Lucilia cuprina (Newcomb et al, 1997) and Musca domestica (Claudianos et al, 1999) and have been described in NWS (Carvalho et al, 2006(Carvalho et al, , 2009Silva and Azeredo-Espin, 2009), indicating a putative selective pressure by OP compounds.…”