Insecticide resistance status of United States populations of Aedes albopictus and mechanisms involved

PLoS One. 2014 Jul 11;9(7):e101992. doi: 10.1371/journal.pone.0101992. eCollection 2014.

Abstract

Aedes albopictus (Skuse) is an invasive mosquito that has become an important vector of chikungunya and dengue viruses. Immature Ae. albopictus thrive in backyard household containers that require treatment with larvicides and when adult populations reach pest levels or disease transmission is ongoing, adulticiding is often required. To assess the feasibility of control of USA populations, we tested the susceptibility of Ae. albopictus to chemicals representing the main insecticide classes with different modes of action: organochlorines, organophosphates, carbamates, pyrethroids, insect growth regulators (IGR), naturalytes, and biolarvicides. We characterized a susceptible reference strain of Ae. albopictus, ATM95, and tested the susceptibility of eight USA populations to five adulticides and six larvicides. We found that USA populations are broadly susceptible to currently available larvicides and adulticides. Unexpectedly, however, we found significant resistance to dichlorodiphenyltrichloroethane (DDT) in two Florida populations and in a New Jersey population. We also found resistance to malathion, an organophosphate, in Florida and New Jersey and reduced susceptibility to the IGRs pyriproxyfen and methoprene. All populations tested were fully susceptible to pyrethroids. Biochemical assays revealed a significant up-regulation of GSTs in DDT-resistant populations in both larval and adult stages. Also, β-esterases were up-regulated in the populations with suspected resistance to malathion. Of note, we identified a previously unknown amino acid polymorphism (Phe → Leu) in domain III of the VGSC, in a location known to be associated with pyrethroid resistance in another container-inhabiting mosquito, Aedes aegypti L. The observed DDT resistance in populations from Florida may indicate multiple introductions of this species into the USA, possibly from tropical populations. In addition, the mechanisms underlying DDT resistance often result in pyrethroid resistance, which would undermine a remaining tool for the control of Ae. albopictus. Continued monitoring of the insecticide resistance status of this species is imperative.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aedes / drug effects*
  • Aedes / genetics*
  • Animals
  • DDT / pharmacology
  • Insect Proteins / genetics
  • Insecticide Resistance / genetics
  • Insecticide Resistance / physiology
  • Insecticides / pharmacology*

Substances

  • Insect Proteins
  • Insecticides
  • DDT

Grants and funding

This work was funded by a cooperative Agreement between the United States Department of Agriculture (USDA) and Rutgers University (USDA-ARS-58-6615-8-105) entitled "Area-wide Pest Management Program for the Asian Tiger Mosquito in New Jersey." The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.