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How to Make Evolution-Proof Insecticides for Malaria Control

  • Andrew F Read mail,

    To whom correspondence should be addressed. E-mail:

  • Penelope A Lynch,
  • Matthew B Thomas
  • Published: April 07, 2009
  • DOI: 10.1371/journal.pbio.1000058

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Lowering concentrations is not dangerous – if it makes insecticides late-life acting

Posted by plosbiology on 07 May 2009 at 22:29 GMT

Author: Andrew Read
Position: Professor of Biology and Entomology
Institution: Penn State
Additional Authors: Penelope Lynch, Matthew Thomas
Submitted Date: April 21, 2009
Published Date: April 27, 2009
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

We agree our suggestion deserves further exploration, but not for the reason Briet gives. Whatever form of resistance exists or arises in a population, the smaller the impact of an insecticide on mosquito fitness, the lower the selection pressure in favor of that resistant form. As we show in our paper, reducing the impact of insecticides on younger age classes is a powerful way of minimizing their fitness impact and hence evolution-proofing insecticides.

Put another way: even if alleles conferring ‘partial’ resistance to currently recommended concentrations confer ‘full’ resistance against lower concentrations, the insecticides still impose only very weak selection on those alleles so long as they impact only on the survival and reproduction of the older (dangerous) mosquitoes.

So the open question, and one we are working on, is whether any existing insecticides can in practice be turned into late-life acting public health insecticides by lowering the concentrations at which they are used, or by other changes in formulation/delivery. If yes, they can be 'evolution-proofed'. If no, there are not any easy fixes, and we need new chemistry or biopesticides, as outlined in the paper.

No competing interests declared.