Abstracts (first author)
Rapid evolution of insecticide resistance genes in mosquito populations: a quantitative approach
How adaptation appears and is later refined by natural selection has been the object of intense theoretical work. However, the testing of these theories is limited by our ability to estimate the strength of natural selection in nature. Selection by insecticide treatments of the Ester resistance gene in populations of the mosquito Culex pipiens in Montpellier area (southern France) is a contemporary example of rapid evolution of an adaptation to environmental changes in natural populations. We observed in twenty years, the emergence and replacement of three resistance alleles at the Ester locus due to the selection pressure of insecticide uses. With continuous sampling for >40 years on a 50 km transect corresponding to a gradient of insecticides treatment, we were able to follow the dynamics of these different alleles in natural populations. Using a population genetics model taking into account environmental variables, we were able to estimate the intensity of the selection pressure, as well as many parameters (genetic and environmental) affecting the dynamics of these alleles. In addition, we were able to analyze the evolution of allele frequencies under various environmental conditions. For example the prohibition by the European instances of OP’s insecticides in 2007 was a full-scale test of the quality of our predictions. I will present this work, which links ecology and evolution, through the integration of environmental data into a genetic model, to analyze the dynamics of adaptive alleles in natural populations. We quantified the selection and environmental parameters conditioning resistance genes dynamic and showed that the relationship between environmental factors and allele dynamics in natural populations is not straightforward.