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Differential sensitivity to Bacillus thuringiensis var. Israelensis and temephos in field mosquito populations of Ochlerotatus cataphylla (diptera: Culicidae): Toward resistance?
Author(s) -
Boyer Sébastien,
Tilquin Mathieu,
Ravanel Patrick
Publication year - 2007
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/06-205r.1
Subject(s) - bacillus thuringiensis , biology , larva , organophosphate , population , toxicology , insecticide resistance , pesticide resistance , mosquito control , culex pipiens , veterinary medicine , pesticide , botany , ecology , bacteria , genetics , demography , sociology , malaria , immunology , medicine
In the present study, four populations of the same field mosquito species, Ochlerotatus cataphylla , were sampled over the Rhône‐Alpes region (France), and their respective sensitivity to the organophosphate temephos and the bacterio‐insecticide Bacillus thuringiensis var. israelensis (Bti ) was measured. The results obtained in toxicological tests showed significant differences in the larval sensitivities of the four populations for both insecticides. These differences appeared to be related to the activity of the three main families of detoxifying enzymes: Cytochrome P450 monooxygenases, glutathione‐ S ‐transferases (GSTs), and esterases. All three enzyme families were significantly overexpressed in the less susceptible larval population, and after multiple regressions, GSTs and esterases came out as the most explicative variables of the larval sensitivity. Considering these results and the chemical history of the sites in terms of insecticide treatments, the hypothesis of cross‐effects of insecticides leading to resistance acquisition to Bti in field organisms emerges.