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Acquisition d’une tolérance aux insecticides en vergers de pommiers et ses conséquences chez une espèce auxiliaire, le forficule Forficula auricularia L

Abstract : In the European context of reducing pesticide use, knowledge of the effects of insecticides on natural enemies is an innovative and promising approach for the development of new Integrated Pest Management (IPM) program. European earwigs Forficula auricularia (Linnaeus) are considered as efficient predators in apple orchards and contribute to the biological control of aphids, leaf rollers and psyllids.Earwigs were sampled in apple orchards in Provence, (South-Eastern France), managed under contrasting strategies: organic, integrated pest management (IPM), conventional, or untreated orchards. Our study underlines the differences in metabolic pathway responses in F. auricularia populations influenced by their historic management strategies. In particular, we have shown that earwigs collected in conventional orchard exhibited lower mortality and higher enzyme activities (glutathion-S-transferases and carboxylesterases) involved in detoxification, compare to organic orchard. A decrease in sensitivity of the acetylcholinesterase (the molecular target of OP insecticides, involved in the nervous system functioning) was also observed in earwigs pre-exposed in the conventional orchard with higher sensitivity of AChE in male compared to female earwigs. We have investigated the induction of Hsp70s as an efficient defense mechanism, which could play an important role in tolerance to insecticide. Our results underlined the differences previously observed depending on management strategy and for a considered orchard, depending on earwig sex.It is well known that insecticide tolerance can be associated with fitness costs. That is why energetic reserves (glycogen, lipids and proteins) and morphological traits have been quantified on earwigs from orchards with different management practices. F. auricularia from conventional orchards were smaller than the other earwigs. Moreover, we have shown that the amount of energetic reserves depended on insecticide use and on the period of sampling. The high glycogen content observed in females collected in conventional orchards, 2 months after the end of treatments, supports a reallocation of reserves to the reproduction.This work brought to light the emergence of resistance to insecticides of the natural enemy F. auricularia, exposed to pesticides in conventional apple orchard.
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  • HAL Id : tel-02880079, version 1
  • PRODINRA : 496122

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Adrien Le Navenant. Acquisition d’une tolérance aux insecticides en vergers de pommiers et ses conséquences chez une espèce auxiliaire, le forficule Forficula auricularia L. Sciences agricoles. Université d'Avignon, 2019. Français. ⟨NNT : 2019AVIG0354⟩. ⟨tel-02880079⟩

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