En savoir plus

Vous êtes conviés au séminaire de Léa Tison qui aura lieu le lundi 30 Mai 2022 à partir de 11h dans la salle de réunions SAVE.

Title 

Transfer of pesticide residues in a terrestrial prey-predator system

Abstract

Most biocontrol methods used in agriculture as an alternative to pesticides are based on the consumption of pests by predatory insects, which are themselves consumed by small mammals and birds. However, to date, the use of pesticides is still predominant and both pests and their higher predators in the trophic chain are likely to be contaminated, with pesticide concentrations increasing at each trophic level due to biomagnification. This may result in the lower efficiency of biocontrol methods making the study of the transfer of pesticides between biotic compartments of major interest. This study investigates the transfer of pesticide concentrations in an arthropod predation network which is rarely investigated in terrestrial ecosystems. Although the effect of pesticides on honey bee health is widely studied, nothing is known on the insect predators of the upper trophic chain level that prey on honey bees. Taking advantage of a particular prey-predator system, involving the honey bee and its hornet invasive predator, we study the transfer of pesticides in an insect system. We first developed a method of extraction and quantification of pesticide residues in single hornet individuals by HPLC-MS/MS. We analyzed adults from 24 Asian hornet colonies and found cocktails of different pesticides and a synergist, piperonyl butoxide, at concentrations up to 20 ng/g. We also analyzed pesticides residues, trace metals and metal trackers in honey bees and hornets collected in contrasted agro-ecosystems including vineyards. This study will allow us to understand the bioaccumulation of pesticides in various pollinating or beneficial insects and their predators. More largely, it will also help us to understand the transfer and bioaccumulation of pesticides in terrestrial trophic systems.

Venez nombreux !