Adverse effects of Bt bioinsecticides on Drosophila development and fitness

Abstract

Biopesticides are expected to replace chemical pesticides for many applications and are therefore increasingly used against insect pests. Among the bioinsecticides, those made of the bacterium Bacillus thuringiensis (Bt) represent 90% of total sales worldwide. Bt is a Gram-positive bacterium that produces during its sporulation different combinations of toxins named Cry. Among the various strains of Bt, some have been selected for their specificity of action against pests. They respect, in terms of acute toxicity, the other species of the ecosystem. Bt kurstaki (Btk), the most widely used bioinsecticides, is used in France to fight against pine and oak processionary moth as well as in organic farming. Because of both their increased use and environmental dispersion, Bt bioinsecticides will be more and more present in the air, water and food, three potential sources of contamination for animals. Unfortunately, the long-term effects of a chronic exposure on non-target organisms are still unknown.

Therefore using the non-target model organism Drosophila melanogaster, we assessed the potential adverse effects due to the ingestion of a Btk-contaminated food on both the development and fitness traits. I will present you the last results obtained in the team by M. Pasco.