Biology subjects

Babin, A.

Publications and source records attributed to Babin, A..

3 recordsLinked to original sources

bioRxiv2023

Bacillus thuringiensis bioinsecticide influences Drosophila oviposition decision

Behavioural avoidance has obvious benefits for animals facing environmental stressors such as pathogen-contaminated foods. Most current bioinsecticides are based on the environmental and opportunistic bacterium Bacillus thuringiensis (Bt) that kills targeted insect pests upon ingestion. While food and oviposition avoidance of Bt bioinsecticide by targeted insect species was reported, this remained to be addressed in non-target organisms, especially those affected by chronic exposure to Bt bioinsecticide such as Drosophila species. Here, using a two-choice oviposition test, we showed that female flies of three Drosophila species (four strains of D. melanogaster, D. busckii and D. suzukii) avoided laying eggs in the presence of Bt var. kurstaki bioinsecticide, with potential benefits for the offspring and females fitness. Avoidance occurred rapidly, regardless of the fraction of the bioinsecticide suspension (spores and toxin crystals versus soluble toxins/components) and independently of the female motivation for egg laying. Our results suggest that, in addition to recent findings of developmental and physiological alterations upon chronic exposure of non-target Drosophila, this bioinsecticide may have greater ecological implications in the field for the Drosophila community and their associated natural enemies than previously thought.

evolutionary biology↗

bioRxiv2020

Bacillus thuringiensis var. kurstaki bioinsecticide induces growth defects and developmental delay of the non-target organism Drosophila melanogaster by disturbing homeostasis of the larval intestine

Bioinsecticides made from the bacterium Bacillus thuringiensis (Bt) are the best-selling bioinsecticide worldwide. Among Bt bioinsecticides, those based on the strain Bt var. kurstaki (Btk) are widely used in farming to specifically control pest lepidopteran larvae. Although there is much evidence of the lack of acute lethality of Btk products for non-target animals, only scarce data are available on their potential non-lethal developmental adverse effects. Using doses that could be reached in the field upon sprayings, we have shown that Btk products impair growth and developmental time of the non-target dipteran Drosophila melanogaster. These effects are mediated by the synergy between Btk bacteria and Btk insecticidal toxins, which induces a significant apoptosis of larval enterocytes, resulting in a decreased intestinal capacity to digest proteins. The harmful effects can be mitigated by a protein-rich diet or by adding the probiotic bacterium Lactobacillus plantarum into the food. Finally, we showed that the larval midgut maintain its integrity upon Btk aggression thanks to both the flattening of surviving enterocytes and the generation of new immature cells arising from the adult midgut precursor cells.

physiology↗

bioRxiv2019

Adverse effects of Bacillus thuringiensis bioinsecticide on non-target Drosophila species

Biopesticides based on Bacillus thuringiensis (Bt) spores and toxins are alternate pest management solutions widely used to control insect pests. Their increasing use could lead to accumulation in the environment, hence leading to chronic exposure of non-target organisms. Here, we tested for potential non-intentional side-effects of chronic exposure to Bt biopesticide on larvae of non-target Drosophila species present in Bt-treated areas. Doses up to those recommended for field application (106 CFU/g of fly medium) had no effect on the fly development, whereas doses 10 to 100-fold higher (107-108 CFU/g) increased developmental time and decreased adult emergence rates in a dose-dependent manner and with varying effect amplitudes for all the species and strains tested. For all them, all larvae died before pupation at the highest dose tested (109 CFU/g). Focusing on D. melanogaster, delayed development and reduced emergence resulted from stage-dependent larval mortality, and fitness-related traits of adult flies emerging from surviving Bt biopesticide exposure were moderately increased. The effects of Bt biopesticide seemed to result from the spores/cleaved toxins synergy, and possibly additives. While recommended doses had no effect on non-target Drosophila species, misuse or local accumulation of Bt bioinsecticides in the environment could have non-intentional side-effects on fly populations with potential implications for their associated communities.

ecology↗