Time-to-death approach to reveal chronic and cumulative toxicity of a fungicide for honeybees not revealed with the standard ten-day test


  • Simon-Delso, N. , San Martin, G. , Bruneau, E. & Hautier, L. (2018). Time-to-death approach to reveal chronic and cumulative toxicity of a fungicide for honeybees not revealed with the standard ten-day test. Scientific Reports, 8: (1), 7241.
Type Journal Article
Year 2018
Title Time-to-death approach to reveal chronic and cumulative toxicity of a fungicide for honeybees not revealed with the standard ten-day test
Journal Scientific Reports
Volume 8
Issue 1
Pages 7241
Abstract Synthetic fungicides are pesticides widely used in agriculture to control phytopathogenic fungi. The systemicity, persistency and intense application of some of these fungicides, such as boscalid, leads to long periods of exposure for honeybees via contaminated water, pollen and nectar. We exposed adult honeybees in the lab to food contaminated with boscalid for 33 days instead of the standard 10-day test. Most of the toxic effects were observed after 10 days. The median time to death (LT50) ranged from 24.9 days (lowest concentration) to 7.1 days (highest concentration) and was significantly shorter in all cases than with the control (32.0 days). The concentration and dietary doses of boscalid inducing 50% mortality (LC50 and LDD50, respectively) decreased strongly with the time of exposure: LC50?=?14,729 and 1,174?mg/l and LDD50?=?0.318 and 0.0301?mg bee?1 day?1 at days 8 and 25, respectively. We found evidence of reinforced toxicity when exposure is prolonged, but with an unusual pattern: no cumulative toxicity is observed until 17–18 days, when a point of inflexion appears that suggests a reduced capacity of bees to deal with the toxicant. Our results show the importance of time-to-death experiments rather than fixed-duration studies for evaluating chronic toxicity.
Fichier
Lien https://www.nature.com/articles/s41598-018-24746-9
Authors Simon-Delso, N., San Martin, G., Bruneau, E., Hautier, L.

Team