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Unexpected effects of low doses of a neonicotinoid insecticide on behavioral responses to sex pheromone in a pest insect.

Rabhi KK, Esancy K, Voisin A, Crespin L, Le Corre J, Tricoire-Leignel H, Anton S, Gadenne C - PLoS ONE (2014)

Bottom Line: We show that low doses of clothianidin induce a biphasic effect on pheromone-guided behavior.Surprisingly, we found a hormetic-like effect, improving orientation behavior at the LD20 dose corresponding to 10 ng clothianidin.No clothianidin effect was observed on behavioral responses to plant odor.

View Article: PubMed Central - PubMed

Affiliation: INRA/Université d'Angers, Neuroéthologie-RCIM, UPRES-EA 2647 USC INRA 1330, SFR 4207 QUASAV, 42, rue Georges Morel, F-49071 Beaucouzé, France.

ABSTRACT
In moths, which include many agricultural pest species, males are attracted by female-emitted sex pheromones. Although integrated pest management strategies are increasingly developed, most insect pest treatments rely on widespread use of neurotoxic chemicals, including neonicotinoid insecticides. Residual accumulation of low concentrations of these insecticides in the environment is known to be harmful to beneficial insects such as honey bees. This environmental stress probably acts as an "info-disruptor" by modifying the chemical communication system, and therefore decreases chances of reproduction in target insects that largely rely on olfactory communication. However, low doses of pollutants could on the contrary induce adaptive processes in the olfactory pathway, thus enhancing reproduction. Here we tested the effects of acute oral treatments with different low doses of the neonicotinoid clothianidin on the behavioral responses to sex pheromone in the moth Agrotis ipsilon using wind tunnel experiments. We show that low doses of clothianidin induce a biphasic effect on pheromone-guided behavior. Surprisingly, we found a hormetic-like effect, improving orientation behavior at the LD20 dose corresponding to 10 ng clothianidin. On the contrary, a negative effect, disturbing orientation behavior, was elicited by a treatment with a dose below the LD0 dose corresponding to 0.25 ng clothianidin. No clothianidin effect was observed on behavioral responses to plant odor. Our results indicate that risk assessment has to include unexpected effects of residues on the life history traits of pest insects, which could then lead to their adaptation to environmental stress.

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Related in: MedlinePlus

Toxicity of acute oral clothianidin treatment for adult A. ipsilon males.Four-day-old males were intoxicated with a range of concentrations of clothianidin (0.1 ng–2.5 µg/moth). The number of surviving males was recorded 24 h and 48 h after intoxication. The median lethal dose (LD50) was determined at 69±0.04 ng and 29±0.07 ng/moth 24 h and 48 h after treatment respectively. N = 50 for each dose.
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pone-0114411-g001: Toxicity of acute oral clothianidin treatment for adult A. ipsilon males.Four-day-old males were intoxicated with a range of concentrations of clothianidin (0.1 ng–2.5 µg/moth). The number of surviving males was recorded 24 h and 48 h after intoxication. The median lethal dose (LD50) was determined at 69±0.04 ng and 29±0.07 ng/moth 24 h and 48 h after treatment respectively. N = 50 for each dose.

Mentions: Four day-old sexually mature males were fed individually with clothianidin or control solutions (solvent dimethyl sulfoxide [DMSO] or sucrose) and mortality was recorded 24 h and 48 h later. For most males, the solution containing clothianidin was quickly ingested (a few seconds). No mortality was observed in control groups (n = 50 for sucrose and solvent groups). The theoretical lethal dose 50 (LD50: dose resulting in 50% mortality post-treatment) was determined by dose-response assays ranging from 0.1 ng to 2.5 µg/moth (n = 50 for each dose) (Fig. 1) and was found to be 69±0.04 ng/moth and 29±0.07 ng/moth 24 h and 48 h after treatment, respectively. Before dying, intoxicated insects exhibited trembling and incapacity to move.


Unexpected effects of low doses of a neonicotinoid insecticide on behavioral responses to sex pheromone in a pest insect.

Rabhi KK, Esancy K, Voisin A, Crespin L, Le Corre J, Tricoire-Leignel H, Anton S, Gadenne C - PLoS ONE (2014)

Toxicity of acute oral clothianidin treatment for adult A. ipsilon males.Four-day-old males were intoxicated with a range of concentrations of clothianidin (0.1 ng–2.5 µg/moth). The number of surviving males was recorded 24 h and 48 h after intoxication. The median lethal dose (LD50) was determined at 69±0.04 ng and 29±0.07 ng/moth 24 h and 48 h after treatment respectively. N = 50 for each dose.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4269385&req=5

pone-0114411-g001: Toxicity of acute oral clothianidin treatment for adult A. ipsilon males.Four-day-old males were intoxicated with a range of concentrations of clothianidin (0.1 ng–2.5 µg/moth). The number of surviving males was recorded 24 h and 48 h after intoxication. The median lethal dose (LD50) was determined at 69±0.04 ng and 29±0.07 ng/moth 24 h and 48 h after treatment respectively. N = 50 for each dose.
Mentions: Four day-old sexually mature males were fed individually with clothianidin or control solutions (solvent dimethyl sulfoxide [DMSO] or sucrose) and mortality was recorded 24 h and 48 h later. For most males, the solution containing clothianidin was quickly ingested (a few seconds). No mortality was observed in control groups (n = 50 for sucrose and solvent groups). The theoretical lethal dose 50 (LD50: dose resulting in 50% mortality post-treatment) was determined by dose-response assays ranging from 0.1 ng to 2.5 µg/moth (n = 50 for each dose) (Fig. 1) and was found to be 69±0.04 ng/moth and 29±0.07 ng/moth 24 h and 48 h after treatment, respectively. Before dying, intoxicated insects exhibited trembling and incapacity to move.

Bottom Line: We show that low doses of clothianidin induce a biphasic effect on pheromone-guided behavior.Surprisingly, we found a hormetic-like effect, improving orientation behavior at the LD20 dose corresponding to 10 ng clothianidin.No clothianidin effect was observed on behavioral responses to plant odor.

View Article: PubMed Central - PubMed

Affiliation: INRA/Université d'Angers, Neuroéthologie-RCIM, UPRES-EA 2647 USC INRA 1330, SFR 4207 QUASAV, 42, rue Georges Morel, F-49071 Beaucouzé, France.

ABSTRACT
In moths, which include many agricultural pest species, males are attracted by female-emitted sex pheromones. Although integrated pest management strategies are increasingly developed, most insect pest treatments rely on widespread use of neurotoxic chemicals, including neonicotinoid insecticides. Residual accumulation of low concentrations of these insecticides in the environment is known to be harmful to beneficial insects such as honey bees. This environmental stress probably acts as an "info-disruptor" by modifying the chemical communication system, and therefore decreases chances of reproduction in target insects that largely rely on olfactory communication. However, low doses of pollutants could on the contrary induce adaptive processes in the olfactory pathway, thus enhancing reproduction. Here we tested the effects of acute oral treatments with different low doses of the neonicotinoid clothianidin on the behavioral responses to sex pheromone in the moth Agrotis ipsilon using wind tunnel experiments. We show that low doses of clothianidin induce a biphasic effect on pheromone-guided behavior. Surprisingly, we found a hormetic-like effect, improving orientation behavior at the LD20 dose corresponding to 10 ng clothianidin. On the contrary, a negative effect, disturbing orientation behavior, was elicited by a treatment with a dose below the LD0 dose corresponding to 0.25 ng clothianidin. No clothianidin effect was observed on behavioral responses to plant odor. Our results indicate that risk assessment has to include unexpected effects of residues on the life history traits of pest insects, which could then lead to their adaptation to environmental stress.

Show MeSH
Related in: MedlinePlus