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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

Effect of the 10-ng and 0.25-ng low doses of clothianidin on oriented responses (A) and general flight activity (B) of A. ipsilon males in presence of a linden flower extract.Responses to the linden flower extract were not significantly different between clothianidin- and DMSO-treated males for both 0.25 ng and 10 ng clothianidin. N>50 for all groups, G-test, P<0.05.
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pone-0114411-g004: Effect of the 10-ng and 0.25-ng low doses of clothianidin on oriented responses (A) and general flight activity (B) of A. ipsilon males in presence of a linden flower extract.Responses to the linden flower extract were not significantly different between clothianidin- and DMSO-treated males for both 0.25 ng and 10 ng clothianidin. N>50 for all groups, G-test, P<0.05.

Mentions: We also tested the effect of low doses of clothianidin on the responses of at least 50 intoxicated males/dose to a linden flower extract (see Methods for details). For this, we selected the two clothianidin doses which induced the observed positive (10 ng) and negative (0.25 ng) effects on sex pheromone responses. The general flight activity and the oriented responses towards the linden flower extract were not statistically different between intoxicated and control males (10 ng/moth: G = 0.56, df = 1, P = 0.46; 0.25 ng/moth: G = 0.69, df = 1, P = 0.4) (Fig. 4).


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)

Effect of the 10-ng and 0.25-ng low doses of clothianidin on oriented responses (A) and general flight activity (B) of A. ipsilon males in presence of a linden flower extract.Responses to the linden flower extract were not significantly different between clothianidin- and DMSO-treated males for both 0.25 ng and 10 ng clothianidin. N>50 for all groups, G-test, P<0.05.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0114411-g004: Effect of the 10-ng and 0.25-ng low doses of clothianidin on oriented responses (A) and general flight activity (B) of A. ipsilon males in presence of a linden flower extract.Responses to the linden flower extract were not significantly different between clothianidin- and DMSO-treated males for both 0.25 ng and 10 ng clothianidin. N>50 for all groups, G-test, P<0.05.
Mentions: We also tested the effect of low doses of clothianidin on the responses of at least 50 intoxicated males/dose to a linden flower extract (see Methods for details). For this, we selected the two clothianidin doses which induced the observed positive (10 ng) and negative (0.25 ng) effects on sex pheromone responses. The general flight activity and the oriented responses towards the linden flower extract were not statistically different between intoxicated and control males (10 ng/moth: G = 0.56, df = 1, P = 0.46; 0.25 ng/moth: G = 0.69, df = 1, P = 0.4) (Fig. 4).

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