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Different repellents for Aedes aegypti against blood-feeding and oviposition.

Afify A, Horlacher B, Roller J, Galizia CG - PLoS ONE (2014)

Bottom Line: In both behavioral situations we compared the effect to the well-documented repellent N,N-diethyl-meta-toluamide (DEET).MDA, EA, and DEET inhibited Aedes aegypti from flying towards skin odor while BA had no such effect.Conversely, MDA had no effect on oviposition while EA, BA, and DEET deterred oviposition, with the strongest effect observed for BA.

View Article: PubMed Central - PubMed

Affiliation: Neurobiology, University of Konstanz, Konstanz, Germany.

ABSTRACT
Methyl N,N-dimethyl anthranilate (MDA), ethyl anthranilate (EA) and butyl anthranilate (BA) were previously shown to repel Aedes aegypti mosquitoes from landing on human skin. However, the effect of these compounds on the orientation of flying mosquitoes in a choice situation and their effect on mosquito oviposition are not yet known. Here, we used a modified Y-tube olfactometer to test the effect of these compounds on the orientation of Aedes aegypti flying towards skin odor (human fingers), and we tested their effect on Aedes aegypti oviposition choice in a cage assay. In both behavioral situations we compared the effect to the well-documented repellent N,N-diethyl-meta-toluamide (DEET). MDA, EA, and DEET inhibited Aedes aegypti from flying towards skin odor while BA had no such effect. Conversely, MDA had no effect on oviposition while EA, BA, and DEET deterred oviposition, with the strongest effect observed for BA. Thus, we confirm that EA and DEET are generally repellent, while MDA is repellent only in a host-seeking context, and BA is deterrent only in an oviposition context. These compounds appear of potential use in mosquito control programs.

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Preference Index (PI) of MDA, EA, BA, and DEET in experiment 1 and 2.Non-blood fed Ae. aegypti females were repelled by MDA, EA, and DEET while BA did not have an effect on mosquito orientation. A) Pooled preference index from first and second trial in experiment 1 shows a repellent effect for MDA, EA, and DEET (p<0.001, Student t-test, n = 10) and no effect for BA (p = 0.922, Student t-test, n = 10). B) Preference index in experiment 2 shows a repellent effect for MDA, EA, and DEET (p = 0.004, 0.002, and <0.001, respectively, Student t-test, n = 7) and no effect for BA (p = 0.868, Student t-test, n = 7). Number of asterisks indicates the level of significance; p<0.05 (*), and p<0.001 (***).
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pone-0103765-g003: Preference Index (PI) of MDA, EA, BA, and DEET in experiment 1 and 2.Non-blood fed Ae. aegypti females were repelled by MDA, EA, and DEET while BA did not have an effect on mosquito orientation. A) Pooled preference index from first and second trial in experiment 1 shows a repellent effect for MDA, EA, and DEET (p<0.001, Student t-test, n = 10) and no effect for BA (p = 0.922, Student t-test, n = 10). B) Preference index in experiment 2 shows a repellent effect for MDA, EA, and DEET (p = 0.004, 0.002, and <0.001, respectively, Student t-test, n = 7) and no effect for BA (p = 0.868, Student t-test, n = 7). Number of asterisks indicates the level of significance; p<0.05 (*), and p<0.001 (***).

Mentions: In experiment 1, we tested each group of mosquitoes twice to check for side bias. The proportion of mosquitoes choosing MDA, EA, BA, or DEET were not significantly different between right and left chambers (p = 0.440, 0.649, 0.313, and 0.170, respectively, paired t-test, n = 5 each, Fig. 2). We therefore pooled all first and second trials together (n = 10) and tested for repellency of the compounds. MDA, EA, and DEET showed significant repellency with mean PIs significantly lower than that of a neutral 50∶50 distribution between right and left chambers (p<0.001, Student t-test, n = 10, Fig. 3A). On the other hand, the proportion of mosquitoes that chose BA (PI) was not significantly different (p = 0.922, Student t-test, n = 10, Fig. 3A) from 0 (PI of a 50∶50 distribution). In this experiment, the proportion of mosquitoes that made a choice (trapped in either the test or the control chamber) when testing BA was very low (mean = 9.5%) compared with those when testing MDA, EA, and DEET (24.5, 65.5, and 39%, respectively).


Different repellents for Aedes aegypti against blood-feeding and oviposition.

Afify A, Horlacher B, Roller J, Galizia CG - PLoS ONE (2014)

Preference Index (PI) of MDA, EA, BA, and DEET in experiment 1 and 2.Non-blood fed Ae. aegypti females were repelled by MDA, EA, and DEET while BA did not have an effect on mosquito orientation. A) Pooled preference index from first and second trial in experiment 1 shows a repellent effect for MDA, EA, and DEET (p<0.001, Student t-test, n = 10) and no effect for BA (p = 0.922, Student t-test, n = 10). B) Preference index in experiment 2 shows a repellent effect for MDA, EA, and DEET (p = 0.004, 0.002, and <0.001, respectively, Student t-test, n = 7) and no effect for BA (p = 0.868, Student t-test, n = 7). Number of asterisks indicates the level of significance; p<0.05 (*), and p<0.001 (***).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4117642&req=5

pone-0103765-g003: Preference Index (PI) of MDA, EA, BA, and DEET in experiment 1 and 2.Non-blood fed Ae. aegypti females were repelled by MDA, EA, and DEET while BA did not have an effect on mosquito orientation. A) Pooled preference index from first and second trial in experiment 1 shows a repellent effect for MDA, EA, and DEET (p<0.001, Student t-test, n = 10) and no effect for BA (p = 0.922, Student t-test, n = 10). B) Preference index in experiment 2 shows a repellent effect for MDA, EA, and DEET (p = 0.004, 0.002, and <0.001, respectively, Student t-test, n = 7) and no effect for BA (p = 0.868, Student t-test, n = 7). Number of asterisks indicates the level of significance; p<0.05 (*), and p<0.001 (***).
Mentions: In experiment 1, we tested each group of mosquitoes twice to check for side bias. The proportion of mosquitoes choosing MDA, EA, BA, or DEET were not significantly different between right and left chambers (p = 0.440, 0.649, 0.313, and 0.170, respectively, paired t-test, n = 5 each, Fig. 2). We therefore pooled all first and second trials together (n = 10) and tested for repellency of the compounds. MDA, EA, and DEET showed significant repellency with mean PIs significantly lower than that of a neutral 50∶50 distribution between right and left chambers (p<0.001, Student t-test, n = 10, Fig. 3A). On the other hand, the proportion of mosquitoes that chose BA (PI) was not significantly different (p = 0.922, Student t-test, n = 10, Fig. 3A) from 0 (PI of a 50∶50 distribution). In this experiment, the proportion of mosquitoes that made a choice (trapped in either the test or the control chamber) when testing BA was very low (mean = 9.5%) compared with those when testing MDA, EA, and DEET (24.5, 65.5, and 39%, respectively).

Bottom Line: In both behavioral situations we compared the effect to the well-documented repellent N,N-diethyl-meta-toluamide (DEET).MDA, EA, and DEET inhibited Aedes aegypti from flying towards skin odor while BA had no such effect.Conversely, MDA had no effect on oviposition while EA, BA, and DEET deterred oviposition, with the strongest effect observed for BA.

View Article: PubMed Central - PubMed

Affiliation: Neurobiology, University of Konstanz, Konstanz, Germany.

ABSTRACT
Methyl N,N-dimethyl anthranilate (MDA), ethyl anthranilate (EA) and butyl anthranilate (BA) were previously shown to repel Aedes aegypti mosquitoes from landing on human skin. However, the effect of these compounds on the orientation of flying mosquitoes in a choice situation and their effect on mosquito oviposition are not yet known. Here, we used a modified Y-tube olfactometer to test the effect of these compounds on the orientation of Aedes aegypti flying towards skin odor (human fingers), and we tested their effect on Aedes aegypti oviposition choice in a cage assay. In both behavioral situations we compared the effect to the well-documented repellent N,N-diethyl-meta-toluamide (DEET). MDA, EA, and DEET inhibited Aedes aegypti from flying towards skin odor while BA had no such effect. Conversely, MDA had no effect on oviposition while EA, BA, and DEET deterred oviposition, with the strongest effect observed for BA. Thus, we confirm that EA and DEET are generally repellent, while MDA is repellent only in a host-seeking context, and BA is deterrent only in an oviposition context. These compounds appear of potential use in mosquito control programs.

Show MeSH