Volume 81, October 2015, Pages 137–144
Highlights
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- The efficacy and action mechanism of repellents remain unknown for most insects.
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- We tested commercial and novel molecules on Rhodnius prolixus using three bioassays.
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- Repellents repel R. prolixus by themselves, showing that bugs can smell them.
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- The performance of repellents on bugs differs from that on mosquitoes.
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- We present simple bioassays for testing repellents against Chagas disease vectors.
Abstract
Insect
repellents are known since many decades ago and constitute a major tool
for personal protection against the biting of mosquitoes. Despite their
wide use, the understanding of why and how repellents repel is
relatively recent. In particular, the question about to what extent
insects other than mosquitoes are repulsed by repellents remains open.
We developed a series of bioassays aimed to test the performance of well
established as well as potential repellent molecules on the Chagas
disease vector Rhodnius prolixus. Besides testing their ability
to prevent biting, we tested the way in which they act, i.e., by
obstructing the detection of attractive odours or by themselves. By
using three different experimental protocols (host-biting, open-loop
orientation to odours and heat-triggered proboscis extension response)
we show that DEET repels bugs both in the presence and in the absence of
host-associated odours but only at the highest quantities tested.
Piperidine was effective with or without a host and icaridine only
repelled in the absence of a living host. Three other molecules recently
proposed as potential repellents due to their affinity to the Ir40a+
receptor (which is also activated by DEET) did not evoke significant
repellency. Our work provides novel experimental tools and sheds light
on the mechanism behind repellency in haematophagous bugs.
Graphical abstract
Keywords
- Vector insects;
- DEET;
- Icaridine;
- Triatomines;
- Ir40a+
Copyright © 2015 Elsevier Ltd. All rights reserved.
