Insect repellents are prophylactic tools against a number of vector-borne
diseases. There is growing demand for repellents outperforming DEET in cost
and safety, but with the current technologies R&D of a new product takes
almost 10 years, with a prohibitive cost of $30 million dollar in
part due to the demand for large-scale synthesis of thousands of test
compounds of which only 1 may reach the market. R&D could be expedited
and cost dramatically reduced with a molecular/physiological target to
streamline putative repellents for final efficacy and toxicological
Using olfactory-based choice assay we show here that the fruit fly is
repelled by not only DEET, but also IR3535 and picaridin thus suggesting
they might have “generic repellent detector(s),” which may be of
practical applications in new repellent screenings. We performed single unit
recordings from all olfactory sensilla in the antennae and maxillary palps.
Although the ab3A neuron in the wild type flies responded to picaridin, it
was unresponsive to DEET and IR3535. By contrast, a neuron housed in the
palp basiconic sensilla pb1 responded to DEET, IR3535, and picaridin, with
apparent sensitivity higher than that of the DEET detectors in the
neuron” and showed to be sensitive to the three insect repellents.
For the first time we have demonstrated that the fruit fly avoids not only
DEET but also IR3535 and picaridin, and identified an olfactory receptor
neuron (ORN), which is sensitive to these three major insect repellents. We
have also identified the insect repellent-sensitive receptor, DmOr42a. This
generic detector fulfils the requirements for a simplified bioassay for
early screening of test insect repellents.
Publisher: Public Library of Science
Date Published: 16-March-2011
Author(s): Syed Z., Pelletier J., Flounders E., Chitolina R., Leal W.