Researchers at Vanderbilt University have identified a new family of odor sensors that mosquitoes use to locate their prey. Their discovery could help explain the puzzling mechanisms behind the mosquito’s sense of smell and further the discovery of new deterrents and traps. Funded by NIAID, the study was published in the journal PLoS Biology in August 2010.
Mosquitoes’ olfactory system, or sense of smell, is crucial for their survival. Mosquitoes use it to identify mates and locate a host. While its importance is well-accepted, the exact mechanisms behind the mosquito’s olfactory system are poorly understood.
For about 10 years, scientists have been examining Anopheles gambiae, the primary vector of malaria, and studying a set of odor sensors called AgORs (A. gambiae odorant receptors). Now, the Vanderbilt team, led by Laurence Zwiebel, Ph.D., has discovered a new set of receptors, AgIRs (A. gambiae variant ionotropic receptors) by examining the larval olfactory system.
“Mosquito larvae are a good model because their olfactory system is simpler than that of adult mosquitoes,” says Adriana Costero, Ph.D., a Program Officer in the NIAID Vector Biology Research Program. “Using a simpler model within the same species is a novel way of studying vectors.”
In the latest study, Dr. Zwiebel’s team used gene silencing and behavioral analyses to confirm that the common insect repellent DEET activates a specific AgOR. They also identified genes that code for nearly 50 versions of the new type of receptor.
The AgIRs structure was found to be quite different than that of the AgOR receptors. This difference could help explain how mosquitoes are attracted to human odors. Such knowledge may prove critical in developing new traps and repellents to deter mosquitoes that spread infectious diseases such as malaria, dengue, and West Nile virus.
“If we can prevent mosquitoes from finding us, we can prevent them from transmitting diseases,” says Dr. Costero.
Liu C et al. Distinct Olfactory Signaling Mechanisms in the Malaria Vector Mosquito Anopheles gambiae. PLoS Biol 8(8): e1000467. doi:10.1371/journal.pbio.1000467 (2010).
Last Updated March 09, 2011