Anandasankar Ray, an associate professor of entomology at the University of California at Riverside, and colleagues reported the discovery of the DEET (N,N-diethyl-m-toluamide) receptors in insects and the testing of three FDA approved safe alternatives to DEET in the Oct. 2, 2013, issue of the journal Nature.
The problems with DEET are a known interference with the action of the enzyme acetylcholinesterase, the compound melts some plastics and nylon, and DEET is impractical and too costly in African countries where malarial mosquitoes are a health concern.
The DEET-detecting olfactory receptors that cause the repellency behavior were discovered by fluorescent labeling of neurons in fruit flies. The receptors are called Ir40a receptors and line the structure on insect antenna called the sacculus.
The researchers used a set of computer algorithms to search a huge database for compounds that had the repellency of DEET, did not melt plastics, and were FDA approved. They found three compounds that met the criteria that are derived from plants or animals and are presently being used in FDA approved cosmetics.
The new insect repellents offer the advantage of longer duration of repellency than DEET and the ability to use the compounds in large areas.
The discovery of the locus of function of DEET will enable better mosquito control as well as flies, lice, bed bugs, ants, cockroaches, grain pests and agricultural pests.