JACKSON HOLE, WYO – Mosquito season will be here soon, prompting the age-old question: What repellent actually works?
The Journal of Insect Science tested the efficacy of a spectrum of commercially available insect repellents for Aedes aegypti and Aedes albopictus known by scratchers and slappers everywhere as ‘skeeters.’
It’s more than just the inconvenience of getting bit, mosquitoes are hosts for an array of different protozoan parasites, nematodes, and viruses. Controlling mosquito populations is an effective tool for the fight against such pathogens. Several different methods for mosquito control have been developed. Source reduction via spraying, physical exclusion with nets and screens, the release of genetically modified mosquitoes, and pesticide application have all been tried around the world to varying degrees of success.
Mosquitos find you and your blood by a sense of smell. Insect olfaction has been extensively studied leading to the identification of the key proteins involved: odorant receptors, odorant receptor co-receptors, gustatory receptors, and odorant binding proteins. The processing of olfactory information in different regions of the insect brain has also attracted a lot of research interest.
Various mosquito attractants and repellents have been identified, many of which are produced by human metabolism or the bacterial degradation of sweat components. Lactic acid and 1-octen-3-ol are two components that act as strong mosquito attractants.
Carbon dioxide from breath is another strong attractant that sensitizes mosquitoes to other odorants. Studies have shown that different insect repellents use a similar mode-of-action. Each repellent binds and interacts with specific insect odorant and gustatory receptors changing their activity and thereby exerting their deterrent effects.
The most widely used insect repellent, DEET (N,N-diethyl-m-toluamide), has been in use for about 70?years. DEET is considered a very safe repellent. Nevertheless, fear of possible side effects of DEET and general ‘chemophobia’ has resulted in the development of a multitude of ‘DEET-free’ mosquito repellents with a variety of active ingredients. Plant-based repellents usually contain essential plant oils as active ingredients.
A 2015 study by Journal of Insect Science tested everything from Skin So Soft to OFF Deep Woods, purchasing repellents locally in Las Cruces, New Mexico, or ordered online via Amazon.
The following observations were made: