The secret to keeping mosquitoes at bay may be buried within our own skin. Researchers led by Ulrich R. Bernier of USDA’s Agricultural Research Service, in Gainesville, Fla., reported that certain compounds secreted through human skin or formed by bacteria on the skin can render people invisible to mosquitoes. The researchers have been working on the project since the 1990s while trying to answer the question: What makes certain people more attractive than others to mosquitoes? Bernier’s team is still searching for a definitive answer to that question, but meanwhile they have discovered that small heterocycles, such as 1-methylpiperazine, can effectively cloak a person from detection by Aedes aegypti mosquitoes. The compounds don’t work like DEET, or N,N-diethyl-m-toluamide, the active ingredient in many bug sprays that repels the biting insects. Rather, the small heterocycles make it so the mosquitoes don’t realize a person is in the vicinity. The compounds could be used to make novel bite-prevention creams and lotions for folks who don’t like the smell or astringency of DEET. Bernier and colleagues have patented the compounds for these uses (U.S. Patent 8,207,157 B2).