Walter Soares Leal (born February 2, 1954) is a Brazilian biochemist and entomologist who is known for identifying pheromones[1] and mosquito attractants,[2][3] and elucidating a mechanism of action of the insect repellent DEET.

[citation needed] While still residing in Japan, Leal attended the University of Tsukuba, division of Applied Biochemistry, graduating with a Ph.D. three years later.

[23] In 2005, Leal coined the term “reverse chemical ecology” for employing olfactory proteins to identify semiochemicals of potential practical applications.

His laboratory identified olfactory receptor neurons (ORNs) highly sensitive to nonanal, which might play a crucial role in Culex mosquitoes shifting from birds to humans, implicated in West Nile virus transmission.

[27] Leal and collaborators discovered a receptor, CquiOR32, with dual inhibitory/excitatory properties manifested in the Xenopus oocyte recording system, in flies and mosquito behavior.