Lysine and Alanine as Mosquito Attractants1

Abstract

L-lysine was found to be an attractant for Aedes aegypti that is present in human blood. L-alanine was also attractive, while L-arginine was slightly attractive. All the other amino acids tested were either not attractive or actually repellent. Nitrogenous bases were either unattractive, e.g., asparagine, ornithine and ammonia, or repellent, e.g., cadaverine and putrescine. Column chromatography showed that the compounds responsible for the attractiveness of 11 different protein hydrolysates, beef blood plasma and human blood plasma were firstly L-lysine, secondly L-alanine, and possibly L-arginine, D-lysine was also attractive. L-lysine was attractive in extreme dilution, i.e., down to 1 ppm, and its vapour activated resting mosquitoes. It was attractive also to Aedes stimulans, Culex pipiens, and four strains of A. aegypti. Chemical confirmation has been obtained that L-lysine actually distils with water vapor.