Studies on Mosquito Attractants and Stimulants : V. Gas-Chromatographic Separation of the Attractants for Oviposition of Culex pipiens fatigans from the Field Water

Abstract

The author has already demonstrated the exstence of the attractive factor for mosquito oviposition in the pulluted field water. The attractans were separated by gas-chromatography and preliminary attempts of the chemical identification were made. Four compounds from the neutral fraction of the ehter-extract were found to be attractive, while, the phenolic, basic and acidic fractions were highly stimulative for mosquito oviposition. Two out of the four attracrive compounds were found only in the summer waters when Culex pipiens pallens bred aboundantly. Further bioassay on the semiquantitative bases revealed that these four compounds were effective to the extremely low concentrations to C. p. fatigans as well as C. p. pallens but not to Aedes aegyti.Using the infrared and mass spectroscopies the chemical structures of the three attractive compounds were presumed to be 2-butoxyethanol, a saturated open chain ketone and a toluic acid ester with a fairly long unsaturated alcohol, repsectively. The attractiveness of the first compound commercially obtained was, however, controversial.