Chemical Ecology of Astigmatid Mites : XXXVII. Fatty Acid as Food Attractant of Astigmatid Mites, Its Scope and Limitation

Abstract

The following four species of acarid mites were attracted not only to methyl esters of naturally occurring saturated and unsaturated fatty acids (C16-C18) as food attractants and (or) arrestants, but also to their corresponding free acids : Dermatophagoides farinae, D. pteronyssinus, Tyrophagus putrescentiae and Lardoglyphus konoi. Four other species, Carpoglyphus lactis, Aleuroglyphus ovatus, Glycyphagus demesticus and Acarus immobilis indicated no activity to any of those acids and esters. There was no difference in activity between any free fatty acids and their esters, or among fatty acids and esters. T. putrescentiae was 10 times more sensitive than the three other responsive species and responded to 10 μg-doses of fatty acids and methyl esters. The three other species gave positive responses to 100 μg-doses of fatty acids and esters. The three responsive species, L. konoi, D. farinae and T. putrescentiae were commonly attracted to pentadecanoic acid likewise to the natural fatty acids, while the other acids with even- and odd-numbered carbons from C7 to C20 were sporadically active, depending on species. Elaidic acid, the non-natural geometric isomer of oleic acid, was only active to D. farinae among the three species.