Chemical ecology of astigmatid mites XLIX β-Acaridial (2(E)-(4-methyl-3-pentenylidene)-butanedial), the alarm pheromone of Tyrophagus longior Gervais (Acarina : Acaridae)

Abstract

Alarm pheromone activity was detected in the hexane extract of Tyrophagus longior. The GLC profile of the extract revealed six components ; α-acaridial {2(E)-(4-methyl-3-pentenyl)-butanedial}, tridecane, β-acaridial {2(E)-(4-methyl-3-pentenylidene)-butanedial}, an unknown (M⁺ ; m/z 166), n-hexyl linolate and n-hexyl stearate, among which β-acaridial was the major component, followed by tridecane. These compounds were each identified by GC/MS spectra and GLC retention times by comparing with those of authentic compounds. The active eluate from a SiO₂ column by 50% ether in hexane consisted of a peak of β-acaridial. The compound isolated from the mite was active at 50 ng, and its activity was the same as the authentic β-acaridial derived from T. putrescentiae.