Isopropylesters as wetting agents from the defensive secretion of the rove beetle Coprophilus striatulus F. (Coleoptera, Staphylinidae)

Abstract

The defensive gland secretion of the rove beetle Coprophilus striatulus F. (Staphylinidae), Oxytelinae) has been shown to contain p- toluquinone , p- toluhydroquinone and a series of long chained saturated and unsaturated iso propylesters which were demonstrated by gas chromatography and mass spectrometry. The co-occurrence of at least five free fatty acids was confirmed by gas chromatography. The defensive glands of C. striatulus represent the first reported source of iso propylesters from defensive glands of insects. By contact angle measurements synthetic quinoid iso propylester mixtures have been shown to possess excellent wetting properties on chitin surfaces. Moreover the quinoid iso propylester mixture was highly effective against immersed Calliphora erythrocephala larvae. As a primitive member of the Oxytelinae C. striatulus differs distinctly from derived species of the same subfamily both with respect to the defensive gland morphology and the chemistry of the secretion.