Chemical defense secretions of the termite soldiers ofAcorhinotermes andRhinotermes (Isoptera, Rhinotermitinae)

Abstract

The defense secretions of advanced “nasutoid” rhinotermitine soldiers from the New World contain enolic β-ketoaldehydes as the major components. The secretions of minor soldiers ofRhinotermes hispidus (Emerson) andR. marginalis (Emerson) consist primarily of 3-keto-13-tetradecenal and 3-ketotetradecanal, but possess in addition C₁₃, C₁₄, C₁₅, and C₁₇ saturated and unsaturated ketones. Major soldiers lacked these compounds and in fact had virtually no frontal gland secretion. The defense secretion of the monomorphic soldiers ofAcorhinotermes subfusciceps (Emerson) contains mostly 3-keto-(Z)-9-hexadecenal and (Z)-8-pentadecen-2-one. Biosynthetic origins and interrelationships are postulated for these compounds, and the concomitant evolution of chemical weaponry and the modified labral brush is discussed.