CHEMISTRY OF METAPLEURAL GLAND SECRETIONS OF 3 ATTINE ANTS, ATTA-SEXDENS-RUBROPILOSA, ATTA-CEPHALOTES, AND ACROMYRMEX-OCTOSPINOSUS (HYMENOPTERA, FORMICIDAE)

The chemical composition of the secretions of the metapleural glands o f workers and soldiers of two Atta species, Atta sexdens rubropilosa a nd A. cephalotes, and workers of Acromyrmex octospinosus, has been stu died. As indicated by infrared spectrometry and confirmed by the ninhy drin test, the secretions contain chiefly proteins. Of the volatile ac idic portion, which is present as ionized salts, phenylacetic acid is the major component in workers and soldiers of A. s. rubropilosa and A . cephalotes. Both Atta species also contain 3-hydroxydecanoic acid an d its homolog as minor components together with indoleacetic acid. Whi le there are qualitative similarities in the acidic composition in the secretions of A. s. rubropilosa and A. cephalotes, they differ quanti tatively. The secretion of Acromyrmex octospinosus contains 3-hydroxyd ecanoic and indoleacetic acids, bur lacks phenylacetic acid. The bacte ricidal and fungicidal actions of the three major substances have been confirmed.