Volatile constituents of male and female boll weevils and their frass

The volatile constituents of male and female boll weevils, Anthonomus grandis, and their frass were analysed by GLC-MS. The 4 previously identified components of the male pheromone were present only in the male volatile oil (3·9%) and in the male frass volatile oil (38·9%). The compounds found in one or both sexes and their frass include 26 carbonyls, 23 hydrocarbons, 12 alcohols, 6 phenols, 4 esters, 3 furans, 1 ether, and 1 lactone. Also found were 2 compounds containing nitrogen, 1 halogen, and 1 sulphur. There were 33 terpenes and 24 aromatic compounds. 3,7-Dimethyl-1-octanol comprised 15·6 per cent of the male frass oil. Carvone was found only in females (5·4%) and in female frass (6·8%). A series of monoterpene aldehydes (M⁺ 152) were found only in the female frass oil. A pheromone rôle for these components was suggested.