Evidence of Pheromone Catabolism Via β-Oxidation in the European Corn Borer (Lepidoptera: Crambidae)

Experiments were conducted using tritiated European corn borer, Ostrinia nubilalis (Hübner), pheromone, (Z)-[11,12-³H₂]-11-tetradecen-1-ol acetate, a tritiated fluorinated analog of the European corn borer pheromone, 2-fluoro-(Z)-[11,12-³H₂]-11-tetradecen-1-ol acetate, and methyl-4-bromocrotonate (MBC) to determine if pheromone catabolism proceeds on the moth's antennae via the β-oxidation pathway of fatty acid degradation. When antennae were treated with tritiated natural pheromone plus MBC (a precursor of the known β-oxidation inhibitor, 4-bromocrotonic acid), catabolism of the pheromone was significantly inhibited. When the 2-fluoro pheromone analog was applied alone to antennae, it was hydrolyzed to the corresponding alcohol but was not degraded. MBC had no effect on catabolism of the 2-fluoro analog, and 2-fluoro substitution inhibited entrance of the compound into β-oxidation. These results demonstrate that β-oxidation is the primary oxidative pathway by which pheromone is degraded on the antennae of European corn borer moths.