C-7-3

PHEROMONE CATABOLISM VIA J-OXIDATION IN THE EUROPEAN CORN BORER, OSTRINIA NUBILALIS (LEPIDOPTERA: PYRALIDAE).

Jerome A. Klun, Achot K. Khrimian, James E. Oliver, Brian K. Penney¹ and Anup L. Pamnani
Insect Chemical Ecology Laboratory, 10300 Baltimore Ave., USDA, ARS, Beltsville Ag. Research Centre, Bldg. 007, Beltsville, MD 20705-2350, USA.
¹Dept. of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.

Experiments were conducted using tritiated European corn borer (ECB) pheromone, (Z)-[11,12-³H₂]-11-tetradecenyl acetate, and a tritiated fluorinated analog of the ECB pheromone, 2-fluoro-(Z)-[11,12-³H₂]-11-tetradecenyl acetate, to determine if pheromone catabolism proceeds on the moth’s antennae via the J-oxidation pathway of fatty acid degradation. Compared to control antennae treated with tritiated pheromone, antennae treated with methyl-4-bromocrotonate (a precursor of the J-oxidation inhibitor, 4-bromocrotonic acid) plus tritiated pheromone, produced significantly less proportional amounts of tritiated water in time-course assays. When the fluorinated analog was applied to antennae, significantly less tritiated water was formed compared to control antennae treated with the same quantity of tritiated natural pheromone. Further, antennae treated with the fluorinated analog alone or analog plus J-oxidation inhibitor produced the same amounts of labelled water. This indicates that 2-fluoro substitution ostensibly interfered with entrance of the compound into J-oxidation. The combined results provide evidence that the J-oxidation is a post-chemoreceptive pathway by which pheromone is degraded on the insect’s antennae.