Four species of noctuid moths degrade sex pheromone by a common antennal metabolic pathway

Abstract

Z-9-tetradecenyl acetate (Z-9 14:OAc) is a component in the female sex pheromones of the cabbage looper, Trichoplusia ni (Hubner), beet armyworm, Spodoptera exigua (Hubner), fall armyworm, Spodoptera frugiperda (J. E. Smith), and black cutworm, Agrotis ipsilon (Hufnagel). We compared the in vivo catabolism of Z-9-14:OAc in time course fashion after the tritiated compound was applied topically to the antennae of males in the four species. Catabolism of tritiated European corn borer, Ostrinia nubilalis (Hubner), sex pheromone (Z-11-14:OAc) was monitored concomitantly so direct comparisons could be made between the male borer and the noctuid males. Results showed that catabolism of pheromone in all four noctuid moths proceeded along the same hydrolysis-alcohol oxidation pathway as has been observed in the European corn borer male. Catabolism was mathematically modeled with first- order differential equations as a four-compartment degradative system in which tritiated pheromonal acetate was sequentially converted to tetradecenol, tetradecenoic acid and water. The modeling revealed subtle differences in catabolism from one species to another and that most species exhibited a finite capacity to catabolize the pheromone.