Identification and field evaluation of sex pheromone for Erannis ankeraria Staudinger (Lepidoptera: Geometridae)

BACKGROUND Erannis ankeraria (Staudinger) (Lepidoptera: Geometridae) is a defoliator of Larix , Quercus , and Picea trees. Recent outbreaks of this pest have caused extensive damage to the larch forests in north-eastern China RESULTS Through gas chromatography-electroantennographic detection (GC-EAD) and gas chromatography–mass spectrometry (GC–MS), Z 3 Z 6 Z 9-19:Hy, Z 3 Z 9- cis -6,7-epo-19:Hy, Z 6 Z 9- cis -3,4-epo-19:Hy, and Z 3 Z 6- cis -9,10-epo-19:Hy were identified from sex pheromone glands of Erannis ankeraria females. The quaternary mixture of these synthetic pheromone components at a ratio of 1:0.5:1.2:1.3 achieved the optimal trapping effect in field experiments. Biotransformation and activity assays revealed that Z 3 Z 6 Z 9-19:Hy serves as a precursor of epoxynonadecadienes, regulates the upwind flight behavior of male moths, and exhibits a synergistic effect with the epoxy pheromone components. Notably, the 3,4- and 9,10-epoxides, newly identified in the genus Erannis , both markedly decrease the captures of Colotois pennaria (Lepidoptera: Geometridae) CONCLUSIONS The sex pheromone of Erannis ankeraria was identified as a quaternary blend, which exhibits a remarkable efficacy in attracting Erannis ankeraria males, thereby offering a reliable tool for population monitoring. Z 3 Z 6 Z 9-19:Hy acts as a precursor in the biosynthesis of three epoxynonadecadiene pheromone components, and is also a critical synergistic pheromone component. The 3,4- and 9,10-epoxides likely mediate interspecific chemical communication between Erannis ankeraria and C. pennaria , enabling species-specific recognition and reproductive isolation © 2025 Society of Chemical Industry.