Identification and field evaluation of sex pheromone for <i>Erannis ankeraria</i> <scp>Staudinger</scp> ( <scp>Lepidoptera: Geometridae</scp> )

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), Z3Z6Z9-19:Hy, Z3Z9-cis-6,7-epo-19:Hy, Z6Z9-cis-3,4-epo-19:Hy, and Z3Z6-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 Z3Z6Z9-19: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. Z3Z6Z9-19: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.