Two Fatty Acids From Host Plant Leaves Are Attractive to Soritia leptatina Adults

Quercus aquifolioides is an ecologically important oak species on the Qinghai-Tibet Plateau that experiences significant damage from Soritia leptatina. To clarify the behavioral response of S. leptatina to leaf volatiles of Q. aquifolioides, we analyzed leaf-associated volatile organic compounds using solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS), measured electrophysiological and behavioral responses of adult S. leptatina to selected leaf volatiles using electroantennography (EAG) and Y-tube olfactometer assays, and evaluated the field-trapping potential of bioactive volatiles. The detected leaf-associated profile included C6 green-leaf-volatile derivatives, long-chain fatty acids and fatty-acid esters, terpenes, and aromatic compounds. Unmated male and female adults showed strong EAG responses to leaf acetate, palmitic acid, and myristic acid, with the highest response recorded for 10 µg/µL leaf acetate (0.97 mV). Y-tube assays indicated that leaf acetate, myristic acid, and naphthalene elicited significant behavioral attraction at specific concentrations (P < 0.05), whereas palmitic acid did not show significant attraction in this assay. Field trapping experiments further showed that palmitic acid and myristic acid increased adult captures, with 100 µg/µL myristic acid producing the highest catch (137 individuals). These results suggest that myristic acid and palmitic acid may be useful for monitoring, early warning, and environmentally friendly management of S. leptatina, although their behavioral roles should be interpreted according to assay type and concentration.