Objective Solenopsis invicta Buren (RIFA) is a highly harmful invasive insect species, and the use of chemically synthesized pesticides for its control carries various potential negative impacts. Plant essential oils (EOs) can regulate insect behavior and have the potential to be developed into environmentally friendly insect repellents or attractants. Ailanthus altissima (Mill.) Swingle is a deciduous tree belonging to the genus Ailanthus in the family Simaroubaceae, and its leaves possess a distinctive odor.

Method In this study, the EO from A. altissima leaves was extracted using steam distillation, and a Y-tube olfactometer was used to test the behavioral effects of the EO on different castes of RIFA. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-electroantennographic detection (GC-EAD) were employed to analyze the main chemical components of the EO and the GC-EAD active compounds.

Result The results showed that, except for the virgin queen ants, all other castes exhibited repellent activity, with small worker ants showing the highest activity. The repellency rates for small worker ants at concentrations of 1 000, 200 and 40 μg/mL were 80.00%, 73.75%, and 65.00%, respectively. In contrast, the virgin queen ants displayed strong attraction, with attraction rates of 75.00% and 70.00% at concentrations of 1 000 and 200 μg/mL, respectively. A total of 38 compounds were identified, accounting for 92.171% of the total content. Among them, cyclohexane and benzopyran-2-one exhibited the highest concentrations at 14.820% and 11.554%, respectively. A total of 19 compounds were detected in the GC-EAD analysis, but only eight were identified: Benzyl alcohol, phenethyl alcohol, trans-(+)-carveol, eugenol, trans-caryophyllene, epoxy alloaromadendrene, tridecane, and oleamide. Seven of these compounds, excluding trans-(+)-carveol, were purchased and tested for their regulatory effects on RIFA behavior. The results showed that at 100 μg/mL, the repellency rates of male ants to trans-caryophyllene and eugenol were both 65.00%. At 1 000 μg/mL, the repellency rates of small worker ants to tridecane and oleamide were both 68.75%. At concentrations of 1 000 and 100 μg/mL, the repellency rates of large worker ants to tridecane were 68.75% and 63.75%, respectively.

Conclusion Clearly, trans-caryophyllene, eugenol, oleamide, and tridecane in the EO of A. altissima leaves are behaviorally active compounds. The findings of this study not only reveal the material basis for the repellent effect of A. altissima leaves on RIFA but also provide a foundation for the development of plant-derived repellents against RIFA.