Repellants can be very useful in managing red imported fire ants, Solenopsis invicta Buren, particularly in some scenarios where application of synthetic insecticides is not appropriate. Our previous study showed that fire ants cannot transport food on surfaces treated with eugenol, and the repelling effect lasted for > 24 h, which motivated us to extend our research on eugenol derivatives. Herein, the electrophysiological effect, toxicity and repellency of five eugenol derivatives (methyl isoeugenol, eugenol acetate, isoeugenol, methyl eugenol, and isoeugenyl acetate) were evaluated against S. invicta workers. All eugenol derivatives triggered significantly higher EAG responses than the hexane blanks and had concentration-dependent toxicity against S. invicta workers. All tested eugenol derivatives except isoeugenyl acetate showed strong repellency by significantly decreasing the number of defending (aggression mode) and foraging (non-aggression mode) ants in the tested arenas. Unexpectedly, methyl isoeugenol almost repelled all defending fire ants from disturbed mounds. This compound also repelled foraging ants significantly longer than eugenol. At the concentration of 50 mg/kg in sand, methyl isoeugenol was the only tested compound that completely suppressed the digging behavior of S. invicta workers. In addition, fire ants exhibited low levels of nesting behaviors in flowerpots containing sand treated with each eugenol derivative (500 mg/kg). Surprisingly, the repellency of methyl isoeugenol in flowerpots containing treated sand could last for almost one month. Our study may bring an opportunity to develop strong and long-lasting fire ant repellant products against foraging, defending, and nesting fire ants.

驱虫剂在管理红火蚁（ Solenopsis invicta Buren）方面非常有用，特别是在某些不适合使用合成杀虫剂的情况下。我们之前的研究表明，火蚁不能在丁香酚处理过的表面上运输食物，并且排斥作用持续> 24小时，这促使我们扩展了对丁香酚衍生物的研究。在此，评估了五种丁香酚衍生物（甲基异丁香酚、乙酸丁香酚、异丁香酚、甲基丁香酚和乙酸异丁香酚）对S. invicta工人的电生理效应、毒性和排斥性。与己烷空白相比，所有丁香酚衍生物引发显着更高的 EAG 响应，并且对S. invicta具有浓度依赖性毒性工人。除乙酸异丁香酯外，所有测试的丁香酚衍生物都通过显着减少测试场地中防御（攻击模式）和觅食（非攻击模式）蚂蚁的数量而显示出强烈的驱避性。出乎意料的是，甲基异丁香酚几乎将所有防御火蚁从扰乱的土堆中击退。这种化合物也比丁香酚更长时间地排斥觅食的蚂蚁。在沙中 50 mg/kg 的浓度下，甲基异丁香酚是唯一完全抑制S. invicta挖掘行为的测试化合物工人。此外，火蚁在含有用每种丁香酚衍生物 (500 mg/kg) 处理的沙子的花盆中表现出低水平的筑巢行为。令人惊讶的是，含有处理过的沙子的花盆中甲基异丁香酚的排斥性可持续近一个月。我们的研究可能会带来一个机会来开发强大和持久的火蚁驱避剂产品，以对抗觅食、防御和筑巢的火蚁。