Red imported fire ants cover the insecticide-treated surfaces with particles to reduce contact toxicity

• Published in: Journal of pest science Vol. 95; no. 3; pp. 1135 - 1150
• Main Authors: Wen, Chao, Shen, Liming, Chen, Jian, Zhang, Jianlong, Feng, Ying, Wang, Zhong, Chen, Xuan, Cai, Jiacheng, Wang, Lei, He, Yinghao, Wen, Xiujun, Ma, Tao, Wang, Cai
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2022; Springer Nature B.V
• Subjects: Agriculture; Ants; Avermectin; Biomedical and Life Sciences; Chlorfenapyr; Cypermethrin; Ecology; Entomology; Fipronil; Forestry; Insecticide resistance; Insecticides; Invasive insects; Life Sciences; Original Paper; Pesticides; Plant Pathology; Plant Sciences; Rotenone; Solenopsis invicta; Surface treatment; Thiamethoxam; Toxicity; Workers (insect caste); Insecticide resistance; Repellency; Particle-covering behavior; Tool use
• ISSN: 1612-4758; 1612-4766
• DOI: 10.1007/s10340-021-01474-0

Surface treatment is commonly used in controlling the red imported fire ants, Solenopsis invicta Buren. In the present study, the behavioral responses of S. invicta workers to surfaces treated with insecticides were investigated. Toxicological tests showed that beta-cypermethrin had the highest contact toxicity (with the lowest LC 50 value) among nine tested insecticides, followed by thiamethoxam, fipronil, indoxacarb, chlorfenapyr, spinetoram, rotenone, avermectin, and chlorantraniliprole. In the laboratory, surfaces treated with beta-cypermethrin or rotenone significantly reduced the number of foraging ants. In addition, S. invicta workers transported significantly more particles (measured in weight and/or covered area) onto surfaces treated with fipronil (50, 500, and 5000 µg/mL), rotenone (5000 µg/mL), or avermectin (5000 µg/mL) compared with the controls. Similarly, these insecticides significantly triggered the particle-covering behavior of ants in the field. We hypothesized that such behaviors would reduce the contact toxicity of insecticides against S. invicta. When the surfaces treated with fipronil or rotenone (500 or 5000 µg/mL) were artificiality covered with particles, S. invicta had significantly higher LT 50 values compared with insecticide-treated surfaces without particles . This study provides the first evidence that S. invicta workers can perform particle-covering behavior to reduce the toxicity of certain insecticides, which constitutes a unique insecticide-resistance strategy in ants.