Effects of permethrin and amitraz on gas exchange and water loss in unfed adult females of Amblyomma americanum (Acari: Ixodidae)

► Permethrin treatment of ticks increased discontinuous gas exchange frequency and caused significant water loss. ► Amitraz abolished the normal rhythmic CO2 release pattern, resulting in an elevated and long-lasting CO2 release. ► Acaricide mixture elicited the strongest CO2 release and water loss. ► This study provided new insights into acaricide modes of action and mechanism of synergism.