My question:Does wearing clothing treated with Permethrin, (bought pretreated or applied at home), harm the very insects we are studying? I know it is toxic to bees, spiders etc and have not been able to find any answers.
1 Like
My understanding is that it does not. Treated clothing causes the ticks to lift their legs off the surface and they end up falling off. It does slowly wear off from machine washing (some reports suggest a significant decline after 16 washings despite what the manufacturers say). Permethrin applied in other ways - aerial spray- is quite toxic to many insects, including butterflies. So unless you are holding a butterfly directly on your treated pants or shirt for a long period, I don’t think this is a problem from what I understand.
1 Like
Here is a recent paper looking at aerial spraying.
Bargar, T.A., Jiang, Y. Adult Mosquito and Butterfly Exposure to Permethrin and Relative Risk Following ULV Sprays from a Truck-Mounted Sprayer. Arch Environ Contam Toxicol 86 , 25–36 (2024). Adult Mosquito and Butterfly Exposure to Permethrin and Relative Risk Following ULV Sprays from a Truck-Mounted Sprayer | Archives of Environmental Contamination and Toxicology
Abstract
Ground applications of adulticides via a specialized truck-mounted sprayer are one of the most common practices for control of flying adult mosquitoes. Aerosols released to drift through a targeted area persist in the air column to contact and kill flying mosquitoes, but may also drift into adjacent areas not targeted by the applications where it may affect nontarget insects such as imperiled butterflies. This study compared the risk of permethrin to adult mosquitoes and adult butterflies to assess the likelihood that the butterflies would be affected following such sprays. Permethrin toxicity values were determined for Aedes aegypti and Culex quinquefasciatus (LD50s of 81.1 and 166.3 ng/g dw, respectively) and then combined with published toxicity data in a species sensitivity distribution for comparison with published permethrin toxicity data for adult butterflies. The sensitivity distributions indicated adult butterflies and mosquitoes are similarly sensitive, meaning relative risk would be a function of exposure. Exposure of adult butterflies and adult mosquitoes to permethrin was measured following their exposure to ULV sprays in an open field. Average permethrin concentrations on adult mosquitoes (912–38,061 ng/g dw) were typically an order of magnitude greater than on adult butterflies (110–11,004 ng/g dw) following each spray, indicating lower risk for butterflies relative to mosquitoes. Despite lower estimated risk, 100% mortality of adult butterflies occurred following some of the sprays. Additional studies could help understand exposure and risk for butterflies in densely vegetated habitats typical near areas treated by ULV sprays.
1 Like