Details

Autor(en) / Beteiligte

• Taylor-Wells, Jennina
• Gross, Aaron D.
• Jiang, Shiyao
• Demares, Fabien
• Clements, Joseph S.
• Carlier, Paul R.
• Bloomquist, Jeffrey R.

Titel

Toxicity, mode of action, and synergist potential of flonicamid against mosquitoes

Ist Teil von

• Pesticide biochemistry and physiology, 2018-10, Vol.151, p.3-9

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• The present study focused on the toxicity of the aphid anti-feedant flonicamid and its main metabolite, 4-trifluoromethylnicotinamide (TFNA-AM) to Aedes aegypti and Anopheles gambiae mosquitoes. The compounds were toxic to both species via topical application, resulting in un-coordinated locomotion and leg splaying, with a favorable An. gambiae LD50 value of 35 ng/mg for TFNA-AM, but no significant lethality to Ae. aegypti at 10 μg/female. There was mild cross resistance in the Akron-kdr (Akdr) strain of An. gambiae. Both compounds were non-toxic to intact larvae (LC50 > 300 ppm); however, headless Ae. aegypti larvae displayed spastic paralysis, with PC50 values of 2–4 ppm, indicating that the cuticle is a significant barrier to penetration. TFNA-AM showed low mammalian toxicity, with an LD50 of >2000 mg/kg in mice. Electrophysiological experiments showed larval Aedes muscle depolarization and Kv2 channel blocking activity that required near mM concentrations, suggesting that this potassium channel is not the main target for flonicamid nor its metabolite. However, TFNA-AM was a potent blocker of evoked body wall sensory discharge in dipteran larvae, suggesting that some component of the chordotonal organ system may be involved in its toxicity. Finally, flonicamid and TFNA-AM showed about 2-fold synergism of permethrin toxicity against An. gambiae adult females whose mechanism should become more clear once the mode of action of these compounds is better defined. [Display omitted] •Flonicamid and its metabolite TFNA-AM had toxic and behavior-modifying properties.•Cross resistance in the Akdr strain of Anopheles gambiae was low.•The compounds depolarized Aedes muscle and blocked the Kv2 channel at near mM concentrations.•TFNA-AM (2 μM), but not flonicamid, blocked firing of sensory nerves.•Primary site of action is chordotonal organs, with some effects on potassium channels.