The Ecological and Evolutionary Implications of Pyrethroid Exposure: A New Perspective on Aquatic Ecotoxicity

Abstract

Pyrethroids are one of the most heavily used insecticide classes globally because they have low mammalian toxicity. However, they are highly toxic to arthropods. Pyrethroids are ubiquitous in the aquatic environment as a result of urban (landscaping, structural pest control, home, and garden) and agricultural runoff and spray drift, often at levels that exceed water quality benchmarks established for the protection of aquatic life. Pyrethroids also enter the aquatic compartment through direct application to treat crustacean parasites in commercial fisheries. Here, we briefly review the acute and sublethal toxicities of pyrethroids with a focus on aquatic invertebrates. Our primary focus is on evidence of the evolution of adaptive pyrethroid resistance in aquatic invertebrates (sea lice (Lepeophtheirus salmonis), mosquitoes (Anopheles gambiae and A. coluzzi) black flies (Simulium spp.), and amphipods (Hyalella azteca)) driven by target and nontarget applications of pyrethroids in the aquatic environment. We explore the human health, evolutionary, ecological, and risk assessment implications of the evolution of pyrethroid resistance and suggest using resistance in the model invertebrate H. azteca to further our understanding of evolutionary toxicology in wild populations.