Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption

• Published in: PeerJ (San Francisco, CA) Vol. 8; p. e8669
• Main Authors: Bargar, Timothy A, Hladik, Michelle L, Daniels, Jaret C
• Format: Journal Article
• Language: English
• Published: United States PeerJ. Ltd 10.03.2020; PeerJ, Inc; PeerJ Inc
• Subjects: Bees; Butterflies & moths; Clothianidin; Conservation Biology; Contamination; Danaus plexippus; Entomology; Insecticides; Leaves; Monarch butterfly; Mortality; Neonicotinoid; Pesticides; Pollinators; Pupation; Seeds; Soils; Swamp milkweed; Toxicity; Toxicology; Wildlife conservation; United States > US; Neonicotinoid; Swamp milkweed; Monarch butterfly; Toxicity; Clothianidin
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.8669

Recent concern for the adverse effects from neonicotinoid insecticides has centered on risk for insect pollinators in general and bees specifically. However, natural resource managers are also concerned about the risk of neonicotinoids to conservation efforts for the monarch butterfly ( ) and need additional data to help estimate risk for wild monarch butterflies exposed to those insecticides. In the present study, monarch butterfly larvae were exposed in the laboratory to clothianidin via contaminated milkweed plants from hatch until pupation, and the effects upon larval survival, larval growth, pupation success, and adult size were measured. Soils dosed with a granular insecticide product led to mean clothianidin concentrations of 10.8-2,193 ng/g in milkweed leaves and 5.8-58.0 ng/g in larvae. Treatment of soils also led to clothianidin concentrations of 2.6-5.1 ng/g in adult butterflies indicating potential for transfer of systemic insecticides from the soil through plants and larvae to adult butterflies. Estimated LC s for total mortality (combined mortality of larvae and pupae) and EC50 for larval growth were variable but higher than the majority of concentrations reported in the literature for clothianidin contamination of leaves.