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Comparative toxicity of two neonicotinoid insecticides at environmentally relevant concentrations to telecoprid dung beetles.

Authors :
Cavallaro MC
Hladik ML
Hittson S
Middleton G
Hoback WW
Source :
Scientific reports [Sci Rep] 2023 May 26; Vol. 13 (1), pp. 8537. Date of Electronic Publication: 2023 May 26.
Publication Year :
2023

Abstract

Dung beetles (Coleoptera: Scarabaeinae) frequently traverse agricultural matrices in search of ephemeral dung resources and spend extended periods of time burrowing in soil. Neonicotinoids are among the most heavily applied and widely detected insecticides used in conventional agriculture with formulated products designed for row crop and livestock pest suppression. Here, we determined the comparative toxicity of two neonicotinoids (imidacloprid and thiamethoxam) on dung beetles, Canthon spp., under two exposure profiles: direct topical application (acute) and sustained contact with treated-soil (chronic). Imidacloprid was significantly more toxic than thiamethoxam under each exposure scenario. Topical application LD50 values (95% CI) for imidacloprid and thiamethoxam were 19.1 (14.5-25.3) and 378.9 (200.3-716.5) ng/beetle, respectively. After the 10-day soil exposure, the measured percent mortality in the 3 and 9 µg/kg nominal imidacloprid treatments was 35 ± 7% and 39 ± 6%, respectively. Observed mortality in the 9 µg/kg imidacloprid treatment was significantly greater than the control (p = 0.04); however, the 3 µg/kg imidacloprid dose response may be biologically relevant (p = 0.07). Thiamethoxam treatments had similar mortality as the controls (p > 0.8). Environmentally relevant concentrations of imidacloprid measured in airborne particulate matter and non-target soils pose a potential risk to coprophagous scarabs.<br /> (© 2023. The Author(s).)

Details

Language :
English
ISSN :
2045-2322
Volume :
13
Issue :
1
Database :
MEDLINE
Journal :
Scientific reports
Publication Type :
Academic Journal
Accession number :
37237012
Full Text :
https://doi.org/10.1038/s41598-023-35262-w