Neonicotinoid exposure causes behavioral impairment and delayed mortality of the federally threatened American burying beetle, Nicrophorus americanus

PLoS ONE
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Abstract

Among the most immediate drivers of American burying beetle (Nicrophorus americanus Olivier) declines, nontarget toxicity to pesticides is poorly understood. Acute, episodic exposure to neonicotinoid insecticides at environmentally relevant concentrations is linked to negative impacts on beneficial terrestrial insect taxa. Beyond mortality, behavioral indicators of toxicity are often better suited to assess sublethal effects of residual concentrations in the environment. First, Nicrophorus spp. congeners were used to generate and identify a low-dose exposure rate (lethal dose 10%; LD10) from an acute, 24-hour exposure and the concentration-series was confirmed by LC–MS/MS. Next, we evaluated the effects of single and repeated low-dose (LD10 = 58.9 ng/beetle) imidacloprid exposure on Namericanus behavior (10 minutes post-dose) and mortality (10 days post-dose). Behavior parameters were analyzed using EthoVision-XT. Control Namericanus were significantly less mobile, demonstrating death-feigning, an anti-predator behavior. Single LD10 dosed Namericanus were hyperactive, traveling over 4 times farther (total distance; p = 0.03) and faster (mean velocity; p = 0.02) than controls. Single and repeated LD10 dosed Namericanus extended their wings without taking flight and flipped on their backs. All control Namericanus survived 10 days post-dose; single LD10 and repeated LD10 exhibited 30% and 50% mortality, respectively. A single LD10 exposure event was sufficient to significantly elicit greater movement and high predation risk behaviors, whereas repeated LD10 exposure did not worsen behavioral impairment but increased mortality over time. Collectively, generalized linear mixed effects models indicated that distance traveled, velocity, and extended wings were significant predictors of mortality. Recently reclassified, the federally threatened Namericanus may be at greater risk to insecticide exposure than previously thought and vulnerable to episodic, low-dose neonicotinoid exposure.

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Publication type Article
Publication Subtype Journal Article
Title Neonicotinoid exposure causes behavioral impairment and delayed mortality of the federally threatened American burying beetle, Nicrophorus americanus
Series title PLoS ONE
DOI 10.1371/journal.pone.0314243
Volume 20
Issue 1
Year Published 2025
Language English
Publisher PLoS
Contributing office(s) California Water Science Center
Description e0314243, 17 p.
Country United States
State Nebraska, Oklahoma
City Braggs, O'Neill
Other Geospatial Camp Gruber
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