Study Adds to Findings of Neonic Insecticides’ Threat to Soil Communities; Ground Beetles at Risk

(Beyond Pesticides, June 5, 2025) A study conducted in Pennsylvania and published in Environmental Entomology highlights threats to nontarget organisms from neonicotinoid insecticide exposure. Using species of ground beetles as an example, the study documents sublethal behavioral effects as well as decreased week-long survival. This research fills a notable gap in current research, with the authors explaining, “Predatory soil arthropods are under-represented in insecticide toxicity studies, severely limiting our understanding of how insecticides affect soil-invertebrate communities in agroecosystems.”

The researchers continue, “As a step toward addressing this issue, we conducted novel acute oral, topical, and soil-based toxicity assays on 9 ground beetle species (Coleoptera: Carabidae) in response to the neonicotinoid insecticides clothianidin, thiamethoxam, and imidacloprid.” The nine carabid beetle species, all common to agroecosystems in central Pennsylvania, were exposed to clothianidin, while additional assays with thiamethoxam and imidacloprid were conducted on the two most abundant species.

A wide body of science exists that connects neonicotinoid exposure to health effects in a variety of nontarget organisms. Neonicotinoids, a class of neurotoxic insecticides, act as agonists of nicotinic acetylcholine receptors, “persist under field conditions, and are water soluble, enabling them to translocate into plants and provide systemic protection of seedlings,” the researchers note. They continue, “[T]hese insecticides pose a risk to resident macrofauna, such as ground beetles (Coleoptera: Carabidae), which spend most of their lives in and around soil.” (See studies here and here.)