Insect Repellent Chemical Severely Impairs Bumblebees' Navigation to Nests
A new study reveals that prallethrin, a pyrethroid-based insecticide used in common insect repellents like Thermacell devices, significantly impairs bumblebees' ability to find their way back to their nests. Researchers at the University of Turku, Finland, found that even brief exposure drastically reduces return rates, threatening colony survival by hindering food collection. The findings highlight an urgent need to reassess the ecological safety of household insecticides.
New research from the University of Turku in Finland indicates that a chemical commonly found in insect repellents, prallethrin, severely compromises bumblebees' navigation skills. Prallethrin, a synthetic pyrethroid-based insecticide used in devices like Thermacell for mosquito control, has been under scrutiny for its environmental impact, with this study providing crucial data. Published in the journal Biology Letters, the study involved exposing 167 buff-tailed bumblebees to prallethrin for varying durations (1, 10, or 20 minutes) before releasing them a kilometer from their nests and monitoring their return over three days.The results were stark: while 37% of the unexposed control group returned, only 17% of bees exposed for 10 minutes found their way back, and a mere 5% returned after a 20-minute exposure. Importantly, laboratory tests confirmed that the exposure did not increase bee mortality, suggesting the effect is specifically on navigation, not direct toxicity. Senior research fellow Olli Loukola emphasized that returning to the nest is vital for colony survival and food acquisition. Researcher Kimmo Kaakinen added that impaired navigation leads to reduced food collection, weakening the colony, decreasing new queens, and potentially causing the entire colony's death. The study calls for a detailed reassessment of the ecological safety of household insecticides.
