TDK conference 2024

The global decline in western honey bee populations over recent decades poses a significant threat to agricultural productivity and ecosystem health. In the past 15 years, a phenomenon known as Colony Collapse Disorder (CCD), has been observed worldwide. The hallmark of CCD is a significant loss of worker bees, while the colony itself shows no clear signs of disease. Initially, this issue was attributed solely to factors such as parasites like Nosema and Varroa, or the presence of other infectious diseases. However, it has since become evident that CCD is a complex process involving multiple factors, including climate change, pollution, infections, and pesticides.

The growing demand for food and feed due to the expanding global population has made the widespread use of pesticides essential. Among the most commonly used pesticides are neonicotinoids, with acetamiprid being a newer generation compound that has a more favorable toxicity profile. However, previous studies have shown that acetamiprid can induce oxidative stress in various species, including bees, even at sub-lethal levels of exposure. Despite this, there is limited information on its impact on fatty acid metabolism. Given that phospholipids are essential for maintaining cell membrane structure, disruptions in oxidative balance in the central nervous system, along with alterations in fatty acid metabolism, could potentially compromise cell viability.

We investigated the effects of acetamiprid on the fatty acid profile of honey bees. Bees were treated with acetamiprid mixed into sugar syrup for a period of 48 hours. After dissecting the brainstem on ice under a stereomicroscope, the samples were homogenized, and the concentrations of the 15 most abundant fatty acids were analyzed using gas chromatography-mass spectrometry (GC-MS).

We observed significant increases in lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), and alpha-linolenic acid (C18:3, n-3). Total fatty acid concentrations, as well as polyunsaturated fatty acids (PUFA) and saturated fatty acids (SFA), also showed increases. In addition, significant changes in the ratios of these fatty acids were noted.

These findings suggest that acetamiprid not only affects redox homeostasis, as previously reported by our research group, but also impacts lipid metabolism in the central nervous system. Our results provide important insights into the detrimental effects of neonicotinoids on bees, which has both fundamental scientific importance and practical implications for agricultural strategies aimed at developing new protective measures.