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The drastic decline in honey bee numbers has become a serious problem in recent decades worldwide. Bee pollination is invaluable both from an agricultural point of view and in terms of its ecological importance. Beyond the practical and financial factors, society has a moral responsibility to protect biodiversity, minimise the negative impact of human activity and ensure the survival of species. Nowadays, the decline in the number of bee colonies is increasing due to the so-called colony collapse disorder, which can be caused by a combination of various factors. Parasites, pathogens, other stress factors and the use of pesticides can all play a role in the development of the phenomenon. The neonicotinoid insecticides are key compounds in today's intensive agriculture, of which acetamiprid has been shown to be a widely and safely used agent, however, further research is necessary to study its sub-lethal effects, especially in domestic bees.

The aim of our experiments was to investigate the effects of acetamiprid on the redox homeostasis of the bee central nervous system, which may consequently affect the animal's feeding habits, behaviour, reproduction, and may also contribute to the development of certain diseases and colony collapse disorder.

The adverse effects of acetamiprid are based on the induction of oxidative stress in addition to hyperpolarisation to nicotinic acetylcholine receptors, therefore in our experiments we investigated the extent of oxidative stress by determining the levels of hydrogen peroxide (H2O2), malondialdehyde (MDA) activity, reduced glutathione (GSH) and oxidized glutathione (GSSG) concentrations. We also investigated the protective effect of curcumin as an antioxidant compound alone and in combination with acetamiprid treatment.

Our results showed that H2O2 levels were significantly increased by acetamiprid and significantly decreased by curcumin as a protective treatment. We also observed a decrease in MDA levels following curcumin treatment, and both acetamiprid and curcumin significantly affected the function of the glutathione system.

Overall, we can conclude that acetamiprid clearly impaired the central nervous system antioxidant defence mechanism in honey bees, which adverse effects were largely attenuated by curcumin, making it a promising candidate for mitigating the effects of neonicotinoid exposure in the future, with results that may be of particular importance from both bee health and ecological perspective.