PRELIMINARY INSIGHTS ON THE BEHAVIOURAL AND BIOLOGICAL RESPONSE OF WORKERS AND DRONE OF APIS MELLIFERA TO PFAS EXPOSURE

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants, often referred to as “forever chemicals” given their chemical stability. Due to their widespread industrial use and improper disposal, now PFAS are ubiquitously detected with concerning concentrations in air, soil, water, and even in plant matrices such as pollen and nectar. Honey bees are well-established bioindicators and have long been used to monitor environmental quality. However, bee populations are increasingly threatened by multiple stressors, including chemical contaminants. To date, studies investigating PFAS effects on bees are limited, and no data are currently available for drones. In this preliminary study, we evaluated the behavioural responses and mortality of worker bees and drones following PFAS exposure (PFOA, PFOS and PFBA). Acute oral toxicity tests were conducted at the IZSVe insectary in August 2025. Groups of ten specimens were maintained in PFASfree cages and exposed to sugar syrup contaminated with the different PFAS. The dose levels was selected among those evaluated in acute oral toxicity tests were conducted at the IZSVe insectary in August 2025 (Zulian et al., in preparation). Both a positive control and a negative control were included. Histopathological analysis was performed on surviving individuals (results presented in other contribution). PFAS exposure resulted in increased and earlier mortality, particularly in drones. Neurological symptoms, including temporary immobilization, were observed, although partial recovery suggested possible detoxification mechanisms. Effects varied depending on both PFAS compound and bee caste, with drones appearing more susceptible, potentially due to their lower baseline exposure to environmental contaminants. These findings highlight the need for further investigation into their accumulation and biomagnification in acute, subacute, and chronic effects of PFAS on pollinators, including potential impacts on male fertility. Given the persistence of PFAS in the environment, strengthening regulatory measures and improving management strategies are essential to mitigate long-term ecological risks.