The impact of exposure to multiple pesticide residues in beeswax on adult honey bee longevity in vitro

In western honey bee (Apis mellifera) hives, beeswax may limit bee exposure to harmful chemicals by serving as a sequestration matrix. However, trapped chemicals also may be slowly released into the hive environment, posing risks to bees through long-term exposure. Researchers have previously shown that beekeeper-applied active ingredients, such as fluvalinate and coumaphos, and some agricultural pesticides, like bifenthrin and chlorpyrifos, are highly prevalent in beeswax. Despite the accumulation of chemicals in beeswax, fewno studies have been conducted to evaluate the effects of this exposure on the longevity of individual adult honey bees. Here, we aimed to assess the toxicity in vitro of six pesticides frequently detected in beeswaxpesticides (amitraz, acrinathrin, chlorfenvinphos, coumaphos, chlorpyrifos and bifenthrin) and determine if the concentrations found in hives pose a risk to honey bees. We identified LC50 values (mg/g of wax) for each compound as follows: amitraz (1.310 ), chlorfenvinphos (0.731), chlorpyrifos (0.012), acrinathrin (0.504), coumaphos (0.104), and bifenthrin (0.237). The risk (calculated as the concentration in wax divided by LC50) ranged from 10⁻⁵ for bifenthrin to 5 × 10⁻4 for acrinathrin, suggesting that this route of exposure poses low risk to bee survival. This research is critical for elucidating furthering our understanding of the impact of pesticides on honey bees.