Honey bee queens transfer pesticides to eggs to reduce personal chemical load

A new study has identified a biological mechanism in honey bee queens known as ‘maternal offloading,’ where queens transfer accumulated pesticides into their eggs to reduce their own chemical burden.

While worker bees typically act as a filter for the colony, their ability to remove contaminants decreases with repeated exposure. When worker protection reaches its limit, queens move the chemical load into their eggs. This process protects the queen's immediate health but poses significant risks to the next generation, as contaminated eggs may result in poor development or unhealthy larvae.

Researchers used methyl parathion as a model compound to demonstrate that this mechanism can contribute to gradual colony decline.

Separately, research from the University of Kentucky and Tufts University investigated whether phytochemicals in honey influence forager aggression or the gut microbiome during honey robbing behaviors. The study found no evidence that these phytochemicals trigger increased aggression or alter the microbiome composition in honey bees.