CO₂ narcosis influences the memory of honey bees

Carbon dioxide is a relatively inert gas produced as a by-product of cellular respiration and is often used during various experimental manipulations of bees, as well as in beekeeping practices. However, a high concentration of carbon dioxide can affect the fitness of insects and even shorten their lives. Here, we tested the impact of exposure to carbon dioxide on the memory of foraging bees by performing a field experiment to test the spatial orientation of bees in terms of their ability to return to the nest. Additionally, we performed two laboratory experiments designed to test the short- and long-term memory of workers. Carbon dioxide had a clear negative impact on both the short-term memory and, uniquely, the long-term memory of worker bees. The laboratory results were confirmed by the field study, in which the bees had difficulty finding their way back to the nest after treatment with carbon dioxide. These results indicate that the use of carbon dioxide on foraging workers in research experiments should be limited, as it can indirectly affect the results of scientific research as well as colony conditions.