The experiment was set up in a way to mimic real-life foraging activity, offering the bees a variation of concentrations of thiamethoxam and multiple exposures to the pesticide. By using whole colonies, the researchers allowed the bees to preserve their usual social cues.
The team discovered that the so-called “naïve” bees appeared to prefer the “pure” solution (i.e. the one with no pesticide whatsoever). However, once an individual bee acquired a taste for the thiamethoxam, it kept going back for the pesticide-laced food. Apparently, it wanted another fix. Over time, they visited the pesticide-free solution less and the pesticide-laced food more – the 2 ppb appeared to be the favorite, seeing the biggest increase in feeding and the most feeding overall.
What’s more, this behavior continued even after they tried to “trick” the bees by switching up the feeders, suggesting bees are able to detect the pesticide and then actively seek it out.