Researchers have traced the movements of bumblebees by sticking QR codes behind them. They also created a system that tracks individual bees exposed to imidacloprid, a neurotoxin belonging to the group of neonicotinoid pesticides. Neonicotinoids are the most common class of insecticides globally.
Initial tests show that even if a neonicotinoid such as imidacloprid, a common insecticide, does not completely kill a bee, it can cause other changes to it. In fact, we can see important behavioral changes over time that affect the functions of the colonies and growth in the long run. Previous research shows, for example, that neonicotinoids can affect the ability of bees to navigate and find flowers, thus affecting the nutrition of colonies.
However, what is happening within a colony exposed to neonicotinoids has been more difficult to analyse. A team of researchers set up a dozen bumblebee colonies, each located in a transparent acrylic box. Some colonies were exposed to Imidacloprid and others were not; they were monitored by a system of robotic cameras for about 5 minutes, 12 times a day. Since each bee has a QR code on the back, a computer vision system can keep track of its movements day and night. The researchers found impressive differences between the two types of colonies, in particular the bees are less active, they rest longer. They also remain further away from the larvae that require care. In particular, the larvae must be warmed up by healthy bees through muscle vibration. Bees exposed to Imidacloprid cannot adequately heat the larvae, which may have implications for the development of the juveniles.
The behaviour of honeybees, whose colonies number thousands, is also influenced by the presence of neonicotinoids. The impact on nectar research performance, however, is less than that of a small colony of bumblebees or a solitary bee, because the failure of an individual to perform this function can be masked by other individuals who come out looking for nectar. Good news for honeybees! Bees are in trouble, yes. But with innovative techniques like this, scientists are getting a better understanding of what is putting them at risk.