A new study that involved fitting bees with unique tracking tags shows that exposure to a common pesticide neonicotinoid dramatically affects bees’ health and impairs their social behavior.
Bees are important pollinators of plants and crops and their performance greatly depends on their social behavior and interactions. But exposure to pesticides seems to prevent bees from their day to day activities.
To gain a better understanding of pesticide exposure on bees, researchers created an innovative robotic platform and monitored bee activity using an advanced tracking system. Researchers found that bees exposed to neonicotinoid pesticide spent less time feeding and nursing larvae. It also hampers their ability to warm the nest and to build or repair wax caps around a colony.
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When social behavior is disrupted and the care of the young ones or next generation of bees is not properly done, the population of bees becomes more susceptible to decline.
“Foraging is only a part of what bumblebees do. Those studies were picking up on the important effects these compounds were having on what's going on outside the nest, but there's a whole world of really important behaviors going on inside...and that's a black box we wanted to open up a bit,” said lead study author James Crall.
“What we do is put a black and white tag with a simplified QR code, on the back of each bee. And there's a camera that can move over the colonies and track the behavior of each bee automatically using computer vision...so that allows us to look inside the nest."
Bees live in colonies which contain hundreds or even thousands of individuals, all working together and interacting as one “superorganism.” Using new tracking system, researchers were able to see into these complex structures and observe behavioral changes among bees before and after exposure to pesticides.
The robotic platform contained 12 colonies. In pesticide affected colonies, bees spent more time alone or on the edges of the nest. The impact was strongest at night.
“Bees actually have a very strong circadian rhythm," said Crall. "So what we found was that, during the day, there was no statistically-observable effect, but at night, we could see that they were crashing. We don't know yet whether (the pesticides) are disrupting circadian gene regulation or if this is just some, maybe physiological feedback...but it suggests that, just from a practical perspective, if we want to understand or study these compounds, looking at effects overnight matters a lot."
