The effect of pesticides on bumblebees is highly dependent on temperature. In this respect informs Imperial College London.
Some pesticides, especially some neonicotinoids, are known to affect bumblebees and other important insects, reducing their populations. At the same time, explanations for this effect vary around the world and do not fit into one system.
Now British scientists have discovered that the nature and strength of the effect can change significantly under the influence of temperature. To do this, they monitored six parameters of the behavior of these insects under the influence of two pesticides (neonicotinoid imidacloprid and sulfoximine sulfoxaflor) at three temperatures (21, 27 and 30 degrees). Imidacloprid had a stronger effect on four behavioral parameters at low temperatures: reaction rate, propensity to move, walking speed, and food intake rate. This suggests that pesticides can significantly interfere with nest maintenance tasks during colds.
However, the effect of imidacloprid on flight range, the most important indicator of behavior, was most pronounced at high temperatures. At the same time, the flight distance was the same in the range of 21 to 27 degrees, and then fell sharply when it reached 30 degrees. It is the maximum flight range of bumblebees and other pollinators that plays a decisive role in the successful cultivation of crops and the preservation of wild plant populations.
According to the authors, the resulting effect should be taken into account by farmers and other workers of the agro-industrial complex when processing the territory with pesticides. Also, the study pointed to another vulnerability of bumblebees to global warming.