Electromagnetic fields emitted by transmission towers — such as those supporting overhead power lines that carry electricity from power plants to cities — disrupt the pollination abilities of bees. This disturbance could also have a significant impact on the biodiversity of these environments.
Honey bees often depend on natural electromagnetic fields (EMF) to navigate their environment – they have a specialized magnetoreception system in their abdomen. A growing body of research has already suggested that exposure to man-made EMFs can be disorienting to bees, sometimes causing them to get lost on their way home after foraging, and even leaving entire colonies without enough foragers to survive in some areas. case.
Gabriel Ballesteros at the University of Talca in Chile, and his colleagues exposed 100 bees (Apis mellifera) at different levels of high voltage and low frequency EMF in a laboratory for 3 minutes at a time. Compared to bees exposed to low levels, those subjected to more intense EMFs produced around 50% more heat shock proteins – normally caused by high heat, these molecules protect cells from stress. The researchers also found a significant decrease in the expression levels of genes associated with the bees’ abilities to forage, form memories and navigate.
The researchers also observed bees in the wild in Quinamávida, Chile, and compared populations in areas with active or inactive high-voltage pylons. They found that for bees selected near active transmission towers, the number of heat shock proteins doubled after just 5 minutes. Bees near active high voltage towers also visited the surrounding California poppy plants (Eschscholzia californica) only a third as often as those who are not exposed to electromagnetic fields.
“The bees avoided the flowers that were near the overhead lines,” says Ballesteros. “They kind of flew to the flowers, but then they just prefer to stay away.” He says plant populations were also less varied and abundant in those same areas.
That may not be all, according to Henry Lai and his colleague B. Blake Levitt of the University of Washington in Seattle, who have studied the effects of EMFs on plants and animals. They say the study only looks at one type of EMF exposure in nature, but it’s rare today to find an environment with just one source of EMFs. For example, cell phone antennas emitting radio frequency radiation are sometimes mounted directly on high-voltage transmission towers, so bees are often exposed to multiple frequencies. Even emissions from the researcher’s cell phones, if in active call mode, could make a difference, and the researchers did not note whether cell towers were located nearby. Levitt and Lai also note that the study does not mention whether field sites near the towers have been tested for pesticides, which are commonly used to keep these areas clear of vegetation and could affect bees.