Alison McAfee 2019-09-09 10:54:38
Adoption of 5G cell phone networks will lead to more cell towers, but there’s no good reason to expect it to harm honey bees
The next generation of cell phone connectivity — the 5G network — has been launched. Most countries are projected to adopt the technology by 2020, and we should expect download speeds ten to twenty times faster than 4G as well as higher network capacity (i.e., more devices can be used on a network simultaneously), feeding our existing data addictions. For some people, the 5G launch has also renewed old concerns that cell phone-generated electromagnetic waves could be interfering with honey bee navigation.
It all started in 2006, when Dr. Jochen Kuhn, a professor at Landau University, Germany, and his colleagues released the seminal study (which, to the best of my knowledge, was never peer reviewed).1 The researchers placed DECT docking stations — digital enhanced cordless telecommunications stations, the kind used for cordless landline telephones — inside two mini-hives and powered them up. The two other hives did not get docking stations. They then trapped 25 bees at the entrance of each hive, released them 800 meters away, and recorded how many made their way home. They also measured comb areas in the hives, after giving the mini-colonies a chance to build up. The bees from docking-stationhives, as the old story goes, built less comb and were worse at finding their way home.
Data from two hives is obviously not enough to make any solid conclusions, no matter how well an experiment is designed. And well-designed, this wasn’t. The authors recognized this, writing that “because of the explorative character of [the] study we refrain from a differentiated statistical analysis.” In other words, the data were too sparse to apply standard statistical tests that all credible scientists use. And it didn’t even involve cell phones.
Even in the absence of stats, there were numerous design flaws. The researchers didn’t know if the bees they trapped had completed orientation flights or if they were going outside for the first time. Nor did they test wayfinding ability before and after powering up the DECT stations, to get baseline wayfinding aptitudes for each hive. Nor did they use controls with DECT stations that simply weren’t powered up (of course finicky bees in mini-hives will build less comb if there’s a giant object sticking up from the bottom of their hive). Sometimes, the authors describe using eight hives, but data from only four are reported. The flaws are infuriating, especially considering the hype this “research” garnered in the media.
In their defense, Kuhn and his colleagues were actually interested in using honey bees as a model to study effects of electromagnetic waves on humans, not honey bees (though this rationale is questionable, too). They never claimed to have found the cause of colony collapse disorder (CCD), a mysterious phenomenon which was hitting beekeepers hard at the time. As Kuhn told the New York Times,2 “We cannot explain the CCD-phenomenon itself and want to keep from speculation in this case. Our studies cannot indicate that electromagnetic radiation is a cause of CCD.” But in most cases, nobody listened.
I can understand why the story was so compelling. Honey bee biology is so alien, the idea that electromagnetic waves could cause honey bees to get lost doesn’t seem that far fetched. After all, honey bees do have ferromagnetic crystals, or magnetite, in their abdomens, which act as magnetic field sensors.3,4 There is some evidence that workers use this information to help navigate Earth’s geomagnetic fields, kind of like migrating birds and fish, although the relative importance of these cues for wayfinding is probably lower than their sense of smell and orientation with the sun. And there is not a shred of scientific evidence to suggest that honey bees build comb in specific orientations relative to geomagnetic fields and “ley lines,” either, as some people have suggested on popular fora. But to add to the scifi, honey bees also have other magnetoreceptors called cryptochromes in their brains5 (although there is not yet any indication that they are actually useful). When it comes to honey bee biology, the line between fact and fiction can be so blurry that it’s hard to know when it’s been crossed.
But the magnetoreception superpowers honey bees do have sense static magnetic fields, not electromagnetic waves. Magnetic fields are force fields, just like the pull you feel between a magnet and a metallic object. The same kind of force field orients the needle of a compass along Earth’s geomagnetic lines. Electromagnetic waves, though, are a different phenomenon: They are propagating oscillations of electric and magnetic fields. Unlike static magnetic fields, the waves travel through space at the speed of light and exhibit a massive range of wavelengths. Some of these wavelengths we can detect, and some of them we can’t.
For example, electromagnetic waves with wavelengths of 390 to 750 nanometers make up the familiar visible light spectrum; we perceive these particular electromagnetic waves (quite literally) as the colours of the rainbow with photoreceptors in our eyes. Honey bees have slightly different photoreceptors, allowing them to see ultraviolet light as well, which has wavelengths as short as 300 nm (while sacrificing perception of the longer, red-end wavelengths). We don’t have biological receptors for the electromagnetic waves that transmit digitized music to our car stereos, though: For those kinds of waves, we need electronic receivers.
Clearly, the force that spins a compass needle is a very different (though related) enigma from the light we see with our eyes. And just as the electromagnetic waves forming the colour blue are different from radio waves, those transmitted between cell towers are different from DECT stations. Other structures, like power lines, do produce magnetic fields which honey bees could theoretically sense. But they are short-range, and honey bees have no business flying near power lines anyway. As many writers have pointed out before me, the notorious German “cell phone” study was massively overblown, experimental flaws aside.
There is still no solid evidence that electromagnetic waves, like those sent and received by cell phones, are bad for honey bee health. Some follow-up studies, like one published by Ritu Taye in 2018,6 attempt to resurrect the cell phone hypothesis by recording Asian honey bee foraging activity when colonies were placed between 100 m and 1,000 m from a cell phone tower. They found that bees from colonies placed 100 m away brought in the least pollen, and bees from colonies 500 m away brought in the most. Congratulations! Most likely, the ominous structure, landscaping, or shadows around the cell tower disrupted their foraging efficiency. Alternatively, the small differences in foraging propensity could have been influenced by equally small differences in time of day during the recordings or strength of the few colonies placed at each distance, neither of which were recorded. These are the reasons why researchers repeat the classic warning, “correlation does not equal causation.”
But correlations are still informative. If I were researching this topic, the first thing I would do is map the locations of reported colony losses in relation to existing cell towers, and look for a relationship between tower proximity and colony death. Yes, colony death is an extreme outcome, but if the cell towers’ electromagnetic waves are sufficiently bad for honey bee health for us to worry about, then there should be a correlation with colony mortality. It may be a weak correlation, but it should be there. And in cases where new towers are built where colonies already exist, a convenient natural experiment emerges. To the best of my knowledge, no one has done this exercise.
It has been over ten years since Kuhn’s cell phone study made its rounds in the media, but the topic has been resurfacing. More recently, a European Union “support mechanism” project called EKLIPSE synthesized a report on the impacts of electromagnetic waves on wildlife, as requested by the non-profit, Buglife. They assembled a group of stakeholders and scientists to review the existing literature, and published an opinion report in 2018.7 Their main conclusions, as far as invertebrates were concerned, were that more research is needed, and that research needs better, standardized protocols. But of course, the headline run by The Telegraph8 was “Electromagnetic radiation from power lines and phone masts poses ‘credible’ threat to wildlife, report finds.”
As 5G technology becomes more mainstream, we should expect a resurgence of the cell phone hypothesis. The 5G network will utilize electromagnetic waves oscillating at different frequencies than 4G networks. The waves will have longer wavelengths and will probably require higher densities of cell towers because the waves themselves can’t easily travel through solid structures. I am not dismissing electromagnetic waves, from 5G cell phones or otherwise, as a topic of research: I recognize that sometimes you don’t know what you don’t know. But as of yet, there is no solid evidence that existing cell phone networks harm honey bees, so I’m not worried about 5G networks either.
REFERENCES:
1.Harst W, Kuhn J, and Stever H. (2007). Can electromagnetic exposure cause a change in behaviour? Studying possible non-thermal influences on honey bees – An Approach within the Framework of Educational Informatics.
2.Sylvers E. (2007). Case of the disappearing bees creates a buzz. The New York Times.
3.Liang C et al. (2016). Magnetic sensing through the abdomen of the honey bee. Scientific Reports. 6:23657.
4.Lambinet V et al. (2017). Linking magnetite in the abdomen of honey bees to a magnetoreceptive function. Proceedings of the Royal Society B. 284: 20162873.
5.Velarde RA et al. (2005). Pteropsin: A vertebrate- like non-visual opsin expressed in the honey bee brain. Insect biochemistry and molecular biology. 35: 1367-77.
6.Taye R et al. (2018). Effect of electromagnetic radiation of cell phone tower on development of Asiatic honey bee, Apis cerana F. (Hymenoptera: Apidae). International Journal of Current Microbiology and Applied Sciences. 7(8): 4334-39.
7.Malkemper EP et al. (2018). The impacts of artificial Electromagnetic Radiation on wildlife (flora and fauna). Current knowledge overview: a background document to the web conference. A report of the EKLIPSE project.
8.Knapton S. (2018). Electromagnetic radiation from power lines and phone masts poses ‘credible’ threat to wildlife, report finds. The Telegraph.
Alison McAfee has a PhD in genome science and technology from the University of British Columbia, where she studied mechanisms of hygienic behaviour in honey bees. She is now a post-doc at North Carolina State University in David Tarpy’s lab, and studies what keeps honey bee sperm alive.
Email her at alison.n.mcafee@gmail.com.
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