There are many current theories on why there have been such significant declines in honeybee numbers in recent years. Essentially most of these include losses due to the varroa mite, pesticide poisonings, potential immune-suppressing stress on bees (caused by one or a combination of several factors such as apiary overcrowding, pollination of crops with low nutritional value, pollen or nectar death), drought, monoculture practices and increased transmission of pathogens. However, a study by Farve, D (2011) aimed to investigate another potential and unexplored cause responsible for bee losses: manmade electromagnetic fields.
In this study, electromagnetic waves that originate from mobile phones were tested to determine whether there were any potential effects on honey bee behaviour. As strange as it seems mobile handsets were placed within close proximity to the honey bees and the sound made by the bees was then recorded and analysed using audiograms and spectrograms. These revelled that mobile phone handsets did indeed have a dramatic impact on bee behaviour, in particular by inducing the piping signal of the worker bees.
So what is a piper signal you might ask and why might bees be influenced by electromagnetic waves? Well it has been known for decades now that worker piping is associated with disturbance of the hive for example by intruders or by jarring and therefore might explain why phone hand set triggered disturbances in the hive in similar way. Honeybees also possess magnetic crystals in their fat body cells and it has been shown that honeybees can be trained to respond to very small changes in the constant local geomagnetic field intensity. This could potentially have implications for the foraging behaviours of the bees.
The bees were recorded during their normal activities, both with and without inactive mobile phones. With the active devices, the first handset was triggered to call the second phone in the hive. It was found that although the mobile phones did not change the bee activities it did confuse the bees, creating "worker piping," or a signal to leave the hive. The findings suggested that the behavior of the bees remained perturbed for up to 12 hours after the end of the prolonged mobile phone communication. Thus, suggesting that honeybees are somewhat sensitive to pulsed electromagnetic fields generated by the mobile telephones.
Results concluded that the induction of honeybee worker piping by the electromagnetic fields of mobile phones might have dramatic consequences in terms of colony loss due to unexpected swarming. Furthermore, other studies have also found that electromagnetic fields can interfere with honey bee navigation when hives were located near cell phone towers or in close proximity to a cell phone. Where when a cell phone was kept near a beehive it was found to result in the collapse of the colony in five to ten days. This occurred because worker bees failed to return home, leaving the hives with just the queens, eggs and hive-bound immature bees.
More research is clearly needed to attribute electromagnetic fields as an explanation for the “disappearance” of bee colonies around the world. The colony collapse phenomenon currently accounts for 43% of all bee losses as recently described in a national survey performed in the United States. However, with the world’s population continuing to grow and the increasing demand for technological products, this could potentially be of relevant consideration as a means to prevent further honey bee decline in the future.
Farve, D. (2011). Mobile-phone induced honeybee worker piping. Apidologie.DOI: 10.1007/s13592-011-0016-x
