Pity the poor honeybee. Since 2003, bee colonies around the globe have declining at an alarming rate. And since bees play a vital role in agricultural production, that's bad news for us humans. Scientists suspect many factors may be responsible, including pesticides, viruses, the varroa mite, genetically modified crops, and even exceptionally cold winters. Now we can add cellphones to the list of possible culprits.

A study by Swiss researcher Daniel Favre shows that mobile phone-generated electromagnetic fields may contribute to Colony Collapse Disorder (CCD), a condition that causes worker bees to desert the hive. In most cases, the queen bee is left with eggs, immature bees, and a lot of honey. The colony survives for a short time, but soon dies out without its workers.

"Recent efforts have been made to study another potential cause responsible for bee losses: manmade electromagnetic fields," Favre writes. And while the results obtained to date have been "highly controversial," they suggest a connection between the growing use of cellphones and a declining bee population.

Earlier studies have shown that cordless telephones placed at the bottom of beehives altered the behavior of honeybees that returned to the hive after foraging. However, other reports have failed to find a connection between mobile phones and colony collapse.

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Favre's 2009 study exposed honeybees to active cellphone radiation. "The goal of these experiments was to identify potential effects of mobile phone communications on honeybee behavior," he writes.

The researcher recorded sounds produced by bees in five healthy hives in two Switzerland locations between February and June 2009. The study recorded the bees' sounds with active mobile phones in the hive. Two mobile handsets (900MHz GSM) were chosen at random.

The bees were also 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. A connection was made after 5 to 10 seconds of ringing.

Sound analyst shows the bees weren't disturbed by inactive or standby mobile phones. However, active cellphones confused the bees, creating "worker piping," or a signal to leave the hive.

The findings suggest that "the behavior of the bees remained perturbed for up to 12 hours after the end of the prolonged mobile phone communication," Favre writes. "This observation means that honeybees are sensitive to pulsed electromagnetic fields generated by the mobile telephones."

More Study Needed

In real life, of course, you won't find mobile phones in beehives. And further studies are needed--those that place cellphones at greater distances from the bees--to study the connection between odd honeybee behavior and mobile phone-generated electromagnetic fields.

Favre points to a recent experiment suggesting that cellphones and cellphone towers located near beehives hamper honeybee navigation.

"In one experiment, it was found that when a mobile phone was kept near a beehive it resulted in a collapse of the colony in 5 to 10 days, with the worker bees failing to return home, leaving the hives with just queens, eggs, and hive-bound immature bees," he writes.

Contact Jeff Bertolucci via Twitter (@jbertolucci) or at jbertolucci.blogspot.com.