Interesting question, and the answer may be cell phones.
[Scientists] are putting forward the theory that radiation given off by mobile phones and other hi-tech gadgets is a possible answer to one of the more bizarre mysteries ever to happen in the natural world – the abrupt disappearance of the bees that pollinate crops. Late last week, some bee-keepers claimed that the phenomenon – which started in the US, then spread to continental Europe – was beginning to hit Britain as well.
The theory is that radiation from mobile phones interferes with bees’ navigation systems, preventing the famously homeloving species from finding their way back to their hives. Improbable as it may seem, there is now evidence to back this up.
Interesting answer even though the article is half informative and half alarmist claptrap.