http://www.abc.net.au/rn/scienceshow/stories/2007/2093353.htm#transcript
Contains link to the audio and also a transcript of the discussion. Seems Pesticides and breeding in the US have a lot to answer for.
Also http://www.abc.net.au/rn/scienceshow/stories/2007/2098171.htm#transcript is about how Queen Pheremones affect Workers brains!