Dr. Jamie Ellis, in a lecture at The National Honey Show in England late last year, stated that "our queens" (in the US) typically last eight to ten months. I noted a couple queen losses over winter as well (my grafted queens). And in the past three years, have noted supersedures after two to four weeks on purchased queens.
I guess a queen lives in exposure to whatever the foragers bring in, and that can affect her negatively in a hurry. Was just reading about pesticide exposure today. Workers, when they are not killed outright, bring home low doses of fungicides and pesticides. Also doing some reading on Nosema Ceranae, it can surprise you too.
Thanks again Jack, for introducing me to That other web site via your youtube robovac video.....and I followed you here too. :-)