>Would you accept circumstantial evidence? Circumstantial evidence certainly suggests suspected factors that should be investigated. One thing that helps us here is that although Apis mellifera is the common "victim," the presence of the factors suspected as being "the cause" for elevated colony mortality vary greatly from continent to continent, from location to location (such as exposure to ag chemicals only in ag settings), and even by individual management (does one treat with particular synthetic miticides). This fact allows us to look for suspects that are common to all localities, or absent from some. What we'd especially be interested in are changes in the presence of the suspect around 2004, at which time we started to notice elevated colony loss rates. There was widespread failure of currently used miticides during that time period, and varroa frequently got out of hand. There appears also for there to be a trend in which the mite-vectored viruses also evolved into more virulent forms, although this timing varies from country to country. Nosema ceranae also circumstantially invaded most continents concurrent with elevated colony losses, and would be on my list of major suspects. A number of countries are also experiencing epidemics of new forms of EFB or EFB-like brood disease, also occurring in the same time frame (this was strongly associated with my major collapses in 2005/2006). Other concurrent changes are climate change, major changes in agricultural practices (a shift towards more maize and fewer hedgerows), virus evolution due to the presence of the vector varroa, and changes in miticide use. Coumaphos contamination is a common factor in many countries, as is the use of amitraz (which in the U.S. generally correlates with the advent of increased winter mortality). In the U.S., tylosin was approved for use in the fall of 2005. But since it is not used in some other countries, we can likely eliminate it as the cause. As far as the neonics, the timing of neonic use is common in ag localities in most countries, but varroa is not present in Australia. So we can check to see whether colonies exposed to neonics in Australia crash as is claimed for those in France. And then there are the introductions of other pesticides at about the same time as the neonics, which most everyone is ignoring. For example, go to the USGS maps of pesticide application over the years:http://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php. Click on pyraclostrobin (a fungicide). Then click on the maps from 2000 to 2009. You may note that its use in the U.S. also closely coincides with elevated colony mortality, which began about 2004. I'm not saying that pyraclostrobin causes elevated colony loss, but just that if one is going to look for circumstantial evidence, one should investigate ALL suspects, not just your favorite. -- Randy Oliver Grass Valley, CA www.ScientificBeekeeping.com *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html