by: James E. Tew
After several hundred years of observations, there are still plenty of mysteries behind the closed doors of the beehive. As beekeepers, we have always given simple answers to complicated bee questions. In most instances, our only other alternative was to give no answer at all.
During the Spring of 2002, numerous
My first association with this peculiar ailment was about 20 years ago, when I talked to the late Dr. Walter Rothenbuhler about the sickness. He had attempted to work on the problem, but never made much headway. Though he had performed several research projects, no conclusions were ever drawn. Scant research attention has been allocated to this syndrome over the years. Like an urban legend, the disease lives in scattered paragraphs in bee books near the end of the requisite chapter on bee diseases.
The condition was first described in 1915 and was called Disappearing Disease because the disease was self-limiting and disappeared. Through the years, that name has increasingly been broadened to describe any mysterious instance where adult bees disappear - not the disease. Confusing isn t it? If the bees have disappeared, then the disease is gone, too. Right? From 1915 until this time, no single pathogen has even been isolated. Other possible names for the ailment are: Spring Dwindling, Fall Dwindling, May Disease, and Autumn Collapse. The Isle of Wight Disease, caused by tracheal mites, has many similarities to Disappearing Disease. The reported symptoms are broad and indistinct appearing to be a collage of characteristics.
In 1915, after a particularly wet Spring, significant colony losses were reported. One beekeeper lost 400 hives. The problem was noted in multiple states from
Characteristics of Disappearing Disease
Adult bee loss with no accumulation at the hive entrance.
Adult bee loss after a cool damp Spring - though losses have also been reported in the Summer and Autumn.
Queens are the last hive individuals to be affected.
Pollen and honey stores are strangely normal.
A disproportionate brood/adult bee ratio.
Honestly, characteristics are broad and indistinct - except for one - adult bees are mysteriously gone. In 1985, Dr. Roger Morse wrote, 'It seems unlikely that any one cause produces all the losses attributed to Disappearing Disease1.'
Having already admitted that a single causative agent has never been isolated, guesses have been postulated that could justify the problem. I have presented them in no order of priority.
Possible Causes of Disappearing Disease
Environmental conditions (predominantly weather)
Toxic pollen or nectar
Is this disorder a mystery?
I don t know what to say. As beekeepers, we all know that bad things can happen to good hives. With tongue-in-cheek, I suggest that this syndrome should be called the Miscellaneous Disease for it appears that any pathogenic problem of unknown origin that causes adult bee loss can be dumped in this group. The symptoms and specifics are just too broad to neatly fit into one grouping. As currently described, Disappearing Disease is not diagnosable, being nothing more than a list of disassociated symptoms. This is not say that something is not wrong within the affected colony, but rather we simply don t know where to place the blame. It follows then, that no control recommendations can be made.
A diagnosis of Disappearing Disease begs sarcasm and dark humor. How can you study the problem if there are no bees to study? I have no specific photographs for you in this component of this article because there is nothing to photograph. Beekeepers with full honey supers on hives with no bees humorously have said that at least the colonies were gentle to rob. But to commercial beekeepers who are trying to make a living at bee keeping, this occasional condition is anything but amusing. Thankfully, it is not a common condition and appears to be self-limiting. But to beekeepers who have lost revenue and income, it is easy to be concerned - even superstitious. If you don t know what you did incorrectly, then you don t know what to do differently next season.
Sooner or Later
Sooner or later, apicultural science, in its lumbering fashion, will develop explanations and suggest solutions to various aspects of what is now occasionally called Disappearing Disease. Until that time, I suppose the diagnosis of Disappearing Disease serves a useful function in that, at least, we have a broad, indistinct category in which to place the occasional inexplicable and abrupt loss of adult bees. They just disappeared.
Dr. James E. Tew, State Specialist, Beekeeping, The Ohio State University, Wooster, OH 44691